THE EFFECTS OF ATTENTIONAL FOCUS INSTRUCTIONS ON SIMULATED UPPER EXTREMITY AMPUTEES? MOVEMENT KINEMATICS WHEN LEARNING A NOVEL FUNCTIONAL TASK Except where reference is made to the work of others, the work described in this dissertation is my own or was done in collaboration with my advisory committee. This dissertation does not include proprietary or classified information. _________________________________ Robert Barron McAlister Certificate of Approval: Mary E. Rudisill Mark G. Fischman, Chair Professor Professor Health and Human Performance Health and Human Performance J. Troy Blackburn Wendi Weimar Assistant Professor Associate Professor Exercise and Sport Science Health and Human Performance University of North Carolina, Chapel Hill Anthony Guarino Joe F. Pittman Associate Professor Interim Dean Educational Foundations, Leadership Graduate School and Technology THE EFFECTS OF ATTENTIONAL FOCUS INSTRUCTIONS ON SIMULATED UPPER EXTREMITY AMPUTEES? MOVEMENT KINEMATICS WHEN LEARNING A NOVEL FUNCTIONAL TASK Robert Barron McAlister A Dissertation Submitted to the Graduate Faculty of Auburn University in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy Auburn, Alabama December 15, 2006 iii THE EFFECTS OF ATTENTIONAL FOCUS INSTRUCTIONS ON SIMULATED UPPER EXTREMITY AMPUTEES? MOVEMENT KINEMATICS WHEN LEARNING A NOVEL FUNCTIONAL TASK Robert Barron McAlister Permission is granted to Auburn University to make copies of this dissertation at its discretion, upon requests of individuals or institutions and at their expense. The author reserves all publication rights. Signature of Author Date of Graduation iv VITA Robert Barron McAlister, son of C.E. McAlister and Virginia B. McAlister, was born on February 26, 1964 in Winterpark, Florida. He grew up in three cities: Jacksonville, Florida; Jackson, Tennessee; and Columbus, Georgia. He graduated from Shaw High School in Columbus, Georgia, in 1982. The same year, he enrolled in Rhodes College in Memphis, Tennessee. After transferring, Robert graduated in 1986 with a Bachelor of Arts in English from the University of Georgia. After working in a variety of jobs, he entered the Occupational Therapy program at the Medical College of Georgia (MCG) in 1993. Graduating in 1995, he then obtained certification in Neuromuscular Massage from the Academy of Somatic Healing Arts in Atlanta, Georgia, in 1997. In 1999, he received an Occupational Therapy faculty appointment from MCG, and began teaching at the Columbus State University distance education campus. In 2000, he entered the Masters of Health Education program at MCG and graduated in 2002. In 2002, Robert was promoted from the level of instructor to assistant professor. In the fall of 2002, he entered Auburn University?s doctoral program in Motor Behavior. While in the doctoral program, he has continued to teach full time at MCG. He has also taught professional level continuing education courses in Myofascial Release and Physical Agent Modalities. He is married to Melanie McAlister, and has one daughter, Zoe Elizabeth McAlister. v DISSERTATION ABSTRACT THE EFFECTS OF ATTENTIONAL FOCUS INSTRUCTIONS ON SIMULATED UPPER EXTREMITY AMPUTEES? MOVEMENT KINEMATICS WHEN LEARNING A NOVEL FUNCTIONAL TASK Robert Barron McAlister Doctor of Philosophy, December 15, 2006 (M.H.E., Medical College of Georgia, 2002) (B.S., Medical College of Georgia, 1995) (B.A., University of Georgia, 1986) 182 Typed Pages Directed by Dr. Mark Fischman An important question in motor learning concerns where attention should be focused when learning a new task. The majority of the literature dealing with this subject suggests that an external (visual, or task-related) focus of attention produces better results than an internal (proprioceptive, or movement-related) focus of attention. While many studies have explored the effect of attentional focus instructions on motor learning in healthy participants, none have dealt with upper extremity amputees. Furthermore, although occupational and physical therapists teach motor skills on a daily basis, there has been little research exploring the best way to teach these skills to patients. This study examined the effects of attentional focus instructions on 30 healthy, college-aged males and females who used a simulated transradial upper extremity vi prosthesis to learn a novel functional movement task. The experimental task required participants to use the prosthesis to pick up a cup of cereal, pour the cereal into a bowl, move the bowl full of cereal to a plate, and then pick up and transport the bowl of cereal on the plate to a new location. The experiment took place over three sessions and allowed ten trials per session. Sessions one and two were skill acquisition sessions, and session three was a retention session. Participants were randomly assigned to one of three groups: external focus, internal focus, or control. On session one, all groups were shown a video that briefly explained how to use the simulated transradial prosthesis. External and internal focus groups were shown an additional video that instructed them to attend either externally or internally. On session two, internal and external focus groups again viewed the attentional focus video. No videos were shown on session three. The following variables were measured: movement time, movement units, plate pitch and plate roll, and amount of cereal spilled. No significant differences (p > .05) were found between groups during acquisition or retention for the following variables: movement time, movement units, plate pitch and plate roll. However, there was a statistically significant difference between groups for the amount of cereal spilled. While moving as quickly as the other groups, the external focus group spilled significantly less cereal during both skill acquisition and skill retention sessions. Furthermore, in the absence of attentional focus instructions, nine out of 10 control group participants reported using an external focus approach in post-experiment interviews. These findings suggest that occupational and physical therapists may help their patients learn how to use an upper extremity prosthesis more effectively by using instructions that encourage an external focus of attention. vii ACKNOWLEDGMENTS Many individuals contributed to the completion of this work. I owe my deepest appreciation and thanks to Dr. Mark Fischman, who patiently guided and supported me throughout this process. Dr. Troy Blackburn provided technical expertise and insights that were critical to completion of this study. Dr. Rudisill and Dr. Weimar continually expected the best of me, offering helpful critiques and comments, and this support was invaluable. I am grateful for the statistical assistance Dr. Guarino offered. Sincere thanks are also extended to Chad Duncan, who fabricated and maintained the prosthesis. The support of my students throughout this process has also been appreciated. Graduate student assistants Stephanie Bass, Heather Carroll, Amy Mims, Felix Okam, Meaghan Reilly, Elisa Sammons, and Michelle Whitaker all provided much needed assistance carrying out the experiment. In addition, the support of Medical College of Georgia faculty and staff was welcomed and appreciated. Dr. Kathy Bradley, Dr. Ricky Joseph, and Mrs. Sharon Swift offered exceptional understanding and advice, while Dorie Biskup cheerfully provided much needed help typing and formatting the tables. Finally, I would like to thank my family. My wife, Melanie, offered constant love and encouragement, and was a great advisor and friend whenever I needed her. My daughter, Zoe, helped me to keep everything in perspective. Her active mind, playful heart, and beautiful spirit kept me in contact with the truly important elements of life. viii Style manual or journal used: Publication Manual of the American Psychological Association, 5 th Editon. Computer software used: Windows XP, SPSS 1311.5 for Windows, and National Instruments Labview 7.1 ix TABLE OF CONTENTS LIST OF TABLES..................................................................................................... xii LIST OF FIGURES ................................................................................................... xiv I. INTRODUCTION ......................................................................................... 1 Statement of the Purpose ............................................................................... 6 Hypotheses..................................................................................................... 7 Delimitations.................................................................................................. 8 Assumptions................................................................................................... 8 Limitations of the Study................................................................................. 9 Definition of Terms........................................................................................ 10 II. REVIEWOF LITERATURE ......................................................................... 12 Attentional Focus........................................................................................... 12 Competing Evidence: Skill Level and Attentional Focus.................. 18 Attentional Focus Theories................................................................ 21 Attentional Focus and Occupational Therapy................................................ 22 Instruction and Feedback ................................................................... 26 Upper Extremity Amputee Studies ................................................................ 31 Prosthetic Training Techniques ......................................................... 33 Amputee Training and Motor Learning Practice Designs ................. 37 Brain Plasticity, Movement Complexity, and Motor Planning...................... 40 Event-Related Studies and Motor Pathways...................................... 42 Movement Complexity and Motor Pathways .................................... 43 Visuo-Motor Planning ....................................................................... 44 Summary of the Literature............................................................................. 45 III. METHOD ...................................................................................................... 48 x Participants and Design.................................................................................. 48 Task and Apparatus........................................................................................ 50 Task Description ................................................................................ 50 Starting Position................................................................................. 51 Test Apparatus: Work Station............................................................ 52 Test Apparatus: Simulated Prosthetic Device.................................... 52 Kinematic Measurement Apparatus................................................... 55 Procedures.......................................................................................... 56 Data Treatment and Analysis......................................................................... 59 IV. RESULTS ...................................................................................................... 62 Acquisition .................................................................................................... 63 Movement Time 1.............................................................................. 63 Movement Time 2.............................................................................. 66 Movement Time 3.............................................................................. 67 Movement Time 4.............................................................................. 70 Total Movement Time ....................................................................... 75 Total Movement Units ....................................................................... 75 Pitch ................................................................................................... 76 Roll..................................................................................................... 82 Cereal Spilled..................................................................................... 87 Retention........................................................................................................ 87 Movement Time 1.............................................................................. 87 Movement Time 2.............................................................................. 89 Movement Time 3.............................................................................. 89 Movement Time 4.............................................................................. 89 Total Movement Time ....................................................................... 93 Total Movement Units ....................................................................... 93 Pitch ................................................................................................... 93 Roll..................................................................................................... 94 Cereal Spilled..................................................................................... 94 Session 1 and 2 Manipulation Check Comments .......................................... 99 Impact of Verbal Reminders.......................................................................... 99 Debriefing Comments Following the Retention Session............................... 100 Group Comparisons Across Sessions ............................................................ 100 V. DISCUSSION................................................................................................ 104 xi Overall Findings............................................................................................. 104 Conclusions.................................................................................................... 113 Recommendations for Further Research........................................................ 113 REFERENCES .......................................................................................................... 115 APPENDICES ........................................................................................................... 125 Appendix A: Informed Consent Form......................................................... 126 Appendix B: Script Accompanying Video Demonstrating How To Use The Prosthetic Simulator .................................. 129 Appendix C: Kinematic Data For Each Session.......................................... 131 Appendix D: ANOVA Summary Tables..................................................... 159 xii LIST OF TABLES Table 1 Summary of Previous Studies Comparing Groups with an External Versus Internal Focus of Attention ........................................... 17 Table 2 Prosthetic Training Schedule ................................................................... 35 Table 3 Movement Time 1 (M/SD) for Session 1 (Values are in milliseconds)..................................................................... 64 Table 4 Movement Time 1 (M/SD) for Session 2 (Values are in milliseconds)..................................................................... 65 Table 5 Movement Time 2 (M/SD) for Session 1 (Values are in milliseconds)..................................................................... 68 Table 6 Movement Time 2 (M/SD) for Session 2 (Values are in milliseconds)..................................................................... 69 Table 7 Movement Time 3 (M/SD) for Session 1 (Values are in milliseconds)..................................................................... 71 Table 8 Movement Time 3 (M/SD) for Session 2 (Values are in milliseconds)..................................................................... 72 Table 9 Movement Time 4 (M/SD) for Session 1 ................................................ 73 Table 10 Movement Time 4 (M/SD) for Session 2 (Values are in milliseconds)..................................................................... 74 Table 11 Total Movement Time (M/SD) for Session 1 (Values are in milliseconds)..................................................................... 77 Table 12 Total Movement Time (M/SD) for Session 2 (Values are in milliseconds)..................................................................... 78 Table 13 Total Movement Units (M/SD) for Session 1 ......................................... 80 xiii Table 14 Total Movement Units (M/SD) for Session 2 ......................................... 81 Table 15 Pitch (M/SD) for Session 1 (Values are in degrees)................................ 83 Table 16 Pitch (M/SD) for Session 2 (Values are in degrees)................................ 84 Table 17 Roll (M/SD) for Session 1 (Values are in degrees) ................................. 85 Table 18 Roll (M/SD) for Session 2 (Values are in degrees) ................................. 86 Table 19 Movement Time 1 (M/SD) for Retention (Values are in milliseconds)..................................................................... 88 Table 20 Movement Time 2 (M/SD) for Retention (Values are in milliseconds)..................................................................... 90 Table 21 Movement Time 3 (M/SD) for Retention (Values are in milliseconds)..................................................................... 91 Table 22 Movement Time 4 (M/SD) for Retention (Values are in milliseconds)..................................................................... 92 Table 23 Total Movement Time (M/SD) for Retention (Values are in milliseconds)..................................................................... 95 Table 24 Total Movement Units (M/SD) for Retention ......................................... 96 Table 25 Pitch (M/SD) for Retention (Values are in degrees)................................ 97 Table 26 Roll (M/SD) for Retention (Values are in degrees)................................. 98 xiv LIST OF FIGURES Figure 1 Diagram of Task and Axes of Rotation ................................................... 11 Figure 2 Training Prosthesis used by Lake (1997)................................................. 34 Figure 3 Emergence of Differential Activation in the Primary Motor Cortex Evoked by the Trained (left) Compared to the Untrained (right) Sequence following Three Weeks of Practice ......................................... 41 Figure 4 Hand Elongated to the Tip of the Tool .................................................... 42 Figure 5 Cortical Loops Involved with Increasingly Complex Movement............ 43 Figure 6 Participant Seated at Work Station with Cup, Bowl, and Plate Arrangement ......................................................... 50 Figure 7 Contact Switches and Axes Orientation .................................................. 53 Figure 8 The Prosthetic Simulator.......................................................................... 54 Figure 9 The Motion Monitor Version 6 Electromagnetic Tracking System ........ 56 Figure 10 Group x Session Interaction for MT1 ...................................................... 66 Figure 11 Session x Trial Interaction for MT2......................................................... 70 Figure 12 Session x Trial Interaction for TMT ........................................................ 79 Figure 13 Session x Trial Interaction for TMU........................................................ 82 Figure 14 Amount of Cereal Spilled for Each Group Across Sessions.................... 101 Figure 15 Total Movement Time for Each Group Across Sessions......................... 102 Figure 16 Plate Pitch for Each Group Across Sessions............................................ 102 Figure 17 Plate Roll for Each Group Across Sessions............................................. 103 xv Figure 18 Total Movement Units for Each Group Across Sessions ........................ 103 1 I. INTRODUCTION An important question in motor learning concerns where attention should be focused when learning a new task. Should performers focus their attention internally on their movements and technique when executing a motor skill, or externally on the outcome of the skill? The majority of the literature dealing with this subject suggests that an external (usually visual) focus of attention produces better results than an internal (usually proprioceptive) focus of attention. In Wulf and Prinz?s (2001) review of the literature regarding attention to movement effects, they found that, in general, directing performers? attention to the effects of their movements (external focus of attention) appeared to be more beneficial than directing attention to the movements themselves (internal focus of attention) when learning new skills. At the end of the review they concluded that ?learning can be greatly enhanced if references to the performers? movements are avoided as much as possible, and if their attention is instead directed to the desired movement effect? (p. 657). Wulf and Prinz (2001) suggest that one advantage of focusing attention on the movement effect is that it allows ?unconscious processes? to take control, thus resulting in enhanced performance and learning. The common coding theory (Prinz, 1992) suggests that actions should be more effective if they are planned in terms of their intended outcome, rather than in terms of the specific movement patterns. Furthermore, 2 the ?constrained action hypothesis? (Wulf, McNevin, & Shea, 2001) suggests that when individuals are asked to adopt an internal focus, they try to consciously control their movements. This conscious control inadvertently disrupts the automatic control processes, and hinders effective movement. Related to this, the authors suggest that automatic control processes can more effectively regulate movements when an external focus is adopted, because this frees up the conscious mind to attend to other aspects of performance. However, the literature is not unanimous in supporting an external focus of attention when learning and performing a motor task. Perkins-Ceccato, Passmore, and Lee (2003) explored the role of attentional focus as a function of skill. They examined the influence of internal and external attention instructions on the performance of a pitch shot by golfers who were either highly skilled (mean handicap = 4) or low skilled (mean handicap = 26). Similar to previous findings by Wulf and others, the authors found that highly skilled golfers performed better with external attentional focus instructions than with internal attentional focus instructions. However, the low-skill golfers performed better with the internal focus instructions. In another golfing study by Black (2004), novices were taught how to perform a pitch shot with either internal or external focus instructions. Initial task performance data supported the findings of Wulf and others; however, as the golfers practiced the task over a course of nine weeks, the internal focus golfers eventually outperformed the external focus group. Black theorized that the internal focus group initially had a decrement in performance because they were focusing on proper technique while the external focus group was not. He suggested that once the 3 more biomechanically efficient golf swings were mastered by the internal focus group, their performance improved. An area of attentional focus research that has been neglected concerns disabled or rehabilitating participants. The individuals in all of Wulf?s research were typically able- bodied young adults no older than 25. The participants generally learned tasks that are sports-related, such as skiing (Wulf, H??, & Prinz, 1998), golf (Wulf, Lauterbach, & Toole, 1999), tennis (Maddox, Wulf, & Wright, 1999), or a basketball lay up (Wulf, Eder, & Parma, in press). While other studies focused on balance (Totsika & Wulf, 2003; Wulf, McNevin, & Shea, 2001), they did not explore the concept of re-learning an activity, as would commonly be the case for individuals undergoing occupational therapy. The literature as a whole contains experiments that study learning novel tasks, or elite performance of sport skills, as opposed to rehabilitating a skill that was lost due to injury or sickness. In the field of occupational therapy, while studies have explored the use of ecologically relevant items rather than simulations?for example, using a knife rather than a simulated or visualized chopper to cut mushrooms (Wu, Trombly, Lin, & Tickle-Degnen, 1998)?only a study by Fasoli, Trombly, Tickle-Degnen, and Verfaellie (2002) has focused on the impact of attentional focus instructions on rehabilitation. In the study by Fasoli et al. (2002), 16 persons with stroke who were able to perform functional reaching tasks were age-matched with 17 adults without neurological impairment. Three tasks were randomly performed: removing a can from a shelf, putting an apple into a basket, and moving a coffee mug onto a saucer. Full instructions that provided information about the task goal and focus of attention were given before the first trial of each task condition. Participants performed 8 trials under each task-condition 4 combination for a total of 48 reaches. Results of the study showed that participants with and without stroke displayed significantly shorter movement time and greater peak movement velocity during all three tasks when given externally focused instructions versus internally focused instructions. The evidence from this study suggests that internally focused instructions may impair motor performance during therapy by contributing to less efficient and less forceful reach in persons with stroke and also in healthy older adults. Although occupational therapists around the country teach motor skills on a daily basis, there has been little research exploring the best way to teach these skills. Anecdotally, many therapists tend to focus on the involved limb or body part being rehabilitated. For example, if a patient is learning to use an upper extremity prosthesis, most therapists tend to focus on the quality of the prosthesis? movement, and have the patient focus on this internally-oriented matter. Therefore, it is not unreasonable to suppose that much of the feedback therapists provide is internally focused, and based on Fasoli et al.?s (2002) findings, may actually be hindering recovery. Interestingly, some therapists have relied upon videotape as a means of providing feedback. This, too, has been shown to be detrimental (Ross, Bird, Doody, & Zoeller, 1985). In the United States today, almost 100,000 people are affected by upper extremity amputations (Wallace, Trujillo, Conner, Anderson, & Weeks, 2004). It is estimated that only forty percent of these individuals use prosthetic arms or hands due to factors such as restricted function and flexibility of a prosthesis (Frey, Carlson, & Ramaswamy, 1995). Wallace et al. (2004) found that nearly half of all individuals with prosthetics are unable to use their prostheses effectively in performing an array of daily tasks, and some do not 5 use them at all (Wallace, Anderson, Anderson, Mayo, Nguyene, & Ventre, 1999). This high rate is often due to the delay in fitting for a prosthetic, thereby hindering prompt and necessary training (Wallace et al., 2004). Weeks, Anderson, and Wallace (2003) reported that upper-extremity amputees interviewed over a year after amputation conveyed a strong desire for functional prosthetic training. Wallace et al. (2004) further noted that the style of training offered to the amputee plays an important role in promoting optimal functioning. It is therefore imperative that the training provided for amputees to acquire the necessary motor skills must begin as soon as possible and be highly effective, utilizing current, evidence-based research (Weeks, Anderson, & Wallace, 2003). The type of instructions and feedback provided to the amputation patient has a significant impact on whether attention is directed internally, to body movements, or externally, to the resulting outcome. Thus, therapists have an important role in phrasing and relaying instructions, as well as feedback, in order to induce an external focus within the patient (Wulf & Prinz, 2001). Several studies confirm this finding; instructions that elicit focus on the achievement of the task or the desired outcome, as opposed to the necessary physical movements required for mastery, are far more effective for skill acquisition (McNevin, Wulf, & Carlson, 2000; Shea & Wulf, 1999; Wulf & Prinz, 2001). Accordingly, instructions that are based on goal achievement could be given to upper- extremity amputees when learning to perform a motor task with their prosthesis. To date, there has been no research investigating the effect of internally or externally focused instructions on upper extremity amputees? prosthetic training. Therefore, this study explored the impact of internally or externally focused instructions on motor learning and movement quality of simulated upper extremity amputees. 6 Statement of the Purpose The purpose of this study was to examine the effects of externally focused (task related) versus internally focused (movement related) instructions on simulated upper extremity amputees? movement kinematics when learning a novel and ecologically relevant functional movement task. While motor learning and occupational therapy studies have investigated the impact of externally and internally focused instructions on motor learning and joint kinematics, none have specifically studied the influence of internal or external focused instructions on amputees who seek to learn how to use a prosthetic device. Furthermore, many of the motor learning studies involving amputees (or simulated amputees) have not investigated the more complicated movements that are actually required to independently function in daily life; rather, tasks include actions such as picking up a fiberglass dowel (Wallace et al., 1999), flipping a toggle switch (Weeks, Wallace, & Anderson, 2003), or lifting weights in a single plane (Wallace et al., 2002). Therefore, the proposed study would broaden the variety of tasks examined in a research laboratory setting. Finally, there may be implications for the fields of occupational and physical therapy. Because there have not been any studies to date that examine the effect of internally or externally focused instructions on motor learning outcomes for amputees, this study may contribute meaningful information to therapists who could use these findings to more effectively communicate instructions that foster the outcomes their patients desire. 7 Hypotheses The following hypotheses, based on retention test performance, were made for this study: 1. Movement time will be faster for the external focus group than for internal focus and control groups for each of the following subtasks: 1. Lift the prosthetic simulator off a start switch and reach forward to pick up a cup of cereal; 2. Lift the cup of cereal with the simulator and pour the cereal into a bowl, place the empty cup down on its original spot, and initiate picking up the bowl; 3. Pick up the bowl and place it on a plate; 4. Pick up the plate and bowl and transfer them over a 3.5 cm high barrier, without spilling the contents, onto a target area. 2. Movement organization for the task, as defined kinematically by the total number of movement units, or acceleration changes of the wrist joint center, will be most efficient for the external focus group. 3. Movement stability in subtask four of hypothesis one, as defined kinematically by the amount of pitch and roll during transfer of the plate, will be greatest for the external focus group. 4. The amount of cereal spillage will be least for the external focus group. 8 Delimitations This study was conducted during the Spring 2006 semester at Auburn University in Auburn, AL. Thirty participants from the undergraduate population volunteered for this study in exchange for extra course credit. Only right hand dominant participants were accepted for this study. Participants were required to attend three 15-minute sessions to perform an upper extremity motor learning task involving the use of a simulated transradial upper extremity prosthesis with their left upper extremity. Participants completed 10 trials of the task during each session with the goal of mastering use of the prosthetic simulator. The principal dependent measures were movement time, movement units, amount of cereal dropped, and pitch and roll of the plate during transport of the bowl of cereal during the last phase of the task. Assumptions It was assumed that participants were motivated to perform at their best, and that they were not mentally or physically fatigued to the point where performance was negatively affected. It was assumed that participants understood the task instructions provided during the experiment, and that they adopted the type of attentional focus encouraged by the instructions. It was also assumed that participants had not used any drugs or medications that affected their performance. 9 Limitations of the Study The principal limitations in this experiment were: 1. No formal mechanism was employed to determine whether the participants focused internally or externally throughout the experiment as instructed. Since the adoption and maintenance of internal or external focus throughout the entire task may have been inconsistent across groups, one cannot assume that instructions were continually followed throughout the experiment. A post-participation interview addressed this concern, but it is uncertain whether internal focus or external focus can be reliably determined in this way. 2. The simulated prosthesis produced added limb length and weight inconsistent with an actual transradial prosthesis. Because the participants? forearms and hands were intact rather than amputated, the extended length and increased weight of the experimental upper extremity may have impacted joint kinematics and motor planning. These factors may have produced results that do not reflect the actual movement patterns of true transradial amputees. 3. The cant, or angle of the terminal device, was optimally prepositioned before the experiment to allow for the most efficient angle of approach during the task. While this manipulation provided each participant with the same initial advantage, it detracted from the realism of having to perform this aspect of the task in an actual situation. 4. Because this study used simulated rather than actual amputees, the results of this study may not be generalizable to the rehabilitation of upper extremity transradial amputation patients. 10 Definition of Terms External Focus of Attention ? Attention that is focused on the position of the cup, bowl, and plate during each part of the task. External focus of attention is directed to the effects of movement, and feedback is often visual. Internal Focus of Attention ? Attention that is focused on maintaining an efficient, balanced position of the shoulder, elbow and wrist as the prosthesis is moved during each part of the task. Internal focus of attention is directed to the movements themselves, and feedback is often proprioceptive. Movement Time 1 (MT1) ? The time from the initial starting movement until the cup of cereal is lifted off the table. Movement Time 2 (MT2) ? The time from lifting the cup of cereal off the table, pouring the cereal into a bowl, placing the cup down on its original location, and lifting the bowl of cereal off the table. Movement Time 3 (MT3) ? The time from lifting the bowl of cereal off the table, placing the bowl on a plate, and lifting the plate. Movement Time 4 (MT4) ? The time from lifting and moving the plate and bowl of cereal over a 3.5 cm barrier to placing them on a designated location on the table. Movement Units ? A kinematic description of the number of zero crossings of the acceleration profile which correlates to the smoothness of a movement pattern. A single movement unit is one positive acceleration phase and one negative acceleration phase, or one zero crossing of the acceleration trace (Fetters & Todd, 1987). In this experiment, movement units were defined via two mechanisms. The first defined the onset of a movement as the point when the velocity exceeded 50 mm/s for at least 200 ms. Then, within that movement onset, accelerations were defined as changes of 5 mm/s 2 for at least 20 ms. This definition of movement unit is consistent with that provided by Fasoli et al. (2002). Pitch ? The angular deviation of the plate about the Y axis as it was moved in the horizontal plane, in standard deviation of degrees (see Figure 1). Roll ? The angular deviation of the plate about the X axis as it was moved in the horizontal plane, in standard deviation of degrees (see Figure 1). Total Movement Time ? The amount of time required for completion of the task, from initial movement where the prosthesis is lifted off a start switch until task completion where the plate and bowl are placed on an end target location. cup bowl plate 3.5 cm high barrier Start MT 1 MT 2 MT 4 MT 3 Stop x y Figure 1. Diagram of task and axes of rotation. 11 12 II. REVIEW OF LITERATURE The purpose of this study was to investigate the effects of externally focused (task-related) and internally focused (movement-related) instructions on motor learning in a simulated rehabilitation setting. This chapter presents a review of literature on the topic of attentional focus and motor learning, and is divided into the following sections: (a) attentional focus, (b) attentional focus as it relates to occupational therapy treatment, (c) upper extremity amputee training studies, and (d) brain plasticity, movement complexity, and motor planning. The end of the chapter draws some conclusions on the role verbal instructions play in the learning of novel motor tasks, and how attentional focus impacts this learning. Attentional Focus A question currently being explored in motor learning concerns where attention should be focused when learning a new task. In Wulf and Prinz?s (2001) review of the literature regarding attentional focus studies, they found that, in general, directing performers? attention to the effects of their movements (external focus of attention) appeared to be more beneficial than directing attention to their own movements (internal focus of attention) when learning new movements. Wulf and Prinz concluded that learning can be greatly enhanced if references to the performers? movements are avoided 13 as much as possible, and if their attention is, instead, directed externally to the desired movement effect. While much of the literature dealing with this subject suggests that adopting an external (usually visual) focus of attention consistently produces better results than an internal (usually proprioceptive) focus of attention, some researchers have obtained results that do not fully agree with this conclusion, and instead suggest that skill level may determine the most effective attentional focus strategy (Perkins-Ceccato, Passmore, & Lee, 2003). A relatively early study by Singer, Lidor, and Cauraugh (1994) explored what a person should think about while attempting to perform a movement skill. The authors noted that expert performers, after doing well at their chosen task, often reported that they were unaware of what they were doing at the time. With this in mind, they assigned 64 university students to one of four groups, (1) awareness, (2) non-awareness, (3) five step approach, and (4) control group (no instruction strategy). The awareness group focused on the techniques of how they moved, while the non-awareness group focused primarily on the effects of their movements. The five step approach includes the following steps: prepare for the act, image, focus on a meaningful cue, execute with a quiet mind, and evaluate the act if time permits. The task was to perform a key pressing sequence in a proper order. The task performance was then timed, and reaction time was also measured. Results indicated that participants in the five step approach group and the non-awareness approach group (synonymous with external focus) performed significantly better on both measures than either the control group or the awareness (internal focus) group. Instructions are a primary means by which experimenters control how performers focus their attention when learning a new task. Accordingly, several studies have 14 explored whether instructions directing attentional focus have any impact on motor control performance. In a study by Wulf, Shea, and Park (2001), participants were required to balance on a stabilometer. They were instructed to place their feet on the platform so that the tip of each foot touched an orange marker. The task was to keep the platform in balance, on true horizontal, as long as possible during a 90 second trial, and focus either on their feet (internal focus) or on the orange marker (external focus). Results suggested that an external focus produced higher frequency adjustments that led to more efficient balance as compared to the internal focus group. In a study investigating instructional preferences, Wulf, H??, and Prinz (1998, experiment 1) manipulated the attentional focus of participants attempting to learn slalom-type movements on a ski simulator. While one group of participants was asked to focus on their feet (internal focus), another group was asked to focus on the force exerted on the wheels of the platform, which were directly under their feet (external focus). Finally, there was a control group that was not given instructions. Results showed that the external focus group demonstrated more effective learning than did either the internal focus or control groups. Interestingly, the group that received no instructions at all performed more effectively than the group that received internally focused instructions. Many studies have explored how attentional focus impacts postural control (McNevin & Wulf, 2002; Riley, Stoffregen, Grocki, & Turvey, 1999; Wulf, Mercer, McNevin, & Guadagnoli, 2004; Wulf, Shea, & Park, 2001; Wulf, Weigelt, Poulter, & McNevin, 2003). These studies have consistently shown that maintaining an external attentional focus while performing a motor task contributes to a more efficient use of movement resources and less postural sway. Specifically, the study by Wulf, Mercer, 15 McNevin, and Guadagnoli (2004) examined the influence that attentional focus on either a postural or a suprapostural task had on the performance of each task. Participants stood on an inflated rubber disk and held a pole horizontally. All participants performed under four attentional focus conditions. The two postural tasks were: external (focused on the disk) or internal (focused on the feet). The two suprapostural tasks were: external (focus on the pole) and internal (focus on the hands). Results showed that, compared to an internal focus, focusing externally on either task resulted in reduced postural sway and enhanced postural stability. Furthermore, if the suprapostural task was made salient, then instructions to focus externally (on the pole) resulted in greater postural stability than did instructions to focus internally on the hands. Two studies have explored how attentional focus strategies affect either brain wave and heart rate activity or muscle activity (EMG). In Radlo, Steinberg, Singer, Barba, and Melnikov?s (2002) study, novice dart throwers used an ?expert like? (external focus) strategy to see if it would positively influence their performance. The effects of internal versus external focus on electrocortical activity and heart rate were examined. Consistent with previous findings, results showed that the external focus group performed with fewer errors than the internal focus group. Psychophysiologically, the magnitude of electroencephalogram (EEG) alpha brain wave activity was significantly lower for the external focus group compared to the internal focus group. Heart rate results showed that participants using the external focus strategy experienced a decrease in heart rate immediately before release of the dart, whereas the internal focus strategy group experienced an increase in heart rate. Together, these findings suggested that an external focus strategy created EEG and heart rate patterns that were ?more ideal? when compared 16 to the ideal EEG and heart rate patterns of expert dart throwers. In Vance, Wulf, Tollner, McNevin, and Mercer?s (2004) study, an integrated EMG (iEMG) was used to determine whether external versus internal focus differences would manifest themselves at the neuromuscular level. In two experiments, participants performed biceps curls while focusing on the movements of the curl bar (external focus) or their arms (internal focus). In the first experiment, movements were performed faster, and therefore more efficiently, under external rather than under internal focus conditions. In addition, iEMG activity was reduced when performers adopted an external focus. In the second experiment, movement time was controlled through the use of a metronome, and iEMG activity was again reduced under external focus conditions. The authors suggest that reduced iEMG activity indicates a more effective and efficient use of motor recruitment resources. Researchers examined what performers should think about or imagine while mentally practicing a golf putt in a study by Lutz, Landers, and Linder (2002). Participants were urged to have either a form focus of attention or an outcome focus of attention. In one group, form focus of attention (synonymous with internal focus of attention) was listed as one of the biomechanical elements required for successful putting performance. These ?form? elements included paying attention to stance, ball position, keeping the body and head still during the putt, and arm position while executing the putt. In the other group, outcome focus of attention (synonymous with external focus of attention) was on the path of the ball as it rolled toward the hole. The findings showed that participants who focused their attention on the outcome while imaging performed better than those who focused on their putting form as they putted an actual golf ball. 17 Finally, evidence suggests that significant group differences can be found between external and internal focus of attention groups more often in retention or transfer of experimental tasks than in practice (Wulf, McNevin, & Shea, 2001). Table 1 provides a list of studies and the findings in task practice and in task retention or transfer. Table 1 Summary of Previous Studies Comparing Groups with an External Versus Internal Focus of Attention Significant group differences Task In practice In retention/ transfer Maddox et. al. (2000, Experiment 1) tennis backhand yes yes Maddox et. al. (2000, Experiment 1) tennis backhand no yes Shea & Wulf (1999) stabilometer no yes Wulf, McConnel, Gartner & Schwarz (2000, Experiment 1) Volleyball serve yes yes Wulf, McConnel, Gartner & Schwarz (2000, Experiment 2) soccer yes yes Wulf, Shea & Park (in press, Experiment 1) stabilometer no yes Wulf, Shea & Park (in press, Experiment 2) stabilometer no yes Wulf, H?B, & Prinz (1998, Experiment 1) Ski-stimulator yes yes Wulf, H?B, & Prinz (1998, Experiment 1) Ski-stimulator no yes Wulf, Lauterbach, & Toole (1998 golf yes yes Wulf, McNevin, & Shea (2001). 18 Competing Evidence: Skill Level and Attentional Focus Theories of skill acquisition (Anderson, 1982; Fitts & Posner, 1967) suggest that individuals pay attention to different things during the process of mastering a new movement, and that there are stages of skill development. For novice performers, skill execution requires that attention be paid to each component of the motor act. During this cognitive stage of development, it is assumed that skill execution depends on a set of unintegrated control structures that must be held in working memory and attended to in a step-by-step fashion. During this stage, the memory and attention requirements typically produce slow, error-prone movements. Eventually, expertise develops through practice, and the highest stage of skill is reached (called the procedural or autonomous stage). As procedural knowledge develops, neither conscious step-by-step control of motor execution nor working memory and attention are required. Therefore, it is theorized that the attentional mechanisms involved in the execution of a sensorimotor skill change as expertise develops. In a discussion on dexterity, Bernstein (1996) suggested that an external focus of attention might be more beneficial for skilled athletes than less skilled athletes because the level of automation is different. Bernstein argued that motor skills (or the components of motor skills) are more highly automated in expert athletes than non-experts. An internal focus of attention, Bernstein argued, would essentially revert the athlete to a mode of control associated with less skill, consequently disrupting the current mode of control. Therefore, according to Bernstein, an internal focus of attention would be more detrimental to a skilled versus an unskilled athlete. Interestingly, some of the attentional focus literature challenges this idea. 19 Perkins-Ceccato, Passmore, and Lee (2003) studied the role of attentional focus as a function of skill. They examined the influence of internal and external attention instructions on the performance of a pitch shot by golfers who were either highly skilled (mean handicap = 4) or low skilled (mean handicap = 26). Ten golfers in each skill group pitched a golf ball as close as possible to a pylon that was placed various distances from the golfer. Results of the study showed an interaction between skill and focus of attention instructions for variability in performance. Similar to previous findings, the authors found that highly skilled golfers performed better with external attentional focus instructions but the low-skill golfers performed better with internal focus instructions. A study by Beilock, Carr, MacMahon, and Starkes (2002) also explored the relationship between attentional focus, skill level, and sensorimotor performance. The authors conducted two experiments. The first experiment investigated how experienced golfers putted under dual-task (external focus) conditions designed to distract their attention from putting, and under skill-focused conditions that encouraged attention to be focused on step-by-step putting performance. In this experiment, the authors found that the dual-task condition putting was more accurate. In the second experiment, right footed novice and experienced soccer players dribbled through a slalom course under dual-task (external focus) or skill-focused (internal focus) conditions. When using their dominant right foot, expert soccer players again performed better in the dual-task condition. However, when using their less proficient left foot, experts performed better in the skill- focused (internal) condition. Novices performed better under skill-focus conditions regardless of foot. The authors therefore found that novices and less-proficient expert 20 performances benefit from internal focus, whereas high-level performance is impaired by this approach. In a related study by Gray (2004), a simulated baseball batting task was used to compare the relative effects of attending to extraneous information (a tone frequency) and attending to skill execution (direction of bat movement) on performance and swing kinematics. Furthermore, the study evaluated how these effects differ as a function of expertise in skilled and novice participants. The extraneous (external focus) dual task degraded batting performance in novices, but had no significant effect on experts. The skill-focused dual task (internal focus) increased batting errors and movement variability for experts but had no significant effect on novices. For expert batters, accuracy in the skill-focused task was inversely related to the current level of performance. Expert batters were significantly more accurate in the skill-focused dual task when placed under pressure. Gray suggests that these findings indicate that the attentional focus varies substantially across and within performers with different levels of expertise, and that movement through Fitts and Posner?s (1967) three stages of learning may not be so unidirectional. Black (2004) explored how internal versus external focus instructions impact learning a golf chip shot. In this two-experiment study, the first experiment replicated Wulf, Lauterbach, and Toole (1999), where participants performed a golf chip shot 80 times in one session, and focused either externally on the club, or internally on arm action. Like Wulf?s study, Black found that in the single session experiment, the external focus group performed better than the internal focus group. Black?s second experiment divided novice golfers into two groups, one receiving internal focus instructions, and the 21 other external focus instructions. However, unlike the studies by Wulf which used brief one or two day practice sessions, practice in this second experiment was extended to 11 sessions of 30 chip shots each. Black found no difference between internal and external focus during practice performance sessions, but the internal focus group was superior to the external focus group on a delayed retention test. Additionally, Black found that, early on, the external attentional focus group outperformed the internal focus group. However, during the eighth of the 11 sessions, the internal focus group began performing as well as the external focus group. Black attributed these findings to a theorized progressive internalization of the proper golf swing biomechanics, and that the internal focus group was able to perform as well as the external focus group once these motor programs had been integrated (Black, personal communication, June 12, 2004). Taken together, these studies provide an alternative to the view that adopting an external focus of attention produces superior motor learning results. At present, there is a schism between the findings of the studies largely conducted by Wulf, and the studies produced by the authors in this section. At present, these findings appear incompatible, and further research is required to determine whether adopting an external focus of attention is beneficial primarily for expert performers, or for both novices and experts. Attentional Focus Theories Wulf and Prinz (2001) suggest that one advantage of focusing attention on the movement effect is that it allows ?unconscious processes? to take control, thus resulting in enhanced performance and learning. The common coding theory (Prinz, 1992) suggests that actions should be more effective if they are planned in terms of their intended outcome, rather than in terms of the specific movement patterns. Furthermore, 22 the ?constrained action hypothesis? (Wulf, McNevin, & Shea, 2001), suggests that when individuals adopt an internal focus, they try to consciously control their movements. This conscious control inadvertently disrupts the automatic control processes and hinders effective movement. The authors suggest that automatic control processes can more effectively regulate movements when an external focus is adopted because this frees up the conscious mind to attend to other aspects of the environment. Prior to the development of the above theories, Masters and colleagues (Masters, 1992; Masters, Polman, & Hammond, 1993) proposed that attention to high-level skills results in their ?breakdown,? in which the compiled real time control structure of a skill is broken down in a sequence of smaller, separate, independent units?similar to how performance may have been organized early in learning. Once broken down, each unit must be activated and run separately, which slows performance and, at each transition between units, creates an opportunity for error that was not present in the ?chunked? control structure. Researchers have proposed that this process of breakdown contributes to poor performance of well-learned skills in high-pressure situations (Beilock & Carr, 2001; Lewis & Linder, 1997). Attentional Focus and Occupational Therapy Few attentional focus studies have explored how internal or external focus impacts disabled or rehabilitating individuals. Generally, the participants in the attentional focus literature are able-bodied young adults no older than 25. They are often required to learn a task that is sports-related, such as skiing (Wulf, H??, & Prinz, 1998), golf (Wulf, Lauterbach, & Toole, 1999), tennis (Maddox, Wulf, & Wright, 1999), or a 23 basketball lay up (Wulf, Eder, & Parma, in press). However, there are examples from the occupational therapy literature where instructions are used to direct a person?s attention, influence sensory awareness, and establish goals for a particular motor action (Brooks & Watts, 1988; Carr & Shepherd, 1998). For example, a study by Wulf, Landers, Wallman, and Guadagnoli (2003), explored the impact of attentional focus instructions on patients with Parkinson?s disease. The results indicated that an external focus of attention attenuated balance impairment in patients with Parkinson?s disease. In the field of occupational therapy, while studies have explored the use of ecologically relevant items rather than simulations?for example, using a knife to cut mushrooms rather than a simulated or visualized chopper (Wu, Trombly, Lin, & Tickle- Degnen, 1998)?few studies have focused on the impact of instructions on motor performance. Specifically, Spatt and Goldenberg (1997) examined the effect of instructions on motor performance in persons with cerebrovascular accident (also known as CVA or stroke). In this experiment, participants with and without limb apraxia were asked to perform a novel task with their unaffected arm under two instruction conditions. Apraxia is defined as the total or partial loss of the ability to perform coordinated movements or manipulate objects in the absence of motor or sensory impairment. In the first condition, externally focused instructions directed attention toward the task goal, which was to depress one, two, or three illuminated keys simultaneously with any fingers as quickly as possible. In the second condition, internally focused instructions required participants to quickly depress the lit keys with only the fingers indicated by a visual model of a hand, thereby drawing attention to specific motor responses. Analysis of only the trials that had been performed identically in both conditions revealed that persons 24 with and without CVA demonstrated significantly shorter reaction time and fewer movement errors under the external-focus condition. After ruling out alternative hypotheses related to variations in the cognitive and perceptual demands across conditions, the authors concluded that externally focused instructions, directed toward the task goal, positively influenced motor performance in the arm ipsilateral to the side of the stroke lesion. However, it appears to this writer that there are flaws in this study. For example, the increased motor planning demands of the second condition, as introduced by the visual model of the hand, would theoretically increase the time required to develop an effective motor program, thereby increasing reaction time, and thus confounding the results of the study. Also, there was no control group in the study. A study by Fasoli, Trombly, Tickle-Degnen, and Verfaellie (2002) addressed the impact of attentional focus on functional reach in persons with and without CVA. In this study, 16 persons with stroke who were able to perform functional reaching tasks were age-matched with 17 adults without neurological impairment. Three tasks were randomly presented: removing a can from a shelf, putting an apple into a basket, and moving a coffee mug onto a saucer. Full instructions that provided information about the task goal and focus of attention were given before the first trial of each task condition. Participants performed 8 trials under each task-condition combination for a total of 48 reaches. Results of the study indicated that both groups displayed significantly shorter movement time and greater peak movement velocity during all three tasks when given externally focused instructions versus internally focused instructions. In the discussion, the authors conclude that: 25 The results of this study indicate that persons with and without stroke can benefit from externally focused instructions that emphasize visual information during the interaction with task objects. Therapists may find instructions that highlight relevant task affordances, such as the size or shape of the object, to enhance the automatic shaping of reach to grasp movements. The evidence from this study suggests that internally focused instructions may actually deter motor performance during therapy by contributing to less efficient (slower) and less forceful reach in persons with CVA and in older adults without neurological impairments. (p. 387-388) These findings are significant, because therapists are often engaged in helping their patients relearn motor skills. For example, a spinal cord injury patient may need to relearn basic activities of daily living such as dressing, bathing, toileting, feeding, and grooming. While occupational therapists re-teach these skills on a daily basis, there has not been any research exploring the best way to re-teach these skills. Anecdotally, many therapists tend to focus on the involved limb or body part being rehabilitated. For example, if a patient is learning to use an upper extremity prosthesis, most therapists tend to focus on the quality of the prosthesis? movement, and have the patient focus on this internally-oriented matter. Therefore, it is not unreasonable to suppose that much of the feedback therapists provide is internally focused, and based on Fasoli et al.?s findings, may actually be hindering recovery. Interestingly, some therapists have relied upon videotape as a means of providing feedback. This, too, has been shown to be detrimental because it caused the patient to attend to movement patterns rather than movement outcomes (Ross, Bird, Doody, & Zoeller, 1985). 26 Occupational therapy often uses goal-directed tasks to create positive therapeutic outcomes. This is a traditional difference between occupational and physical therapy, which relies upon exercise as its primary treatment modality. For example, an occupational therapist might select an activity to perform which has shoulder flexion embedded in it, whereas a physical therapist would simply prescribe so many sets of shoulder flexion exercises to bring about shoulder strengthening. These different approaches have interesting implications when viewed from an attentional focus perspective, since exercises tend to be more internally focused and activity tends to be goal-directed, or more externally focused. If this research were shown to be effective in rehabilitating subjects, a shift towards more purposeful activity would be indicated. Indeed, this has already been called for by some occupational therapists (Flynn, 1999). In summary, attentional focus studies present evidence that if individuals can direct their attention to the outcome or goal of their actions, learning is notably enhanced. Furthermore, an approach to learning that is goal-oriented demands that the patient internally solve the required movement components. This encourages focusing on achievement of the goal, as opposed to simply responding to the therapist?s instruction (May, 2003). Instruction and Feedback The style of instructions and feedback provided to the patient have a great impact on whether attention is directed internally, to body movements, or externally, to the resulting outcome. Thus, therapists have an important role in phrasing and relaying instructions, as well as feedback in such a way as to provoke an external focus for the patient (McNevin, Wulf, & Carlson, 2000). Several studies confirm this principle; 27 instructions that elicit focus on the achievement of the task or the desired outcome, as opposed to the necessary physical movements required for mastery, are more effective for skill acquisition (Hodges & Franks, 2000; Shea & Wulf, 1999; Wulf & Weigelt, 1997). Accordingly, instructions that are based on goal achievement could be given to rehabilitation patients when learning a motor task. For example, Weeks, Wallace, and Anderson (2003) studied motor training on individuals using a simulated upper-limb prosthesis. Task achievement requires properly opening and closing the prosthetic device, which necessitates numerous internal muscle functions. Although demonstrations provided thorough instruction on using the simulated prosthesis for the participants, the study does not reveal whether attentional focus methods were incorporated into the task instructions. Such techniques could be utilized if instructions to the participant were focused solely on the task goal (McNevin, Wulf, & Carlson, 2000). The researchers did instruct the participants to sit with an upright posture and avoid awkward body motions to control the device (Weeks, Wallace, & Anderson, 2003, p. 440). Wulf, McNevin, and Shea?s (2001) research on instructions and attentional focus suggests that instructions pertaining to control of body movements can elicit an internal focus of control, and thus negatively impact skill acquisition. In a study by Hodges and Franks (2000), four groups of participants were taught a bimanual coordination movement pattern under instructions designed to manipulate attentional focus. The movement pattern was taken from the inter-limb coordination work of Kelso (1995). Three of the four groups received demonstration of the movement, while a fourth group received only goal relevant feedback. Of the three groups receiving demonstration of the movement, one received instructions directing their attention 28 towards the feedback (external), one received instructions directing their attention toward the relationship between their arm movements and the feedback (internal), and the third group received no attention-directing instructions. Results showed that the skill acquisition rate was slower for the demonstration-only group, especially when compared to the external focus group. Furthermore, these differences remained in retention. The authors concluded that movement demonstrations alone do not facilitate learning of a novel coordination task unless additional goal directed instruction is provided. Further, the authors state that: If movement demonstrations are to be provided they should be coupled with goal- focusing instruction, so that acquisition and retention performance is not adversely affected. For example, when learning to perform a chip shot in soccer, although instruction concerning how to do this shot may help in terms of movements of the hips, legs, and feet, the goal of the task should be emphasized throughout practice. Instruction or feedback that focuses on the ball trajectory, for example, where the importance of raising the ball in the air would be encouraged, could be used to direct attention appropriately. Alternatively, a physical obstacle could be implemented to encourage a goal-focus, so that the learner is aware of the necessity to clear the obstacle. (p. 866) In their review article, McNevin, Wulf, and Carlson (2000) also address instruction and attentional focus techniques. They suggest that in the latter stages of rehabilitation, as patients are relearning motor tasks that promote successful performance of purposeful activities, external focus is more beneficial. Their review of the literature indicates that internal attentional focus may initially seem to be necessary for training 29 lower-extremity amputees because the client must first learn the mechanics involved in ambulation, and instruction therefore requires an internal focus. However, the authors suggest that prompting the client to focus externally, such as with a lower-extremity amputee focusing on moving a walker or cane, results in improved skill acquisition. Researchers have also evaluated how internally or externally focused feedback affects motor learning outcomes. Feedback is a crucial component in the motor learning process, and an individual learning a task depends upon it in order to modify behavior and improve performance (May, 2003). Shea and Wulf (1999) investigated whether the effectiveness of feedback depends upon the focus of attention induced by those instructions. This study presented a stabilometer task to two groups of participants. Interestingly, the feedback presented to the participants was identical and only its interpretation was manipulated. Concurrent visual feedback consisting of the platform movements being displayed on a computer screen was provided to both groups. The internal focus group was informed that the feedback represented their own movements, whereas the external focus group was told that the feedback represented lines that were attached to the platform in front of each of the participant?s feet. There were also internal and external focus control groups that were not provided feedback but were instructed to focus on their feet or the lines respectively. Retention results showed that even though the feedback display was identical for the two feedback groups, the group interpreting the feedback as external performed better than the group interpreting it as internal. The authors also found that the concurrent feedback was generally more effective than no feedback in improving the participants? balancing ability. 30 In another feedback study, Wulf, McConnel, G?rtner, and Schwarz (2002) examined the generalizability of the external-focus feedback benefits to the learning of the overhand volleyball serve. One of the aims of this study was to replicate actual coaching conditions, where coaches generally give feedback about critical flaws in technique with the intent to improve performance by correcting errors. In the experiment, different feedback statements were selected that the authors found to be commonly used in volleyball training, and which refer to the performer?s body movements (internally focused feedback). These statements were then reworded so that they contained the same information, but now directed the participants? attention to the movement effects (external focus). After every fifth practice trial, the participant was provided with the feedback statement that was considered most suitable based on the performance during the five practice trials. Results showed that the accuracy of the serves was greatly enhanced by the external-focus, relative to the internal-focus, not only during practice, but also after a one week retention interval in a retention test without feedback. It is important to note that this was true not only for novices, but also for advanced players who had previous experience executing the overhand serve. Finally, expert raters evaluated the form of the participants during their practice sessions, and found that both types of feedback led to similar improvements in form. While not specifically designed to explore internal versus external focus and motor learning, a study by Todorov, Shadmehr, and Bizzi (1997) showed that the learning of table tennis strokes was enhanced by providing performers with concurrent feedback about the trajectory of their paddle as compared to the trajectory of an expert player (external feedback). Participants receiving this kind of feedback were more 31 accurate in hitting a target than were the participants who were provided with verbal feedback on gross errors and who practiced 50% more. Upper Extremity Amputee Studies In the United States today, almost 100,000 people are affected by upper extremity amputations (Dillingham, Pezzin, & MacKenzie, 2002; Wallace, Trujillo, Connor, Anderson, & Weeks, 2004). Males are at significantly higher risk for trauma-related amputations than females, with an incidence rate ratio of 4.94. For both males and females, risk of traumatic amputations increases steadily among those ages 85 and older. African Americans, particularly those ages 35 and higher, were generally at a higher risk than non-Blacks for trauma related amputations. Among non-Blacks, the incidence of trauma-caused amputations was essentially constant across age groups at about 7 per 100,000, except for a much lower rate at younger ages and a higher rate among those aged 75 and older (Meier, 2004). It is estimated that only forty percent of those who would benefit from the use prosthetic arms or hands use them. This is due to factors such as restricted function and flexibility of the prostheses (Frey, Carlson, & Ramaswamy, 1995). Nearly half of all individuals with prosthetics are unable to use their prostheses effectively in performing an array of daily tasks, and some do not use them at all (Meier, 1992; Wallace, Anderson, Anderson, Mayo, Nguyene, & Ventre, 1999). This high rate is often due to the delay in fitting for a prosthetic, thereby hindering prompt and necessary training. Weeks, Anderson, and Wallace (2003) reported that upper-extremity amputees interviewed over a year after amputation conveyed a strong desire for functional prosthetic training. 32 Wallace et al. (2004) further noted that the style of training offered to the amputee plays an important role in promoting optimal functioning. It is therefore imperative that the training provided for amputees to acquire the necessary motor skills must begin as soon as possible and be highly effective, utilizing current, evidence-based research (Weeks, Wallace, & Anderson, 2003). Of the amputees who choose to use upper extremity prostheses, about 90 percent use body-powered types, which are more reliable, lighter, quieter and less expensive than externally powered prostheses (Frey, Carlson, & Ramaswamy, 1995). Among body- powered prehensors, voluntary-opening (VO) control is used more widely than voluntary-closing (VC) control. In a VO prehensor, springs or elastic bands provide grip force. This is advantageous because the amputee may relax cable tension while maintaining grip. With a voluntary closing mechanism, the terminal device is open at rest. The patient uses the residual forearm flexors to grasp the desired object. This type of mechanism usually is heavier and less durable than a voluntary opening mechanism. Research suggests that amputees generally prefer VO upper extremity prostheses over VC (Davies, Friz, & Clippinger, 1970). Recently, the importance of effective prosthesis training has been highlighted for those involved in treating individuals in the military. The prevalence of upper extremity amputation due to trauma increases for the men and women of the armed forces during times of military conflicts such as the recent Operation Iraqi Freedom (OIF) and the current Operation Enduring Freedom (OEF). As of February 10, 2006, the total number of Wounded in Action from both OEF and OIF was listed at 17,338, with 8,113 not able to return to duty. Six percent of those wounded required amputations, as compared with 33 only three percent from previous wars (Springer & Howard, 2006). Those experiencing amputations require specialized care as recognized by the military, including wound management, pre-prosthetic training, as well as basic and advanced prosthetic training. Walter Reed Army Medical Center has responded to the increased need by creating a dedicated Occupational Therapy Amputee Section in August 2003, as well as developing a protocol/treatment pathway to provide an objective reproducible method for treating amputees including prosthetic training. Prosthetic Training Techniques In 1952, Berger and Graham published a seminal article on the requirements for the effective training of upper extremity amputees. These findings have withstood the test of time, and include the following recommendations: 1) the amputee should be capable of flexing the forearm through its full mechanical passive range, 2) the terminal device should reach full opening when activated with the forearm flexed to 90? and should reach at least 50% of full opening when reaching the mouth or the midsection, and 3) approximately three quarters of the amputee?s pronation and supination should be retained when the prosthesis is worn (p. 29). Additionally, instruction in the use of the prosthesis should cover training in gross prosthetic movements, training in the use of the terminal device, practice in activities of daily living, and instruction in attaching and removing the prosthesis, changing terminal devices, and general care of the appliance. Regarding teaching activities of daily living, the authors state that: Instruction and drill in the performance of daily living activities must be made meaningful by careful selection on the basis of their value and importance to the amputee. This training is concerned with the integration of individual prosthetic movements into coordinated activity patterns. It should be noted, however, that no amputee should be forced into a rigid, predetermined activity pattern. Rather, the amputee is helped through training to coordinate the functions of his device into the pattern that is most natural and satisfying to him within the framework of correct body mechanics. (p. 29) In more current research, Lake (1997) studied the effects of prosthetic training for a person using an upper-extremity prosthesis. Ten individuals without amputations were randomly assigned to either a training or nontraining/control group. Because these individuals were not amputees, they were fitted with bilateral training prostheses (see Figure 2). Figure 2. Training prosthesis used by Lake (1997). The training group was involved in a training program administered by the researcher in which the participants took advantage of various items (blocks, paper, beads, pencils, clothes and hangers) to learn how to use upper-extremity prostheses. The training required two hours per day for four days. The training schedule is shown in Table 2. 34 35 Table 2 Prosthetic Training Schedule Day One Day Three ? Pretest ? Write name/alphabet ? Tear paper ? Carry cups of water ? Use ruler ? String beads (8-mm diameter) ? Grasp/release exercises Review of peg board, books, beads and hand- to-hand from previous day. ? Pour glass of water ? Write on an envelope ? Count change ? String beads (3-mm diameter) ? Fold paper Day Two Day Four Review blocks, writing, beads and hand-to- hand from previous day. ? Fasten buttons ? Peg board activities ? Color in coloring books ? Use clothes hangers ? Manipulate notched sticks ? Turn pages in a book ? String beads (5-mm diameter) ? Place folded paper in envelope ? Take objects off shelf ? Open candy ? Block manipulation Review of counting change, beads and hand-to- hand from previous day. ? Stack blocks ? Tie a knot ? Hang clothes ? Use a tape measure ? Apply a band-aid ? Write ? Place stamps on envelope ? Eat ? Post-tests ? Additional tasks Lake (1997, p. 5). The control group received the same items and performed the same activities as the training group, but did not receive any training. For example, a method for holding a pencil that ensures minimal rotation and maximum stability was explained and 36 demonstrated to the training group, while the control group was simply provided with the pencil and paper and told to use them to the best of their ability. Participants were involved in four sessions of approximately two hours each. Pre- and post-tests determined the progress of the participants. In addition, all participants were required to complete four additional tasks to determine if the groups could apply what was practiced in the training sessions to novel situations. Lake found that the individuals who received training performed tasks in a skillful, efficient manner, exceeding the performances of the untrained group in all tasks. However, significance in efficiency was achieved only in the following tasks: folding a towel and opening an aspirin bottle (p = 0.01), and completing a dowel and washer task (p = 0.02). This suggests that, while training significantly improved performance in a few tasks, more participants are needed to reveal significant differences in learning between groups. To empirically determine the initial difficulty of using an upper extremity prosthesis, Wallace et al. (1999) evaluated novice prosthetic users engaged in a reaching and grasping task with a simulated upper extremity prosthesis. The authors showed that novice prosthesis users were nearly three times as slow and much more variable in completing the motor task compared with their anatomical hand. In the occupational therapy literature, Yuen, Nelson, Peterson, and Dickinson (1993) investigated the use of object-produced visual input in learning control of flexion and extension of an above-elbow prosthesis. Fifty-two male college students were randomly assigned to two training procedures: (a) two 1.5 minute periods in which they used a flashlight attached to the hook of the prosthesis to connect dots on paper with light, or (b) the same time periods in which they practiced moving an equally weighted 37 prosthesis, but without the light or dots. To assess motoric adaptation after training under one of the two conditions, each subject traced a continuous line through a maze with a pen attached to the hook. Deviations from the line were measured. Results showed that participants in the group training with the flashlight traced with significantly more skill than participants in the control group. Interestingly, the instructions (p. 57) for the group training with the light were as follows: ?The purpose of this study is to see how well you can learn to control the movement of the mechanical arm at the elbow joint steadily and accurately by focusing on learning to control the movement of the light beam from the flashlight? (italics added). For the control group, the instructions were: ?The purpose of this study is to see how well you can learn to control the movement of the mechanical arm at the elbow joint steadily and accurately by focusing on the movement of the mechanical arm? (italics added). Clearly, these instructions are inadvertently phrased to manipulate the attentional focus of the participants either externally or internally. These instructions, therefore, may confound the authors? conclusions that the competing explanations for their findings are limited to feedback, specificity of learning, and object affordance. Furthermore, while the suggestion that occupational therapists are urged to consider the use of objects in the training of motor skill rather than just practicing the required movement is a reasonable one based on the findings, the rationale behind it may be flawed because attentional focus was not considered as a contributing factor. Amputee Training and Motor Learning Practice Designs Motor learning theories have generated lines of research designed to determine methods for optimizing skill acquisition for upper-extremity amputees with prostheses. An emphasis on cognitive processing to promote motor learning in amputees has been the 38 focus of a recent study by Weeks, Anderson, and Wallace (2003). This study explored the use of two different practice schedules for learning to use a voluntary-close prosthetic simulator in order to determine an efficient practice schedule for learning to perform prehension skills that could then be used in clinical settings. Participants were randomly assigned to two groups for skill training, one using a random practice order, and the other using blocked practice. Each group practiced skill acquisition on two consecutive days. On the third day, a retention test and an intertask transfer test were administered. Both groups showed significant improvement in initiation time and movement time. However, in intertask transfer, the random acquisition group demonstrated significantly greater proficiency in performing the new tasks than the blocked group. In support of these findings, the authors suggest that designing practice sessions that employ increased variability during practice will enhance the learner?s cognitive effort, thus committing the task demands to memory for more effective learning and intertask transfer. In a study addressing bilateral transfer, Weeks, Wallace, and Anderson (2003) examined whether skill acquisition with one limb can improve the performance of the contralateral limb for the same task. This study found that once a task is mastered with the trained limb, the learned motor functions are generalized with respect to both limbs, resulting in successful transfer of skill. This concept has great potential for assisting in rehabilitation for upper-extremity amputees. Motor learning through use of a prosthetic simulator on the intact limb can occur long before training with the actual prosthesis begins. Wallace et al. (1999) contend that the mechanics of the simulator are similar to a normal prosthesis, and studies utilizing simulated prosthetics on able-bodied individuals can readily be applied to populations such as amputees. Weeks, Wallace, and Anderson 39 (2003) contend that prompting motor training with the prosthetic device increases the likelihood for optimal daily functioning. Results of this study also indicated that practice with a prosthetic simulator allows for bilateral transfer from either the preferred or the nonpreferred arm to the opposite arm. In a study of intermanual transfer of a novel writing task conducted on young adults without disabilities, Andree and Maitra (2002) assert that successful mastery of a skill with one hand greatly enhances future learning with the opposite hand. Furthermore, transfer of learning was independent of hand dominance. These authors also state that further research is needed to determine whether results would be similar for populations with disabilities. Wallace et al. (1999) note that although evidence exists for bilateral transfer of simple motor tasks, further research is needed to determine its effectiveness for complex tasks. Wulf and Prinz?s (2001) review notes the role of purposeful activity in eliciting greater bilateral transfer of skill. In much the same way that random practice schedules enhance learning, practicing skills in the clinic that assist the client in meeting real-world demands notably promotes learning. This technique could, therefore, assist in motor training for amputees. Wulf and Prinz further suggest that incorporating purposeful activity into training allows the patient to more effectively focus on the goal of training, and in turn, focus externally. If tasks are meaningful to patients and can be applied to daily living, their attention is focused on the meaning of the task as opposed to the required internal movements. 40 Brain Plasticity, Movement Complexity, and Motor Planning While many studies have explored areas of the brain involved with motor learning, fewer studies have focused on the dynamic neural changes that occur in the motor system during the different phases of learning. Ungerleider, Doyon, and Karni (2002) used a simple finger-opposition task in which subjects were trained and tested over the course of several weeks, and were scanned using functional MRI at weekly intervals to image their brains. The results showed that in the first scan session, performed before any training was given, a similar proportion of the contralateral primary motor cortex was activated by the execution of both sequences. However, by the fourth session, which corresponded to three weeks of daily practice, the extent of activation evoked by the trained sequence in the primary motor cortex was significantly larger compared to the extent of activation evoked by the control, untrained sequence. These results were interpreted to mean that ?long-term practice results in a gradually evolving, specific, and more extensive representation of the trained sequence of movements in the primary motor cortex? (p. 556). This evolving human motor memory is eventually transformed into a long-term trace. Furthermore, the authors noted that the change in the primary motor cortex follows more dynamic, rapid changes in the cerebellum, striatum, and other motor-related cortical areas over the course of days. It appears that the cerebellum, striatum, and other areas make short term adjustments while the primary motor cortex is forming a motor program. Figure 3 shows the change in activation of the primary motor cortex before and after a long term trace, or motor program, has been developed. Figure 3. Emergence of differential activation in the primary motor cortex evoked by the trained (left) compared to the untrained (right) sequence following three weeks of practice. From ?Imaging Brain Plasticity During Motor Skill Learning,? by L. G. Ungerleider, J. Doyon, and A. Karni, 2002, Neurobiology of Learning and Memory, 78, p. 557. Other studies consistently indicate that areas of primary somatosensory cortex that lose hand and forelimb inputs, as with trans-radial amputation, become functionally reactivated by uninjured inputs from the face and/or stump (Wall & Wu, 2002). In their review article, Wall and Wu (2002) state that several aspects of cortical functional changes have become apparent: 1) Broad concepts of temporal progressions have emerged, meaning that the timelines for cortical reorganization vary widely between individuals; 2) Cortical changes can continue from 2 ? 60+ years after amputation; 3) Chronic mapping changes can be reversed under appropriate conditions; 4) Functional changes occur in other cortical areas, including the posterior parietal, primary motor, and ipsilateral primary somatosensory areas; 5) Amputation may also cause complimentary 41 shifts in injured inputs; and 6) Cortical map reorganization may not be apparent in some amputation patients even after many years (p. 194). Event-Related Studies and Motor Pathways A review article by Maravita and Iriki (2004) discusses neurophysiological, psychological, and neuropsychological research that suggests specific neural networks hold an updated map of body shape and posture (body schema) after the use of tools that extend the reach. Their findings suggest that the area of reach covered by a tool can be incorporated into the body schema, such that the hand was elongated to the tip of the tool (see Figure 4). Figure 4. Hand Elongated to the Tip of the Tool (Maravita & Iriki, 2004). 42 Movement Complexity and Motor Pathways As movements become increasingly complex, more areas of the brain are required to perform the movement smoothly and accurately. Specifically, the parietal association area integrates touch and vision while focusing our attention during more complex acts (Vilus, 2003). Figure 5 illustrates the cortical loops involved with executing increasingly complex movements. Figure 5. Cortical loops involved with increasingly complex movement. Loop 1 is used for simple acts, like quickly regulating the pressure on a coffee cup. Area 3 signals finger position and senses pressure, and area 4 contracts individual muscles. Loop 2 is used in more complex acts like selecting a muscle synergy (determining which fingers to contract together) to lift the coffee cup. Loop 3 is used for still more complex acts like reaching for the cup (parietal association area integrates touch and vision while focusing our attention). From Vilus, T. (2003, July 11). Motor cortex. Retrieved Oct 25, 2005, from http://www.med.uwo.ca/physiology/courses/medsweb/L8Motor/M8Motor.pdf. 43 44 The motor pathways, or loops, involved with movement change in proportion to complexity. The sequence of cortical activation is as follows: pre-cingulate motor area and pre-SMA ? cingulate motor area and SMA ? posterior SMA and primary motor cortex. After this sequence, feedback is reported via the cerebellum and somatosensory cortex. As the movement becomes more complex, the parietal lobules are increasingly involved (Ball et al., 1999; Winterer et al., 2002). Visuo-Motor planning While the SMA is concerned with motor planning, the pre-SMA appears to be specifically connected with visuo-motor planning. A study by Sakai, Hirosaka, Miyauchi, Sasaki, and Putz (1999) compared pre-SMA activation in closely matched tasks that required visuo-motor associations, but varied in motor and perceptual sequence components. Activation of the pre-SMA occurred in all tasks related to visuo-motor association demands rather than sequential components. This study showed conclusively that activation of the pre-SMA has little to do with motor sequence learning. Instead, pre- SMA activation occurs in association with establishing or retrieving visuo-motor associations. In addition, attending to various features of visual stimuli was found to activate the pre-SMA. The pre-SMA showed transient activation associated with shifts of attention to visual object features (shape, color, location) in a card sorting task (Nagahama et al., 1999). Other studies have found that the pre-SMA has poor somatotopic organization and operates at a more abstract level (Picard & Strick, 2001). 45 Summary of the Literature The purpose of this review was to explore the research that has investigated how attentional focus may contribute to occupational therapy and upper extremity amputee rehabilitation, and to present recent scientific evidence explaining the mechanisms responsible for motor behavior. Several areas of attentional focus research have been studied. These include the role instructions have upon attentional focus, how feedback affects attentional focus, how attentional focus impacts motor control, the impact of attentional focus instructions on EMG results, and how attentional focus impacts brain wave patterns in imagery studies. The findings of these studies suggest that: 1) providing instructions and feedback that direct attention to the effects of movements (external focus) are more beneficial than directing attention to the movements themselves (internal focus), 2) individuals prefer external focus when learning, 3) focusing on effects that occur an intermediate distance away from the body, so that they can be distinguished from body movements, and yet, not so distant that results cannot be related to body movements, produce optimal results, 4) feedback interpreted as external is more effectively implemented than feedback interpreted as internal, 5) learners retain skills more effectively when they receive externally focused instructions, 6) iEMG patterns reflect a more effective and efficient use of motor recruitment resources when external focus strategies are used, and 7) the positive effects of external versus internal focus of attention carry over into imagined rehearsal of skills to be performed at a later time. The research in this chapter revealed that, in the United States today, almost 100,000 people have upper extremity amputations (Dillingham, Pezzin, & MacKenzie, 2002; Wallace, Trujillo, Connor, Anderson, & Weeks, 2004), and that it is estimated that 46 only forty percent of those individuals use prosthetic arms or hands due to factors such as restricted function and flexibility of a prosthesis (Frey et al., 1995). Nearly half of all individuals with prosthetics are unable to use their prostheses effectively in performing an array of daily tasks, and some have no use at all (Meier, 1992: Wallace, Anderson, Anderson, Mayo, Nguyene, & Ventre, 1999). Weeks, Anderson, and Wallace (2003) reported that upper-extremity amputees interviewed over a year after amputation expressed a clear preference for functional prosthetic training. Wallace et al. (2004) further noted that the style of training offered to the amputee plays an important role in promoting optimal functioning. Davies, Friz, and Clippinger (1970) report that voluntary opening upper extremity prostheses are generally preferred over voluntary closing. It is therefore imperative that the training provided for amputees to acquire the necessary motor skills must begin as soon as possible and be highly effective, utilizing current, evidence-based research (Weeks et al., 2003). While motor learning and occupational therapy studies have investigated the impact of externally and internally focused instructions on motor learning and joint kinematics, none have specifically studied the influence internal or external focused instructions have upon amputees who seek to learn how to use a prosthetic device. Furthermore, many of the motor learning studies involving amputees (or simulated amputees) have not investigated the more complicated movements that are actually required to independently function in daily life; rather, tasks include actions such as picking up a fiberglass dowel (Wallace et al., 1999), flipping a toggle switch (Weeks, Wallace, & Anderson, 2003), or lifting weights in a single plane (Wallace et al., 2002). 47 Therefore, the proposed study would broaden the variety of tasks examined in a research laboratory setting. The purpose of this study is to examine the effects of externally focused (task related) versus internally focused (movement-related) instructions on simulated upper extremity amputees? movement kinematics when learning a novel and ecologically relevant functional movement task. It is hypothesized that instructions that focus the attention externally will produce movement patterns that are more efficient, and that will allow participants to master usage of the simulated upper extremity prosthesis more quickly, and to retain this skill more effectively. It is expected that the performance of the external focus group will exceed that of the internal focus and control groups in this study. This study will provide information for the fields of occupational and physical therapy. Because there have not been any studies to date that examine the effects that internally or externally focused instructions have upon motor learning outcomes for amputees, this study may contribute meaningful information to therapists who could use these findings to more effectively communicate instructions that foster the outcomes their patients? desire. 48 III. METHOD The purpose of this study was to examine the effects of externally focused (task related) versus internally focused (movement related) instructions on simulated upper extremity amputees? movement kinematics when learning a novel functional movement task. This chapter presents the method of the study and includes the following sections: (a) participants and design, (b) task and apparatus, (c) procedures, and (d) data treatment and analysis. Participants and Design Thirty university students, 17 females and 13 males, ranging from age 19-26 participated in the study. Participants had no prior experience with the experimental task and were not aware of the study purposes or hypotheses being tested. All participants were screened via questionnaire for right hand dominance. Informed consent was obtained from each participant before beginning the experiment (Appendix A). In order to be included in the study, the following additional criteria were met: 1. No medical history of nervous or musculoskeletal conditions, including arthritis, carpal tunnel syndrome, unhealed shoulder/wrist/hand injuries (breaks/sprains/neurological damage/surgeries), or any diseases of the upper extremities or peripheral circulatory systems. 49 2. No current use of any medication (stimulant or depressant) that may have caused drowsiness, fatigue, increased heart rate, or increased blood pressure. 3. No current ailments associated with undue daily fatigue. The experiment had two phases: 1) skill acquisition, which took place during sessions 1 and 2 of the study, and 2) skill retention, which took place during session 3 of the study. The design was a 3 x 2 x 10 (Group x Session x Trial) factorial for sessions 1 and 2, with repeated measures on session and trials. For session 3, which was a retention session, the design was a 3 x 10 (Group x Trial) factorial design with repeated measures on trials. In both cases levels of the first factor were the internal focus, external focus, and control groups. Levels of the session factor included acquisition session 1 and acquisition session 2. Levels of the third factor were the 10 trials per session. The dependent variables included segmental and total movement times, the number of movement units, the amount of pitch and roll during movement segment four, and the amount of cereal spillage that occurred during task completion. Data collection took place over three separate sessions, during which each participant completed the experimental task ten times, for a total of 30 trials. On the first two skill acquisition sessions, participants received, depending upon the experimental group to which they had been assigned, video instructions concerning how to perform the task. On the retention session, participants did not receive any instructions about what to pay attention to while performing the task. Task and Apparatus Task Description The experimental task was to perform an activity of daily living with a prosthesis that simulated a left arm transradial amputation. Participants used the prosthesis with the nondominant (left) upper extremity to pick up and empty a cup of cereal into a bowl, place the bowl on a plate, and move the bowl of cereal and plate across their midline to a new location (Figure 6). Figure 6. Participant seated at work station with cup, bowl, and plate arrangement. 50 51 Starting Position The participant was seated on a stool adjusted to a height that allowed for efficient completion of the task. The participant?s left shoulder was adducted to the side with the elbow flexed at 90?; the left forearm was in the power grip neutral position, with the hand grasping a wooden dowel within the distal end of the simulated prosthesis. Electromagnetic tracking sensors were placed on the skin of the lateral aspect of the participant?s humerus, and also midway down the lateral aspect of the prosthetic simulator. A piece of foam on the underside of the prosthesis rested on top of a push switch. The participant?s right forearm and hand rested on the right leg underneath the activity table. Once the participant was asked to start, the left shoulder flexed and the elbow extended, thus lifting up and moving the tip of the prosthesis 12 cm toward an aluminum cup filled with 1 cup (250 pieces) of Cheerios? cereal. The aluminum cup completed an electrical circuit which was broken when the cup was lifted off the table. The prosthesis grasped the right side of the cup of cereal, which was then moved via left shoulder horizontal adduction or trunk rotation toward an aluminum bowl, the center of which rested 20 cm to the right of the cup?s center. The cup of cereal was then poured in the bowl via left forearm supination. Once the bowl had been successfully filled with cereal, the empty cup was returned to its original position. The participant then picked up the left side of the bowl of cereal with the prosthesis and used left shoulder extension and elbow flexion to carry the bowl back (toward the trunk) and placed it on a plastic plate, the center of which was 30 cm from the bowl. The plate, which was elevated 4 cm, had a sensor on the bottom that transmitted kinematic data to a Motion Monitor version 6 (manufactured by Innovative Sports Training). Specifically, the sensor provided pitch 52 (movement about the Y axis) and roll (movement about the X axis) data during movement (Figure 7). The plate was then picked up, and moved over a 3.5 cm high barrier and across midline to a target area the center of which was 40 cm to the right of the plate. The sensor beneath the plate indicated initiation and cessation of plate motion. Analog signals from the voltage switches and electromagnetic sensors were sampled simultaneously, allowing for synchronization of kinematic and movement time data. Test Apparatus: Work Station The test apparatus work station consisted of a wooden particle board table (2 cm thick) situated 66 cm off the floor. A 142 cm wide x 81 cm deep space on the work station surface was covered with black poster board with spaces cut out for the contact switches and designated target areas (Figure 7). The far side of the table rested against a blank white wall. Participants sat on an adjustable stool 35-48 cm high. The stool had no back, which allowed for trunk flexion and extension during completion of the task. The seat of the stool was not fixed, and was free to rotate 360 degrees. The aluminum cup was 9.5 cm in diameter and 5 cm deep and held 250 Cheerios?. The aluminum bowl was 14.5 cm in diameter and 4.5 cm deep. The plastic plate was 25 cm in diameter and had a lip that was 2 cm deep (Figure 6). Test Apparatus: Simulated Prosthetic Device The prosthetic simulator (Figure 8) was designed to mimic a prosthetic device for an upper extremity transradial amputation that allows for forearm supination and pronation. Additionally, the simulator was fabricated almost completely from non-ferrous materials (primarily aluminum and fiberglass) so that the Motion Monitor was able to track and record experimental movements without signal anomalies or artifacts. The simulator had a figure-8 harness that was attached to a steel cable that ran across the Cup Switch Bowl Switch Plate Start Plate Stop Start Switch x y Figure 7. Contact switches and axes orientation. back and upper arm on which the prosthesis was worn. The control cable was the only part of the simulator that contained ferrous materials. Through pilot testing, it was determined that the cable did not limit the Motion Monitor?s ability to gather accurate kinematic data. The steel control cable inserted onto an aluminum split hook (5XA) terminal device, which has been used with regular prostheses. The prosthesis was fitted with a left handed terminal device. The device was a voluntary opening device; that is, 53 three one-pound tension rubber bands held the terminal device in the closed position, and it was opened by adjusting the tension of the cable with synchronized motions of the Figure 8. The prosthetic simulator. opposite shoulder, torso, and involved upper extremity. In order to wear the simulator, participants placed their left arm in a fiberglass sleeve and moved their hand to the distal end of the simulator where a wooden dowel was grasped (power grip) with the left shoulder adducted to the side, the elbow flexed to 90 degrees, and the forearm in the power grip neutral position. Velcro straps were then adjusted and secured. The figure-8 harness was then tightened by an assistant. Proper fit was determined by asking the participant to flex the shoulder and extend the elbow in order to open and close the 54 55 terminal device. If the participant was able to open and close the prosthesis without difficulty or discomfort, then it was determined that proper fit had been achieved. Kinematic Measurement Apparatus Data collection occurred in the Auburn University Musculoskeletal Research Laboratory (1403 Haley Center). Three-dimensional kinematic variables were assessed using the Motion Monitor version 6 (Figure 9) electromagnetic tracking system (Innovative Sports Training, Inc., Chicago, IL, USA). The electromagnetic sensors had root-mean-square position accuracy of 1.78 mm/0.5? and a resolution of 0.76 mm/0.1? within a 0.91 m operating range. Timing of the separate movement segments was measured by three electrical contact switches and one sensor that were tracked by the Motion Monitor system. Three electrical contact switches (Figure 7) were connected to the Motion Monitor to provide data about movement times for the first three segments of the task. The start position switch was a push switch that was activated by pressing down on it; that is, the circuit was completed when it was pushed down by a piece of foam attached to the underside of the prosthetic simulator. The second and third switches consisted of two sets of aluminum plates (5.5 cm x 12.1 cm) soldered to wires powered by a GW Labs GPS 1850 DC power supply, which provided 5 volts of continuous current. These switches were closed until the circuit was broken by removing the aluminum cup on the first set of plates, and the aluminum bowl on the second set. All circuits were split so that the signal traveled to both the Motion Monitor and to a four channel 100 MHz digital oscilloscope (Tektronix model number TDS 2014) that was continuously checked to ensure that all switches and circuits were functioning properly. Figure 9. The Motion Monitor version 6 electromagnetic tracking system. Procedures All participants signed an Informed Consent form (Appendix A) before testing began. They were then asked to remove all jewelry from their left upper extremity and to turn off any mobile phones or pagers, which might cause a distraction during testing. Participants were serially assigned to one of three groups: internal focus, external focus, or control, based on the order in which they were scheduled to attend the experiment. A restriction that each group contain a similar number of males and females was enforced, so that the external focus group had 5 males and 5 females, and the internal focus and control group each had 6 females and 4 males. After arriving at the lab, the participants were fitted with the simulated prosthesis and, prior to the first session, 56 57 watched a one-minute video tape that demonstrated how to use and control the prosthetic simulator. The script of the first video instructions appears in Appendix B. Participants did not watch this video before the second or third sessions. Before acquisition sessions one and two, each group watched a second video, of which there were three versions. This video contained instructions designed to induce internal, external, or no specific attentional focus, and a demonstration about how to perform the experimental task. On session three, which was a skill retention session, no video instructions were provided. The scripts for each condition were: External-focus condition: ?While completing the following task, pay attention to the cup, bowl, and plate during each part of the task. The task is as follows: lift the prosthesis off the table and grab the right side of the cup of cereal. Next, pour the cup of cereal into the bowl and then return the cup to its original place. After this, pick up the bowl and place it on the plate. Then, move the plate and bowl to the location marked with a red square. Move as quickly and accurately as possible. Remember to pay attention to the cup, bowl, and plate, and think about them during each part of the task. Later, I?m going to ask you a question about this. Begin after I say ?go?.? Internal-focus condition: ?While completing the following task, pay attention to your shoulder, elbow, and wrist as you move the prosthesis during each part of the task. The task is as follows: lift the prosthesis off the table and grab the right side of the cup of cereal. Next, pour the cup of cereal into the bowl and then return the cup to its original place. After this, pick up the bowl and place it on the plate. Then, move the plate and bowl to the location marked with a red 58 square. Move as quickly and accurately as possible. Remember to pay attention to your arm. Think about how much your shoulder, elbow, and wrist move during each part of the task. Later, I?m going to ask you a question about this. Begin after I say ?go?.? Control Condition: ?The task is as follows: lift the prosthesis off the table and grab the right side of the cup of cereal. Next, pour the cup of cereal into the bowl and then return the cup to its original place. After this, pick up the bowl and place it on the plate. Then, move the plate and bowl to the location marked with a red square. Move as quickly and accurately as possible. Begin after I say ?go?.? After playing the instructions on acquisition sessions one and two, or immediately on retention, the participants were taken to the test station and asked about how much sleep they had the night before. The answer to this question was noted. Once at the testing station, a mechanical model of the forearm segment/prosthesis interface was created by digitization of the elbow joint center and the distal end of the prosthesis. To do this, sensors were fastened to the distal lateral aspect of the participant?s left humerus and to the distal lateral aspect of the prosthetic simulator with double-sided tape and Velcro. Finally, a sensor was fastened beneath the plate with double-sided tape and Velcro. Because there was a 3.5 cm spacer beneath the plate, the sensor did not contact the testing station table. Once the participant was fitted with the device and sensors, one practice trial was performed to ensure that the task was properly understood. He or she was then told to start the first of ten trials when the investigator said ?go.? Data was collected for all ten trials, but not the practice trial. If the participant was in an internal attentional focus 59 group, reminders to pay attention to the shoulder, elbow, and wrist were given after the third and sixth trials. The script to this reminder was: ?Remember to pay attention to your arm. Think about how much your shoulder, elbow, and wrist move during each part of the task.? If the participant was in the external attentional focus group, reminders to pay attention to the cup, bowl, and plate were given after the third and sixth trials. The script to this reminder was: ?Remember to pay attention to the cup, bowl, and plate during each part of the task.? After completion of the tenth trial, participants in the internal and external focus groups were asked the following question: ?What did you pay attention to as you completed the task?? After answering this question, the participant was free to leave for that session. The study took place over three sessions ? one session per day for three days with at least one day in between, ideally Monday-Wednesday-Friday, and during the same time on each day. The time between sessions did not exceed 72 hours. During each session, participants performed the task ten times. Data Treatment and Analysis Onset algorithms for the analog circuits and plate movement were employed using custom software (LabVIEW 7, National Instruments, Austin, TX). Respective onsets were defined as the time instances when each analog signal exceeded the mean and a specified standard deviation multiple for a specified time interval. These mean and standard deviations were calculated for each signal over the initial 100 ms interval. 60 A digital analysis package was used to filter kinematic data at a frequency of 10 Hz, using a second-order low pass Butterworth filter. The filtered data was then processed with a custom-written program to yield the following kinematic variables: movement times, movement units, pitch, and roll. Movement times were measured in milliseconds; pitch and roll were measured in standard deviations of degrees. Movement units were defined via two mechanisms. The first defined the onset of a movement as the point when the velocity exceeded 50 mm/s for at least 200 ms. Then, within that movement onset, accelerations were defined as changes of 5 mm/s 2 for at least 20 ms. This definition of movement unit is consistent with that provided by Fasoli et al. (2002). Using these parameters for determining a movement unit, custom written software calculated the number of movement units for each trial analyzed. Data was collected during three experimental sessions. Acquisition data were analyzed with a 3 (Group) x 2 (Session) x 10 (Trial) ANOVA with repeated measures on the second and third factors. The Retention session analysis was a 3 x 10 (Group x Trial) ANOVA with repeated measures on the second factor. For both analyses, the individual dependent variables included segmental and total movement times, the total number of movement units during each segment of the task, the amount of pitch and roll of the plate during the final movement segment, and the amount of cereal spilled during task completion. The alpha level for the ANOVAs was set at .05. Significant group main effects were followed up with the Sidak procedure at a .05 level of significance. Significant interactions were graphed and described verbally, as recommended by Thomas, Nelson, and Silverman (2005). 61 To test for significant differences among the three groups on the amount of cereal spilled, a Chi Square analysis was performed. The Chi Square analysis was employed because of unequal variances and because of the small sample sizes. For all analyses, a p- value less than .05 was considered significant. 62 IV. RESULTS The purpose of this study was to examine the effects of externally focused (task related) versus internally focused (movement related) instructions on simulated upper extremity amputees? movement kinematics when learning a novel functional movement task. This chapter presents the results of the study and begins with a 3 (Group) x 2 (Session) x 10 (Trial) ANOVA of the skill acquisition sessions. This is followed by the results of a 3 (Group) x 10 (Trial) ANOVA of the skill retention session. This chapter will report statistically significant findings; complete ANOVA summary tables for all analyses appear in Appendix D. Chi Square analyses of the amount of cereal spilled during acquisition and retention sessions are also provided. Two reports are then presented. The first concerns the manipulation check for internal and external focus groups during the acquisition trials; the second contains debriefing comments made by participants in each group after completing the retention session. Finally, data trends across sessions are presented. While 37 participants began the study, only 30 were able to complete it satisfactorily. Six failed to attend all three sessions. A seventh participant was excluded from the study due to inconsistent performance resulting from a self-reported lack of sleep before the retention session. Therefore, data from these participants were not used. 63 No participants were excluded from the study because of failure to follow the instructions. Ten participants were in each group. Acquisition Movement Time 1 The Movement Time 1 (MT1) results for acquisition sessions 1 and 2 are presented in Tables 3 and 4. The 3 x 2 x 10 ANOVA for sessions 1 and 2 showed that the main effect for group failed to reach significance, F (2, 27) = .961, p = .395. The means (in ms) for each group were: external focus = 1949; internal focus = 2081; control = 1780. The effect size was .066 and power was .199. The session effect was significant, F (1, 27) = 6.113, p = .020, indicating that MT1 on session 2 (M = 1876 ms) was faster than session 1 (M = 1997 ms). The effect size was .185 and power was .664. The trial effect was also significant, F (9, 19) = 3.762, p = .007. This indicates that, in general, MT1 improved over the 10 trials on both days. The effect size was .641 and power was .938. However, the group x session interaction was also significant, F (2, 27) = 3.395, p = .048. The interaction appears in Figure 10, where it can be seen that the internal focus and control groups improved very little between session 1 and 2, while the external focus group gained considerably more speed between sessions relative to the other groups. The effect size was .201 and power was .589. None of the other 2-factor interactions, nor the 3-factor interaction, were significant. 64 Table 3 Movement Time 1 (M/SD) for Session 1 (Values are in milliseconds) Trial Control External Internal Grand Mean 1 1718 691 2261 871 2278 931 2085 850 2 2971 562 1943 929 2500 834 2165 800 3 1821 723 2406 1000 2070 723 2099 833 4 1762 683 2629 1338 2205 529 2199 958 5 1665 595 2227 1285 1967 682 1953 906 6 2064 1054 1838 590 2101 1057 2001 902 7 2025 894 2026 732 2034 824 2028 790 8 1676 656 2084 896 1972 373 1010 675 9 1562 414 1943 641 1973 640 1826 587 10 1664 677 1636 320 1784 403 1696 478 65 Table 4 Movement Time 1 (M/SD) for Session 2 (Values are in milliseconds) Trial Control External Internal Grand Mean 1 2366 689 2201 908 2104 457 2224 693 2 1776 766 1797 450 2084 488 1886 583 3 159 624 1954 882 2167 755 1927 755 4 1755 572 1793 588 2073 598 1874 584 5 1727 366 1692 614 2229 876 1882 678 6 1888 421 1714 639 2062 572 1888 582 7 1618 552 1581 541 2204 682 1801 682 8 1665 377 1639 561 1843 443 1715 460 9 1684 434 1782 492 2017 483 1828 475 10 1426 519 1826 821 1947 437 1733 635 MT1 Group Means for Sessions 1 and 2 1600 1700 1800 1900 2000 2100 2200 Session 1 Session 2 M ean M T 1 (m s ) Control External Internal Figure 10. Group x session interaction for MT1. Movement Time 2 The MT2 results are shown in Tables 5 and 6. The ANOVA revealed that the main effect for group was not significant, F (2, 27) = 1.837, p = .179. The means (in ms) for each group were: external focus = 6002; internal focus = 6954; control = 5937. The effect size was .120 and power was .349. The session effect reached significance, F (1, 27) = 38.625, p <.001. The effect size was .589 and power was 1.000. This finding indicates that the session 2 mean of 5816 ms was significantly faster than the session 1 mean of 6779 ms. The trial effect was significant, F (9, 19) = 9.112, p < .001. This result suggests that MT2 typically improved over the 10 trials on both days. The effect size was 66 67 .812 and power was 1.000. The session x trial interaction reached significance, F (9, 19) = 3.084, p = .019. The effect size was .594 and the power was .874. Please see Figure 11 for a plot of the session x trial data. This interaction may be significant because of the trial 6 means, where the session 1 group mean dropped 1200 ms from the trial 5 mean, while the session 2 group mean rose nearly 800 ms from the trial 5 mean. Since there were no verbal cues provided after trial 5, this result may be an anomaly. None of the other 2-factor interactions, nor the 3-factor interaction, were significant. Movement Time 3 The MT3 results are presented in Tables 7 and 8. The ANOVA showed that the main effect for group was significant, F (2, 27) = 3.541, p = .043. The means for each group were: external focus = 4088 ms; internal focus = 5299 ms; control = 4375 ms. The effect size was .208 and power was .609. A Sidak follow up test indicated that the external focus group performed the movement significantly faster than the internal focus group (p < .05), but no other pairwise differences were significant. The session effect reached significance, F (1, 27) = 14.869, p <.001. The effect size was .355 and power was .960. This finding suggests that the session 2 mean of 4084 ms was significantly faster than the session 1 mean of 5092 ms. The trial effect was significant, F (9, 19) = 5.419, p < .001. This suggests that MT3 generally improved over the 10 trials on both days. The effect size was .720 and power was .991. None of the other interactions were significant. 68 Table 5 Movement Time 2 (M/SD) for Session 1 (Values are in milliseconds) Trial Control External Internal Grand Mean 1 7780 2677 8223 2723 8346 1200 8116 2244 2 6236 2089 7952 2686 8339 3784 7509 2984 3 6997 1644 7075 3253 8237 3283 7437 2793 4 7217 2781 6028 2351 8927 4062 7390 3271 5 6925 986 6876 1521 7767 2237 7112 1674 6 5358 2048 5626 1541 6719 2011 5901 1911 7 5878 1684 6295 2920 6953 2787 6375 2478 8 5696 1122 6126 1840 5853 1632 5892 1517 9 6338 2322 5823 1831 6504 1757 6221 1939 10 4810 1876 5592 2294 7102 2626 5835 2409 69 Table 6 Movement Time 2 (M/SD) for Session 2 (Values are in milliseconds) Trial Control External Internal Grand Mean 1 5847 1015 5388 1685 6814 2501 6017 1873 2 5794 2087 6246 4199 6450 1338 6163 2731 3 5952 1507 4927 1936 6425 1591 5768 1591 4 5584 1137 5504 1344 5930 1156 5672 1188 5 5120 1972 5233 1573 7148 3179 5834 2451 6 6347 1225 6177 2638 7337 2374 6620 2155 7 5016 1233 5155 1059 6485 1462 5552 1392 8 5031 1853 5338 1720 6077 1993 5482 1848 9 5392 1731 5587 1797 5939 1372 5640 1603 10 5644 907 4870 1172 5730 1476 5415 1230 MT2 Trial Means for Sessions 1 and 2 5000 5500 6000 6500 7000 7500 8000 8500 12345678910 Trial M ean M T 2 (m s ) Session 1 Session 2 Figure 11. Session x trial interaction for MT2. Movement Time 4 The MT4 results are displayed in Tables 9 and 10. The ANOVA revealed that the main effect for group was not significant, F (2, 27) = .414, p = .665. The means (in ms) for each group were: external focus = 1430; internal focus = 1561; control = 1448. The effect size was .030 and power was .110. The session effect attained significance, F (1, 27) = 13.169, p <.001. The effect size was .328 and power was .938. This finding suggests that the session 1 mean of 1600 ms was significantly slower than session 2 mean of 1359 ms. The trial effect was significant, F (9, 19) = 3.308, p = .020. The effect size was .590 and power was .868. This finding suggests that MT4 generally improved over the 10 trials on both days. None of the other interactions were significant. 70 71 Table 7 Movement Time 3 (M/SD) for Session 1 (Values are in milliseconds) Trial Control External Internal Grand Mean 1 7780 2677 8223 2723 8346 1200 8116 2244 2 6236 2089 7952 2686 8339 3784 7509 2984 3 6997 1644 7075 3253 8237 3283 7437 2793 4 7217 2781 6028 2351 8927 4062 7390 3271 5 6925 986 6876 1521 7767 2237 7112 1674 6 5358 2048 5626 1541 6719 2011 5901 1911 7 5878 1684 6295 2920 6953 2787 6375 2478 8 5696 1122 6126 1840 5853 1632 5892 1517 9 6338 2322 5823 1831 6504 1757 6221 1939 10 4810 1876 5592 2294 7102 2626 5835 2409 72 Table 8 Movement Time 3 (M/SD) for Session 2 (Values are in milliseconds) Trial Control External Internal Grand Mean 1 4242 1469 4566 2203 5168 1768 4659 1816 2 3977 1035 3902 1041 4763 1239 4214 1141 3 4431 212 4402 2410 4201 1015 4348 1841 4 5117 1939 3206 671 4416 904 4246 1485 5 4019 844 3221 799 4053 853 3765 893 6 3562 1004 4017 1597 4360 1477 3979 1376 7 4219 1320 3216 784 4460 1172 3965 1207 8 4293 1712 3867 1001 4529 1399 4230 1350 9 3774 837 3285 638 3841 824 3633 786 10 331 824 3076 611 4995 1289 3796 1263 73 Table 9 Movement Time 4 (M/SD) for Session 1 (Values are in milliseconds) Trial Control External Internal Grand Mean 1 7780 2677 8223 2723 8346 1200 8116 2244 2 6236 2089 7952 2686 8339 3784 7509 2984 3 6997 1644 7075 3253 8237 3283 7437 2793 4 7217 2781 6028 2351 8927 4062 7390 3271 5 6925 986 6876 1521 7767 2237 7112 1674 6 5358 2048 5626 1541 6719 2011 5901 1911 7 5878 1684 6295 2920 6953 2787 6375 2478 8 5696 1122 6126 1840 5853 1632 5892 1517 9 6338 2322 5823 1831 6504 1757 6221 1939 10 4810 1876 5592 2294 7102 2626 5835 2409 74 Table 10 Movement Time 4 (M/SD) for Session 2 (Values are in milliseconds) Trial Control External Internal Grand Mean 1 1835 695 1313 305 1458 349 1536 517 2 1295 498 1808 1287 1499 340 1534 830 3 1193 418 1308 347 1380 395 1294 382 4 1216 508 1317 401 1350 384 1295 423 5 1638 630 1257 411 1296 505 1397 534 6 1384 447 1254 420 1429 526 1356 457 7 1354 476 1399 277 1171 383 1308 387 8 1228 320 1252 384 1443 592 1308 443 9 1224 379 1381 600 1163 370 1256 455 10 1243 283 1405 435 1270 422 1306 379 75 Total Movement Time The Total Movement Time (TMT) results are displayed in Tables 11 and 12. The ANOVA revealed that the main effect for group was not significant, F (2, 27) = 2.603, p = .092. The means (in ms) for each group were: external focus = 13467; internal focus = 15891; control = 13540. The effect size was .162 and power was .474. The session effect was significant, F (1, 27) = 52.075, p <.001. The effect size was .659 and power was 1.000. This indicates that the session 1 mean of 15465 ms was significantly slower than session 2 mean of 13133 ms, and suggests that participants in all groups performed the task faster during the second session. The trial effect was significant, F (9, 19) = 14.305, p < .001. This indicates that TMT generally improved over the 10 trials on both days. The effect size was .871 and power was 1.000. The session x trial interaction reached significance, F (9, 19) = 2.495, p = .045. The effect size was .542 and the power was .780. The interaction is plotted in Figure 12, where it can be seen that TMT improved more during session 1 than session 2. None of the other interactions were significant. Total Movement Units The Total Movement Unit (TMU) results for sessions 1 and 2 are shown in Tables 13 and 14. The ANOVA indicated that the main effect for group failed to reach significance, F (2, 27) = .964, p = .394. The means (in movement units) for each group were: external focus = 54.52; internal focus = 57.79; control = 44.62. The effect size was .067 and power was .2. The session effect was significant, F (1, 27) = 27.798, p <.001. The effect size was .507 and power was .999. This result implies that the session 2 mean of 46.74 was significantly lower than the session 1 mean of 57.88. The trial effect reached significance, F (9, 19) = 5.748, p = .001. This indicates that the number of 76 movement units tended to decrease over the 10 trials on both days. The effect size was .731 and power was .994. The session x trial interaction attained significance, F (9, 19) = 2.455, p = .048. The effect size was .538 and the power was .772. Figure 13 plots the interaction and shows that, like the TMT session x trial interaction, TMU decreased more during session 1 than session 2. None of the other interactions were significant. Pitch The Pitch results for acquisition are shown in Tables 15 and 16. Broadly speaking, there were no statistically significant findings for this variable in any domain. The ANOVA indicated that the main effect for group failed to reach significance, F (2, 27) = 1.866, p = .174. The means (in degrees) for each group were: external focus = 2.58; internal focus = 2.44; control = 3.14. The effect size was .121 and power was .354. The session effect was not significant, F (1, 27) = .134, p = .718. This result supports the observation that the session 2 mean of 2.76 degrees was not significantly lower than the session 1 mean of 2.69 degrees. The effect size was .005 and power was .064. The trial effect was not significant, F (9, 19) = 1.463, p = .231, indicating that pitch remained essentially stable across trials. The effect size was .409 and power was .505. None of the other interactions were significant. 77 Table 11 Total Movement Time (M/SD) for Session 1 (Values are in milliseconds) Trial Control External Internal Grand Mean 1 17733 5556 17266 3904 18778 4096 18259 4555 2 14988 3056 16606 3400 18931 4774 16841 4033 3 15045 3781 15922 4637 18325 5275 16431 4662 4 15703 5594 15138 4239 20850 7433 17230 6266 5 14055 2493 15036 3292 16347 3442 15146 3144 6 14680 4163 13528 4246 16618 5505 14942 4697 7 13174 2978 13865 3543 16922 3102 14654 3518 8 12341 2704 13413 3392 14763 2691 13505 3017 9 12921 3626 13252 3298 15815 4181 13996 3822 10 12290 2822 12502 2620 16154 4636 13649 3811 78 Table 12 Total Movement Time (M/SD) for Session 2 (Values are in milliseconds) Trial Control External Internal Grand Mean 1 14306 2237 13468 3152 15545 2841 14439 2841 2 12842 2556 13703 6128 14796 1767 13780 3913 3 13246 2040 11819 3102 14174 1838 13336 2401 4 13671 2455 11819 2229 13769 2248 13087 2411 5 12504 2431 11403 2917 14725 3842 12878 3321 6 13181 2184 13162 3518 15189 3624 13844 3214 7 12208 2106 11352 1901 14321 2504 12627 2461 8 12217 2282 12096 2550 13892 3018 12735 2675 9 12075 2516 12035 2571 12960 2609 12357 2513 10 11630 1884 11177 2416 13941 1952 12249 2369 TMT Trial Means for Sessions 1 and 2 11000 12000 13000 14000 15000 16000 17000 18000 19000 12345678910 Trial Me a n TMT ( m s ) Session 1 Session 2 Figure 12. Session x trial interaction for TMT. 79 80 Table 13 Total Movement Units (M/SD) for Session 1 Trial Control External Internal Grand Mean 1 65 26 70 29 80 43 72 33 2 47 16 65 27 76 45 62 33 3 50 18 66 27 67 27 61 27 4 52 19 61 31 80 56 64 39 5 47 19 62 36 58 28 56 28 6 47 17 46 19 63 37 52 16 7 41 15 63 41 60 30 54 32 8 40 18 57 31 52 25 50 25 9 46 25 62 47 69 45 59 40 10 38 15 43 17 61 46 47 30 81 Table 14 Total Movement Units (M/SD) for Session 2 Trial Control External Internal Grand Mean 1 49 21 52 21 55 27 52 23 2 37 13 64 42 56 23 52 30 3 44 19 49 18 47 23 47 19 4 43 20 49 20 47 22 46 20 5 42 17 46 24 49 22 45 21 6 48 23 50 24 51 26 49 24 7 42 20 49 25 45 21 42 20 8 42 26 47 21 44 20 44 22 9 35 16 44 17 42 18 41 17 10 37 14 45 23 51 30 44 23 TMU Trial Means for Sessions 1 and 2 35 40 45 50 55 60 65 70 75 12345678910 Trial Me a n Mo v e m e n t U n i t s Session 1 Session 2 Figure 13. Session x trial interaction for TMU. Roll The Roll results for acquisition are shown in Tables 17 and 18. The ANOVA revealed that the main effect for group was not significant, F (2, 27) = .221, p = .803. The means (in degrees) for each group were: external focus = 2.299; internal focus = 2.262 control = 2.403. The effect size was .016 and power was .081. The sessions effect reached significance, F (1, 27) = 5.594, p <.025. The effect size was .172 and power was .626. This finding suggests that the session 1 mean of 2.418 degrees was significantly higher than session 2 mean of 2.225 degrees, and that the amount of roll decreased for all groups across sessions. The trials effect failed to reach significance, F (9, 19) = 1.817, p = .131. The effect size was .463 and power was .615. None of the other interactions were significant. 82 83 Table 15 Pitch (M/SD) for Session 1 (Values are in degrees) Trial Control External Internal Grand Mean 1 3.80 2.19 2.67 0.98 2.93 1.08 3.13 1.55 2 3.13 1.37 2.22 0.72 2.47 0.83 2.61 1.05 3 2.96 1.90 2.85 1.24 2.19 0.85 2.67 1.39 4 3.48 3.49 2.72 1.51 2.04 0.86 2.75 2.25 5 3.12 1.87 2.44 0.92 2.16 0.58 2.58 1.27 6 4.04 3.05 2.57 1.10 2.90 1.70 3.17 2.14 7 2.59 0.99 2.04 0.79 2.06 0.74 2.23 0.86 8 2.91 1.17 2.30 1.10 2.21 0.82 2.47 1.05 9 3.28 2.03 2.60 2.10 2.41 0.99 2.30 0.75 10 2.77 1.30 2.39 1.26 2.30 0.75 2.48 1.10 84 Table 16 Pitch (M/SD) for Session 2 (Values are in degrees) Trial Control External Internal Grand Mean 1 2.27 0.97 2.90 0.84 3.07 1.58 2.74 119 2 3.14 1.94 2.87 1.03 2.48 1.23 2.83 1.43 3 4.23 4.43 2.36 1.05 2.50 1.12 3.03 2.75 4 2.19 0.98 2.37 1.05 2.70 1.02 2.42 1.01 5 3.33 3.52 2.32 0.87 2.09 1.02 2.58 2.17 6 2.20 0.98 2.52 0.71 2.69 1.05 2.47 0.92 7 3.83 3.99 3.18 1.42 2.06 0.88 3.02 2.52 8 3.68 4.83 2.59 1.23 2.46 0.76 2.91 2.86 9 3.78 4.77 3.11 2.89 2.91 1.28 3.27 3.21 10 2.15 0.93 2.54 0.88 2.24 0.78 2.31 0.85 85 Table 17 Roll (M/SD) for Session 1 (Values are in degrees) Trial Control External Internal Grand Mean 1 3.35 1.68 2.76 0.80 2.28 0.80 2.48 0.91 2 2.45 1.05 2.37 0.85 2.79 0.80 2.48 0.91 3 2.45 1.05 2.37 0.85 2.32 0.69 2.38 0.85 4 2.45 1.01 2.40 0.85 2.30 0.64 2.38 0.82 5 2.63 0.82 2.24 0.59 2.62 0.69 2.50 0.70 6 2.55 1.24 2.31 0.64 2.46 0.62 2.44 0.86 7 2.58 0.96 2.44 0.55 2.12 0.64 2.38 0.74 8 2.43 1.00 2.18 0.89 2.19 0.90 2.27 0.91 9 2.07 0.82 2.30 0.91 2.38 1.01 2.25 0.90 10 2.38 0.69 2.25 0.78 2.13 0.73 2.25 0.71 86 Table 18 Roll (M/SD) for Session 2 (Values are in degrees) Trial Control External Internal Grand Mean 1 2.69 0.78 2.69 .87 2.50 1.10 2.63 0.90 2 2.45 1.22 1.98 0.75 2.37 0.67 2.27 0.91 3 2.15 0.65 2.65 0.94 1.92 0.56 2.24 0.77 4 2.84 2.29 2.10 0.75 2.44 1.41 2.46 1.58 5 2.11 1.22 2.22 1.04 1.97 0.54 2.10 0.95 6 1.71 0.43 1.92 0.78 2.03 0.70 1.89 0.65 7 2.58 1.31 2.29 0.83 2.08 0.51 2.31 0.93 8 1.97 0.70 1.89 0.85 2.17 0.79 2.01 0.76 9 1.81 0.55 2.23 0.92 2.58 1.19 2.20 0.95 10 2.12 0.85 2.38 0.59 1.93 0.71 2.14 0.72 87 Cereal Spilled The amount of cereal spilled was summed for each group across all ten trials for sessions 1 and 2 to obtain a more global representation of motor performance. For session 1, the total number of cereal pieces spilled for each group was: external focus = 192; internal focus = 502; control = 311. A chi square analysis was performed to determine if significant differences existed among groups. The analysis produced a significant group effect, ? 2 (2, N=30) = 146.01, p < .001. The effect size was 2.43, suggesting that the observed frequencies deviate substantially from the expected frequencies. Since the expected amount of cereal spilled by each group was 335 pieces, the external focus group spilled less, while the internal focus group spilled more, cereal than expected. For session 2, the total number of cereal pieces spilled by each group was: external focus = 255; internal focus = 311; control = 330. A Chi Square analysis indicated that there was a significant difference between groups, ? 2 (2, N = 30) = 10.17, p < .01. The effect size was .168, suggesting that the observed frequencies deviate moderately from the expected frequencies. Retention Movement Time 1 The MT1 results are presented in Table 19. The ANOVA revealed that the main effect for group was not significant, F (2, 27) = 2.445, p = .106. The means for each group were: external focus = 1595; internal focus = 2062; control = 1767. The effect size was .153 and power was .449. The trial effect failed to reach significance, F (9, 19) = .571, p = .804. The effect size was .213 and power was .199. The group x trial interaction 88 also failed to reach significance, F (18, 38) = 1.047, p = .436. The effect size was .331 and power was .580. Table 19 Movement Time 1 (M/SD) for Retention (Values are in milliseconds) Trial Control External Internal Grand Mean 1 1793 802 1669 419 2198 739 1887 690 2 1681 548 1655 742 2215 963 1850 788 3 1820 669 1553 470 1979 522 1784 569 4 1811 846 1898 1210 2098 593 1936 895 5 1762 772 1452 354 2282 679 1832 699 6 1643 697 1588 426 2043 449 1758 559 7 1947 690 1571 874 1743 389 1754 675 8 1851 693 1472 535 1998 605 1774 634 9 1653 460 1351 434 2120 667 1708 605 10 1711 569 1739 1246 1941 601 1797 840 89 Movement Time 2 The MT2 results are presented in Table 20. The main effect for group was not statistically significant, F (2, 27) = .408, p = .669. The means for each group were: external focus = 5217; internal focus = 5761; control = 5612. The effect size was .029 and power was .109. The trial effect failed to reach significance, F (9, 19) = 1.436, p = .241. The effect size was .405 and power was .496. There was no significant group x trial interaction, F (18, 38) = 1.450, p = .165. The effect size was .407 and power was .763. Movement Time 3 The MT3 results are presented in Table 21. The main effect for group was not statistically significant, F (2, 27) = 2.029, p = .151. The means for each group were: external focus = 3286; internal focus = 3895; control = 3365. The effect size was .131 and power was .381. There was no significant trial effect, F (9, 19) = 1.109, p = .403. The effect size was .344 and power was .384. The group x trial interaction was not significant, F (18, 38) = .667, p = .820. The effect size was .240 and power was .364. Movement Time 4 The MT4 results are presented in Table 22. The ANOVA revealed that the main effect for group failed to reach significance, F (2, 27) = .079, p = .924. The means for each group were: external focus = 1379; internal focus = 1316; control = 1377. The effect size was .006 and power was .061. The trial effect failed to reach significance, F (9, 19) = 1.310, p = .295. The effect size was .383 and power was .454. There was no significant group x trial interaction, F (18, 38) = 1.713, p = .080. The effect size was .448 and power was .846. 90 Table 20 Movement Time 2 (M/SD) for Retention (Values are in milliseconds) Trial Control External Internal Grand Mean 1 6426 2123 5490 1344 6075 1311 5997 1627 2 5622 1475 5205 2417 7206 4352 6011 3022 3 6528 1868 5194 1440 5407 1005 5710 1547 4 5306 1052 6175 3025 5638 1190 5707 1938 5 5572 2078 4988 1421 5675 1227 5411 1590 6 5299 1949 5826 2980 5990 1629 5705 2202 7 5190 1307 4416 1133 5425 1980 5010 1529 8 5527 2165 5251 2649 5445 1071 5407 2001 9 5020 1774 5143 1589 5248 1179 5137 1483 10 5630 1627 4486 1824 5510 1212 5209 1607 91 Table 21 Movement Time 3 (M/SD) for Retention (Values are in milliseconds) Trial Control External Internal Grand Mean 1 3059 674 3213 673 3660 975 3281 807 2 3211 712 3416 1187 4268 1527 3632 1239 3 3264 791 3277 770 3550 916 3364 810 4 3467 921 3260 959 4064 1407 3597 1133 5 3851 2021 3148 1063 3457 869 3485 1392 6 3391 1093 3833 1647 3826 744 3683 1195 7 3200 745 3163 1775 4556 2573 3640 1908 8 3596 1331 3410 864 4528 2360 3845 1661 9 3491 1460 3091 896 3678 820 3420 1087 10 3118 721 3137 799 3357 779 3204 749 92 Table 22 Movement Time 4 (M/SD) for Retention (Values are in milliseconds) Trial Control External Internal Grand Mean 1 1300 334 1180 308 1017 299 1166 325 2 1317 539 1437 446 1101 300 1285 447 3 1374 713 1229 281 1393 590 1332 544 4 1063 295 1450 737 1291 409 1268 523 5 1163 252 1686 761 1881 1300 1577 905 6 1333 301 1362 200 1223 238 1306 249 7 2541 4139 1258 340 1464 557 1754 2403 8 1230 285 1236 309 1174 234 1213 269 9 1190 408 1231 508 1325 363 1249 419 10 1262 513 1716 1239 1287 613 1422 848 93 Total Movement Time The Total Movement Time results are presented in Table 23. The main effect for group was not statistically significant, F (2, 27) = .912, p = .414. The means for each group were: external focus = 11474; internal focus = 13034; control = 12122. The effect size was .063 and power was .191. The trial effect was not significant, F (9, 19) = 2.274, p = .063. The effect size was .519 and power was .733. There was no significant group x trial interaction, F (18, 38) = 1.177, p = .326. The effect size was .358 and power was .646. Total Movement Units The Total Movement Unit results are presented in Table 24. The ANOVA showed that the main effect for group failed to reach significance, F (2, 27) = .027, p = .973. The means for each group were: external focus = 43.69; internal focus = 43.39; control = 41.88. The effect size was .002 and power was .054. The trial effect was significant, F (9, 19) = 2.764, p = .030. This indicates that, in general, Total Movement Units decreased over the 10 trials. The effect size was .567 and power was .828. The group x trial interaction was not statistically significant, F (18, 38) = .947, p = .533. The effect size was .310 and power was .526. Pitch The Pitch results are presented in Table 25. The ANOVA revealed that the main effect for group was not significant, F (2, 27) = .297, p = .746. The means for each group were: external focus = 2.95; internal focus = 2.67; control = 2.91. The effect size was .022 and power was .092. There was no significant trial effect, F (9, 19) = 1.095, p = 94 .411. The effect size was .342 and power was .379. The group x trial interaction was not significant, F (18, 38) = .848, p = .637. The effect size was .287 and power was .470. Roll The Roll results are presented in Table 26. The main effect for group was not statistically significant, F (2, 27) = .512, p = .605. The means for each group were: external focus = 2.13; internal focus = 2.19; control = 2.34. The effect size was .037 and power was .125. There was no significant trial effect, F (9, 19) = 2.116, p = .081. The effect size was .501 and power was .696. The group x trial interaction failed to reach significance, F (18, 38) = 1.189, p = .317. The effect size was .360 and power was .652. Cereal Spilled The amount of cereal spilled by each group during all ten trials of retention was summed to obtain a more aggregated account of motor performance. The total number of cereal pieces spilled for each group was: external focus = 126; internal focus = 201; control = 256. A Chi Square analysis showed that there was a significant difference among groups, ? 2 (2, N=30) = 43.89, p < .001. The effect size was .732, suggesting that the observed frequencies deviate substantially from the expected frequencies. Since the expected amount of cereal dropped by each group was 194 pieces, the external focus group dropped less, while the control group dropped more, than anticipated. 95 Table 23 Total Movement Time (M/SD) for Retention (Values are in milliseconds) Trial Control External Internal Grand Mean 1 12589 2685 11462 2289 12949 1800 12333 2299 2 11831 2381 11714 2717 14791 5309 12779 3859 3 12986 3386 11254 2157 12329 2599 12190 2762 4 11648 2489 12784 4755 13092 2080 12508 3268 5 12347 2822 11247 2696 13297 2478 12297 2713 6 11666 2949 12607 4631 13083 2270 12452 3364 7 12877 5774 10408 3748 13188 3003 12158 4371 8 12204 2829 11370 3752 13145 3028 12239 3200 9 11355 2465 10815 3184 12371 2338 11514 2676 10 11721 2639 11078 3819 12095 2270 11631 2910 96 Table 24 Total Movement Units (M/SD) for Retention Trial Control External Internal Grand Mean 1 51 33 43 17 45 18 46 23 2 44 26 49 25 54 35 49 28 3 46 25 49 33 40 18 45 26 4 36 18 44 23 40 16 40 19 5 42 15 41 17 49 22 44 18 6 36 18 47 19 39 15 41 17 7 46 38 43 24 42 14 44 27 8 45 24 44 28 46 23 45 24 9 34 14 37 18 40 20 38 16 10 38 16 39 19 38 16 38 17 97 Table 25 Pitch (M/SD) for Retention (Values are in degrees) Trial Control External Internal Grand Mean 1 2.27 1.58 2.76 1.16 2.09 1.05 2.37 1.27 2 2.81 1.57 3.10 1.59 2.51 0.88 2.81 1.36 3 2.17 0.79 2.92 1.57 2.53 0.88 2.54 1.14 4 3.00 1.23 2.46 0.92 2.30 0.90 2.59 1.04 5 4.33 4.70 3.38 2.10 2.55 1.02 3.42 3.01 6 3.06 1.39 2.88 1.19 2.49 0.87 2.81 1.15 7 3.59 1.23 2.84 1.36 3.40 2.17 3.28 1.62 8 2.71 1.90 3.21 1.30 2.44 0.86 2.79 1.41 9 2.47 0.69 2.27 0.81 3.06 1.32 2.60 1.00 10 2.65 1.33 3.63 1.80 3.31 2.11 3.20 1.76 98 Table 26 Roll (M/SD) for Retention (Values are in degrees) Trial Control External Internal Grand Mean 1 2.52 1.51 2.93 1.20 2.23 1.18 2.56 1.29 2 2.11 0.74 2.12 0.55 2.49 0.72 2.24 0.67 3 2.21 0.44 1.99 0.72 2.28 1.00 2.16 0.74 4 2.50 1.11 1.91 0.84 2.14 0.55 2.18 0.87 5 2.43 0.92 2.04 0.91 2.52 1.12 2.33 0.98 6 2.72 1.46 1.98 0.84 1.96 0.89 2.22 1.12 7 2.47 0.94 1.95 0.71 2.05 0.83 2.16 0.84 8 2.36 0.99 2.01 0.99 1.96 0.55 2.12 0.86 9 2.01 0.28 1.89 0.64 1.94 0.75 1.95 0.57 10 2.07 0.65 2.43 1.04 2.31 0.96 2.27 0.88 99 Session 1 and 2 Manipulation Check Comments After completing session 1 and 2, each participant in the internal and external focus groups was asked what they paid attention to while performing the task. Without exception, participants reported attending to what they had been asked to attend to in the video instructions. For the external focus group, the reply was the cup, bowl, and plate. For the internal focus group, the reply was their shoulder, elbow, and wrist. Impact of Verbal Reminders After trials three and six of session 1 and 2, the internal and external focus groups received a reminder to pay attention to the cup, bowl, and plate, or their shoulder, elbow, and wrist, respectively. It was anticipated that these reminders may in some way impact motor performance on trials four and seven for the external and internal focus groups. A review of the data for the external focus group showed that after the reminders, performance across all variables generally improved. Conversely, the internal focus group performed markedly worse after the reminders during session 1, especially on trial four. However, this pattern of poor performance after the reminders did not recur during session 2. In Wulf and Weigelt?s (1997) ski simulator experiments, the authors collected data on specific trials, some following attentional reminders and some not, and found that, except for a high stress condition at the very end, results were independent of the trial after which reminders were provided. 100 Debriefing Comments Following the Retention Session The participants? debriefing comments regarding what they attended to while performing the retention trials were recorded immediately after the last trial ended. Since the control group had not received attentional focus instructions at any point in the experiment, it was of interest to record their approach to the task. The control group reported a variety of attentional focus strategies while completing the task. Six participants reported paying attention to the cup, bowl, and hook. Three others reported attending to where the Cheerios? were in the cup so as not to spill them. One participant reported attending to his posture and trunk, and sometimes his shoulder, while performing the task. Similar to session 1 and 2, all 10 external focus group participants stated that they paid attention to the cup, bowl and plate while completing the task. However, two external focus participants reported also paying attention to their left wrist during the pronation and supination movement that occurs during MT2. In like fashion, all 10 internal focus group participants reported attending to their shoulder, elbow, and wrist while completing the retention trials. However, two internal focus participants reported paying attention to not spilling the cheerios, while a third reported paying attention to the hook and also the direction of grasp, or where the hook was going. Group Comparisons Across Sessions The following graphs capture group trends in performance across sessions for selected variables. Each data point represents the average of all performances for each group during the session indicated. Figure 14 shows the amount of cereal spilled by each group across sessions, and displays the differences among the groups. Figure 15 shows total movement time for each group across sessions, and displays the relatively slower movement times produced by the internal focus condition. Figures 16 and 17 show the amount of plate pitch and roll respectively, and depict the relatively inferior performance of the control group. Figure 18 shows total movement units for each group across sessions, illustrating the comparatively smooth movement pattern of the control group during sessions 1 and 2, as well as the improved smoothness of the other groups? performance during retention. Amount of Cereal Spilled for Each Group Across Sessions 0 100 200 300 400 500 600 Acquisition 1 Acquisition 2 Retention A m ount S p ille d Control External Internal Figure 14. Amount of cereal spilled for each group across sessions. 101 Total Movement Time for Each Group Across Sessions 10000 11000 12000 13000 14000 15000 16000 17000 18000 Acquisition 1 Acquisition 2 Retention TM T ( m s ) Control External Internal Figure 15. Total movement time for each group across sessions. Plate Pitch for Each Group Across Sessions 2 2.2 2.4 2.6 2.8 3 3.2 3.4 Acquisition 1 Acquisition 2 Retention P i tch (d e g ) Control External Internal Figure 16. Plate pitch for each group across sessions. 102 Plate Roll for Each Group Across Sessions 2 2.1 2.2 2.3 2.4 2.5 2.6 Acquisition 1 Acquisition 2 Retention R o ll ( d e g ) Control External Internal Figure 17. Plate roll for each group across sessions. Total Movement Units for Each Group Across Sessions 35 40 45 50 55 60 65 70 Acquisition 1 Acquisition 2 Retention M o v e me n t U n it s Control External Internal Figure 18. Total movement units for each group across sessions. 103 104 V. DISCUSSION The purpose of this study was to examine the effects of externally focused (task related) versus internally focused (movement related) instructions on simulated upper extremity amputees? movement kinematics when learning a novel functional movement task. This chapter contains a discussion and interpretation of the results of this experiment. The results will be discussed in the context of the present hypotheses and other research in this area. Comments made by participants during debriefing will be included and suggestions for further research will be offered. Overall Findings The present results indicate that instructions designed to manipulate attentional focus while learning a novel task in a simulated rehabilitation setting can significantly affect motor learning and performance outcomes. The sole variable that was consistently influenced by attentional focus instructions during both the skill acquisition and retention sessions was the amount of cereal spilled. Findings indicated that the external focus group produced significantly less cereal spillage than the internal focus and control groups. Importantly, this increased accuracy was achieved with movement times that were similar to, or faster than, the other groups. Concerning the retention trial results, findings suggest that attentional focus instructions did not significantly impact motor 105 performance for the following variables: movement time, movement units, plate pitch, and plate roll. Finally, subjective comments by participants in the control group revealed that most preferred to use an external attentional focus approach while learning to perform the task. The first hypothesis predicted that during the retention session of the study, movement time would be faster for the external focus group than for the internal focus and control groups for each of the subtasks and for overall movement time. The results suggest that, while the externally focused and no instruction conditions consistently produced faster movement times than the internally focused instructions, there were no significant differences between the three conditions. Therefore, the first hypothesis was not supported. The results also showed that movement times improved across all three conditions during the acquisition sessions, suggesting that external focus instructions, internal focus instructions, as well as no explicit attentional focus instructions led to improved performance on this task during the acquisition phase. The finding that the external focus group did not perform significantly faster than the other groups in retention does not coincide with most of the literature, where the majority of the findings show significant group differences favoring external focus in retention (Singer et al., 1994; Wulf et al., 1998; Wulf et al., 2001). One possible explanation for this finding is the generally low statistical power of this study. It may be that significant differences between groups could be detected with a larger sample size. The second hypothesis predicted that during the retention session, movement organization for the task, as defined kinematically by the total number of movement units, would be most efficient for the external focus group. This hypothesis was also not 106 supported by the results of this experiment. Contrary to expectations, the control group consistently produced the fewest movement units. Although not statistically significant, this difference was most salient during the first session, where the mean number of movement units was 47.3 for the control group, 59.4 for the external group, and 66.9 for the internal group. As the experiment progressed to the retention session, the number of movement units decreased for all groups, but more markedly for the internal and external focus groups, nearly creating a point of convergence for all groups at 44 movement units. There is support for this finding in the literature. In Fasoli et al.?s (2002) functional reach study with stroke patients, the only significant results for movement units were found in the control group for two of three tasks. In that study, the authors suggested that percentage of time to peak velocity and movement units may not be a sensitive outcome variable for detecting the effects of instruction on reach with persons with stroke. This suggestion may apply as well to detecting the effects of instruction on simulated amputees learning to perform an activity of daily living. A possible explanation for why the control group initially produced fewer movement units rests with Fitts? Law (Fitts, 1954). Fitts? Law states that an inverse relationship exists between the difficulty of a movement and the speed with which it can be performed, also known as the speed-accuracy trade-off. In this experiment, although the instructions for the control group requested that participants perform the task as quickly and accurately as possible, the results suggest that the control group?s bias was toward speed rather than accuracy. During the first session, the control group had the fastest TMT of 14292 ms, while it dropped 119 more cereal pieces (or 1.5 times more) than the external focus group. If mere completion of the task was valued more than 107 accurate completion of the task, then it is feasible that less care would be taken during task performance. This emphasis on speedy completion during sessions 1 and 2, in turn, would produce a smoother, more homogenous movement, since the care and attendant movement unit velocity changes required to accurately position the prosthetic hook for picking up and pouring the cereal would be minimized. When, during retention, all groups were allowed to perform as they wished, these differences, while still not statistically significant, were less pronounced. The third hypothesis predicted that, during retention, movement stability, as defined kinematically by the amount of plate pitch and roll during transfer of the cereal, would be greatest for the external focus group. Results showed that all groups performed similarly, falling within one-third of a degree (Figures 16 and 17). Therefore, this hypothesis was not supported by the results of this experiment. Notably, during session 1, the control group displayed more pitch and roll than the external and internal focus groups. This result may also be a reflection of the speed-accuracy trade-off (Fitts, 1954). A potentially important observation that was not captured by statistical analyses concerning this segment of the task should be noted. As the plate was picked up and moved over the 3.5 cm barrier to the target area, the external focus and control groups were observed to perform the task while sitting upright, flexing and horizontally adducting the shoulder, and flexing and extending the elbow as necessary. Conversely, the internal focus group often kept the shoulder and elbow joints rigid in an attempt to perform the motion by twisting the trunk or by rotating on the chair. The movement tended to appear as a one piece motion that did not have segmental independence. This segmental joint rigidity proved to be expedient in completing the task, but appeared to be 108 a less efficient movement strategy. The ?constrained action hypothesis? (Wulf, McNevin, & Shea, 2001), suggests that when individuals adopt an internal focus, they try to consciously control their movements. This conscious control inadvertently disrupts the automatic control processes and hinders effective movement, which may account for the observations made during this segment of the task. The fourth hypothesis for this experiment was that, during retention, the amount of cereal spillage would be least for the external focus group. This hypothesis was supported by the results of this experiment. Importantly, this increased accuracy was produced with an external focus group TMT that was slightly faster than the other groups. The results suggest that external focus instructions produced a movement pattern that was as fast and smooth as the other groups, but with significantly less spilled cereal. Therefore, there is no evidence that a speed-accuracy trade-off was operating. This is an important finding, since, on a therapeutic level, less cereal spillage might produce more self-esteem and satisfaction during the process of learning how to use a prosthesis. In Lake?s (1997) simulated upper extremity prosthesis study, he found that the individuals who received prosthetic training performed activities of daily living in a skillful, efficient manner, exceeding the performances of the untrained control group in all tasks. However, significant differences were found in only two tasks. When the results of Lake?s study are considered with the present findings, it appears that modifying prosthetic training protocols so that the use of external attentional focus is emphasized may produce optimal motor learning results. Concerning the amount of cereal spilled during sessions 1 and 2, the external group spilled more cereal during the second acquisition session than the first, while the 109 internal focus group had the opposite effect. Furthermore, the control group spilled relatively similar amounts during both sessions. These results must be considered in light of decreasing TMTs for each group. In reviewing the literature, studies by Perkins- Ceccato (2003) and Black (2004) both found that, over time, novice participants receiving internal focus instructions tended to improve their performance, and that external focus participants, who at first tended to outperform their cohorts, gradually lagged in performance. The present results tend to agree with those findings. On the other hand, the control group spilled similar amounts of cereal during sessions 1 and 2 while also decreasing TMT. In terms of cereal spilled, by the second session, the control group performed the worst (Figure 14). It was observed during the experiment that, relative to the other groups, the control group seemed more concerned with finishing the task than with cereal spillage. Since this question was not specifically explored during the post-experiment interview, this observation remains speculative. Nevertheless, this interest in simply completing the task may explain the lack of improvement by the control group. The significant session x trial interaction for MT2 during session 1 was likely the result of a single trial, during which the performance on session 1 dramatically improved and the performance on session 2 decreased. Because this was a single trial, and not a general trend, it is difficult to attach much practical importance to this finding. Because the TMT and TMU results were impacted by a trial that followed a verbal attentional focus reminder (trial 4), there may be a relationship between impaired performance and the verbal cue. However, because there were also just as many, if not more, trials that did not follow verbal cues that also impacted the results, this explanation can only be partial 110 in scope. The MT1 group x session interaction showed that, while the internal focus and control groups displayed similar rates of MT1 improvement between session 1 and 2, the external focus group gained considerably more speed between sessions relative to the other groups. The external focus group improved 302 ms between sessions, while the internal focus group improved 16 ms, and the control group improved 47 ms. Since MT1 encompasses the start of the activity to picking up the cup of cereal, this result suggests that using external focus instructions to teach a complex movement pattern may improve the quality of the initial movement phase. Alternatively, this may also show that the instructions were fresh in the minds of the participants, and that they adhered to the instructions more diligently during the early phase of the task. Finally, results showed that the external focus group was significantly faster than the internal focus group, but not the control group, for MT3 during sessions 1 and 2. This phase of the task, which involved picking up the bowl of cereal with the prosthesis and placing it on a plate, required precise motor control to pick up the bowl. It was observed that the internal focus group had more difficulty picking up the bowl than the other groups. Therefore, as Wulf and Prinz (2001) suggest, it appears that external focus instructions enhanced the skill acquisition process for this part of the task. The participants? debriefing comments during retention are relevant to the interpretation of the results of this experiment. Since the control group did not receive any attentional focus instructions, it was of interest to determine what their natural attentional bias had been. Nine of the ten participants in this group elected to adopt an external focus strategy by paying attention to the cup, bowl, plate, or cereal in the cup. Only one participant chose an internal focus strategy by attending to his posture and 111 trunk, and shoulder at times, as he performed the task. The inclination to adopt an external focus of attention agrees with the findings of Wulf, Shea, & Park (2001). In Experiment 2 of that study, participants were given two practice sessions to learn how to perform a balancing task on a stabilometer. During these sessions the researchers provided internal and external focus instructions, and participants were free to switch between the approaches during practice if they desired. The authors found that on day three, which was a retention session, most participants chose an external focus strategy. Regarding the debriefing responses of the external and internal focus groups, the majority (75 %) stated that they continued to use the same attentional focus strategy they had used during both acquisition sessions. However, five participants out of 20 reported switching their attentional focus for the retention session. Of the five who switched, two were external focus and three were internal focus participants. While the two external focus participants reported adopting an internal focus strategy for only a specific part of the task (pronation and supination while pouring the cereal), the internal focus participants reported using an external focus approach for most, if not all, of the task. There is support in the literature for these apparently contradictory results. In the case of the two external focus participants who switched to an internal focus preference while pouring the cereal, the findings of Perkins-Ceccato et al. (2003) may provide an explanation. In that golf study, the authors found internal focus to be more beneficial than external focus to novices who were learning how to perform a golf pitch shot. Although the Perkins-Ceccato study did not investigate attentional focus preferences, per se, it may be that participants in the present study adopted an internal focus because they did not yet feel skilled enough to perform the pouring motion without attending to their wrist. In the 112 case of the three internal focus participants who adopted an external focus, the findings of Wulf, Shea, and Park (2001), as discussed previously, may provide an explanation. In Experiment 2, novice participants, when given a choice, were shown to prefer external attentional focus. In the current study, when participants were not explicitly directed to use internal attentional focus, three of ten reported choosing external attentional focus. A difference with the current findings is that participants were never provided external focus instructions, and so had to essentially come to this approach on their own. Based on learning the motor task used in this study, there may be some implications for occupational and physical therapists working with upper extremity amputees. First, instructions that emphasize an external attentional focus strategy may be used to improve movement accuracy when recalling how to perform the task. Importantly, this accuracy is not gained at the expense of movement speed. Second, during practice sessions, external focus instructions may improve both movement speed and accuracy. Notably, this improved movement accuracy and efficiency may foster higher acceptance rates of upper extremity prostheses. Third, the results show that internal focus instructions clearly did not result in improved movement efficiency or accuracy. Thus, when presented with the opportunity to use internal or external focus instructions, a bias toward external focus instructions should be adopted. Finally, performance results of the control group suggest that when attentional focus instructions are omitted, movement accuracy is sacrificed for movement speed, thus causing undesirable cereal spillage. Therefore, not providing instructions may lead to unwanted errors, and create frustration which, ultimately, may result in rejection of the prosthesis. This finding suggests that prosthetic training by a skilled therapist will be more beneficial 113 than reducing or omitting therapy and allowing the patient to self-train on how to use the prosthesis. Conclusions Based on the findings of this study, the following conclusions are made: 1. Movement time and movement units are not affected by instructions designed to manipulate attentional focus while learning how to perform a novel task with a simulated prosthesis. 2. The amount of pitch and roll that may occur while learning to pick up and move a plate with a simulated prosthesis is not affected by instructions designed to manipulate attentional focus. 3. The amount of cereal spillage that may occur while learning to pick up a cup of cereal, pour the cereal into a bowl, and pick up and move the bowl with a simulated prosthesis is significantly affected by instructions that promote an external attentional focus. Recommendations for Further Research The findings of this study form the basis for the following recommendations for further research: 1. Further attentional focus research should be performed with participants who have an actual clinical condition, rather than a simulated condition. Participants who have the condition being investigated may have a higher level of investment in the experimental outcome than individuals 114 simulating a condition. From a performance standpoint, in the present study, genuine amputees would have demonstrated different movement kinematics, since the length and weight of the affected limb would be less. In turn, this may have had a bearing on the experimental outcome, since they would move differently in a prosthesis. From a cognitive standpoint, since some conditions impact mental performance, attentional focus instructions may have different impacts upon motor learning in patient populations with cognitive impairments. Stroke and multiple sclerosis are two examples of conditions that are suitable for investigation. 2. Future studies should incorporate more complex activities of daily living. The increased difficulty may heighten mental and physical demands, thereby allowing subtle differences in motor performance to become more discernable. 3. The current study took place at a table with the participant seated on a seat that rotated. 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American Journal of Occupational Therapy, 48(1), 55-61. 125 APPENDICES 126 APPENDIX A INFORMED CONSENT FORM 127 128 129 APPENDIX B SCRIPT ACCOMPANYING VIDEO DEMONSTRATING HOW TO USE THE PROSTHETIC SIMULATOR 130 Thank you for agreeing to participate in this study. In this study, you will be using a transradial prosthetic simulator. In this case, it will be on your left arm. In order to use the prosthetic simulator, there are three ways to open the prosthetic hook. The first way is to move the left arm forward so that the hook opens. If you pull the arm back, the hook closes. The other way to open the hook is by moving the opposite shoulder forward. In this case, you will move the right shoulder forward. A third way of controlling the hook is by moving the left arm and right shoulder forward in combination. By moving the right shoulder back, or the left arm back, the hook closes. 131 APPENDIX C KINEMATIC DATA FOR EACH SESSION Table 27 MT 1 (ms) for Acquisition 1 Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 2015 1598 2469 2683 1662 2201 2554 3700 2743 2030 2 External 1153 1435 957 1618 815 1219 975 1120 1347 1299 3 External 2455 1264 1248 2070 2010 1619 2099 1782 1489 1139 4 External 2126 2696 2260 2667 3788 2964 2379 2321 1860 1962 5 External 3682 899 2016 1892 1159 1525 1459 1725 1592 1285 6 External 1599 1484 2709 1721 1610 1487 1654 1340 1651 1675 7 External 1256 1231 1933 1660 990 973 1075 914 1033 1471 8 External 1885 3964 2476 6103 3503 2261 2040 2613 2965 1694 9 External 3359 2479 4059 2612 2190 2228 3045 3178 2520 1929 10 External 3083 2377 3930 3268 4546 1903 2980 2144 2228 1880 11 Internal 3160 3385 3897 3099 1952 4822 2307 2412 2725 2127 12 Internal 3510 3870 2184 2476 2529 2273 1605 2728 2790 2472 13 Internal 1087 1440 1678 2142 1743 1290 1331 1644 1925 1320 14 Internal 1717 1904 1635 2003 1988 1740 1883 1880 2121 1459 15 Internal 1013 2513 1298 1047 1621 1652 1792 1911 894 1447 16 Internal 2133 2115 1803 2417 3047 2657 1579 1415 1808 1481 17 Internal 2839 2305 2070 1830 2963 2216 2393 2103 1855 2131 18 Internal 2226 3610 1778 2268 1131 1418 1361 1947 1214 2145 19 Internal 1630 1757 2521 2347 1540 1610 1940 1830 1675 1784 20 Internal 3465 2106 1841 2422 1154 1329 4149 1846 2720 1472 21 Control 1305 2289 1040 1224 1485 1362 1459 1401 1372 1329 22 Control 1142 2440 1528 1408 972 1259 1025 1124 1240 1613 23 Control 3230 2295 2767 3137 2765 3719 3107 2631 2227 2994 24 Control 1539 2071 2388 1855 2155 1276 2948 2657 1965 1467 25 Control 2181 3082 1950 1585 1603 1645 1875 1275 1353 1319 26 Control 1121 1353 978 2663 1449 3123 2204 1230 2151 887 27 Control 1192 1420 983 1062 1257 1444 1018 1489 1284 1183 28 Control 1476 1742 2431 1348 1205 1709 1116 1278 1052 1466 29 Control 2450 2580 2732 2094 2472 3819 3420 2549 1665 2764 30 Control 1540 1537 1415 1246 1289 1282 2078 1124 1315 1614 132 Table 28 MT 2 (ms) for Acquisition 1 Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 9576 8581 7182 8616 8569 8826 8459 8027 8075 7770 2 External 6338 4333 4225 3645 6217 3594 3666 3770 3953 3715 3 External 5341 5788 5518 5190 6121 4621 4739 5193 5018 4189 4 External 10421 8685 15030 9278 8050 7375 10195 8796 7259 7592 5 External 14227 13609 4192 1380 5704 4624 5524 3932 3190 3750 6 External 5883 8983 5184 5954 5524 5451 1699 7540 5494 1442 7 External 7068 6143 5261 5630 5615 4804 5143 4972 4785 5125 8 External 8367 8871 7645 7348 7595 6256 11170 6369 6340 8006 9 External 8978 9276 9505 7593 9800 4773 6755 7918 8990 8037 10 External 6035 5250 7012 5647 5563 5934 5599 4746 5126 6292 11 Internal 8174 13538 16695 4481 10757 8946 11798 9274 8736 8501 12 Internal 6492 10321 5740 12222 6026 5147 4891 5259 4997 5679 13 Internal 7711 4301 5992 4785 4397 3611 4083 4224 3647 3833 14 Internal 7854 7475 6560 6765 6107 5839 6662 6339 6095 6540 15 Internal 8134 6158 10484 11615 7312 6033 9128 6048 8271 13254 16 Internal 11298 11212 8338 7959 9652 8108 3813 3409 8788 8134 17 Internal 8504 2243 7052 17470 11274 7421 9806 5915 6056 7462 18 Internal 8305 13631 7756 7489 6451 6369 6230 5138 6211 5965 19 Internal 8610 6830 6171 10680 8610 10402 8830 7400 7395 7153 20 Internal 8377 7680 7579 5800 7086 5318 4289 5529 4840 4502 21 Control 5232 5575 6196 5238 7277 5410 5524 5151 4483 4365 22 Control 5259 4204 4667 4023 5531 4726 4304 4034 3869 4596 23 Control 8785 8165 9710 7181 7712 7640 7564 6687 8627 7442 24 Control 10429 2985 9551 13094 7964 7724 7498 6718 10998 803 25 Control 7853 6874 6937 9336 7549 8034 6384 5490 5309 4382 26 Control 9064 7389 6398 7473 6177 5483 4809 6634 5910 6203 27 Control 5293 5245 7391 6283 6778 5241 4107 5037 6657 5085 28 Control 7919 5726 6900 4541 6240 5039 5231 7110 4851 4585 29 Control 13038 10390 7183 9525 6789 6909 9050 6067 8395 7007 30 Control 4930 5806 5043 5474 4908 4378 4312 4036 4280 3636 133 Table 29 MT 3 (ms) for Acquisition 1 Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 5436 5485 6879 7174 5862 4754 4383 4367 4425 4575 2 External 3730 3748 3668 2724 3234 2700 2790 2993 2532 2385 3 External 3626 3030 3041 3489 3216 2814 2597 4961 3926 3461 4 External 6451 5736 5842 5549 4433 4876 4461 4379 4269 3613 5 External 5315 4271 3617 6443 4533 2740 3200 2344 3381 2972 6 External 5222 7102 7424 5168 4827 4819 9397 3340 5356 8991 7 External 4366 5780 3808 3802 3101 3286 3266 3519 3112 3439 8 External 5388 4823 4330 6068 4647 3733 3900 4197 4080 3595 9 External 5388 5604 5769 5042 4890 14085 4210 5009 5290 3869 10 External 4662 5444 4068 4752 3678 3706 3370 3035 4874 3128 11 Internal 6941 5959 8380 26170 5720 6910 5482 5188 5426 5824 12 Internal 5654 5060 4471 5693 4094 4381 5551 4974 3755 3452 13 Internal 3718 3244 6954 3440 3573 2865 7658 3151 2932 3126 14 Internal 7924 5479 5170 5003 4688 4690 4675 4212 4812 6189 15 Internal 4373 7385 4419 3451 3726 3763 3820 6497 4739 3797 16 Internal 12416 5631 12986 15038 7352 8748 12993 11716 7093 6014 17 Internal 7976 11276 5051 6050 4620 10086 6550 5681 4148 4530 18 Internal 8625 8268 5500 6231 5354 4831 6026 5104 14838 15425 19 Internal 4630 4100 4414 6230 4090 4948 4770 4100 4060 4507 20 Internal 8408 7385 6876 4629 5711 4088 4245 2855 3140 4069 21 Control 3391 4855 3398 3529 1721 3047 3200 3098 3009 3061 22 Control 3984 2960 3301 2818 3347 4784 2658 2421 2386 2262 23 Control 5945 5080 5664 4197 4578 5453 4490 3643 4443 3891 24 Control 8838 12812 7363 11061 6061 20354 4952 5796 5398 13192 25 Control 8914 4958 4225 6645 4729 4252 4633 4811 3928 6601 26 Control 6006 4305 3823 4274 4029 3854 3482 4397 5928 3498 27 Control 7706 3351 5701 9103 7889 5244 3193 2611 3073 2646 28 Control 5133 3920 1415 3644 2680 3525 3766 3397 3514 3664 29 Control 7366 4210 4236 4005 3898 3378 3230 3690 2610 3071 30 Control 3720 3902 5952 3538 3867 3487 3102 2939 2645 3622 134 Table 30 MT 4 (ms) for Acquisition 1 Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 1655 1394 1777 1408 4045 1585 1854 1596 1598 1346 2 External 1810 1244 2989 1020 1032 962 878 953 974 1497 3 External 1519 1546 1256 1105 1499 1655 1255 1804 1055 1054 4 External 2891 2803 1645 2621 2135 1660 1330 1595 1430 1415 5 External 1147 896 922 873 1387 915 1583 791 805 864 6 External 943 1754 914 919 953 755 916 2050 793 891 7 External 1540 1671 1355 1866 1395 1279 1284 1199 1177 1144 8 External 1897 1639 1485 1600 1517 1242 1620 1326 1850 1439 9 External 1593 1246 1972 1609 1520 1259 1450 1187 1500 1206 10 External 3234 1896 1650 1577 1422 1815 1699 1382 2440 1859 11 Internal 1496 1695 1356 1795 1749 1190 1444 1438 1101 1348 12 Internal 2022 1263 1334 1549 1587 1445 931 1259 1282 1097 13 Internal 1352 1557 2294 1294 1399 1360 1402 1341 1380 1448 14 Internal 2008 1777 1343 1167 1172 1122 1150 1399 1108 1208 15 Internal 1448 1626 1338 1238 2031 2183 2068 1016 1163 1569 16 Internal 1805 2303 2101 2378 1781 7052 2038 2192 2112 1946 17 Internal 2743 1784 1596 2250 1585 2294 2245 1791 1699 1943 18 Internal 3954 1736 1544 1428 2049 2244 1800 2091 1907 2250 19 Internal 2470 2090 1797 2375 2950 2357 3050 2550 4830 1946 20 Internal 1578 1260 1254 676 904 1426 1450 822 1860 989 21 Control 1240 1347 1646 1726 1347 1486 1583 1410 1416 1488 22 Control 1138 1035 1062 1344 1242 942 869 791 809 882 23 Control 1850 1570 1332 1154 973 1134 1261 1107 1200 1055 24 Control 6490 2628 3006 2888 1988 2257 2428 2141 1903 2271 25 Control 1716 1728 1572 1228 1478 1691 1562 1385 1351 1681 26 Control 1456 1101 1649 1739 1164 1078 1086 2104 1280 1444 27 Control 1235 3451 4102 789 879 1860 3207 1026 1117 990 28 Control 2449 1197 1046 1383 2680 1328 1648 1045 1377 1137 29 Control 2077 1150 910 1021 1394 1523 1020 879 1370 902 30 Control 1700 1148 860 1151 1025 1905 1333 997 1450 803 135 Table 31 TMT (ms) for Acquisition 1 Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 18682 17058 18307 19881 20138 17366 17250 17690 16841 15721 2 External 13031 10760 11839 9007 11298 8475 8309 8836 8806 8896 3 External 12941 11628 11063 11854 12846 10709 10690 13740 11488 9843 4 External 21889 19920 24777 20115 18406 16875 18365 17091 14818 14582 5 External 24371 19675 10747 10588 12783 9804 11766 8792 8968 8871 6 External 13647 19323 16231 13762 12914 12512 13666 14270 13294 12999 7 External 14230 14825 12357 12958 11101 10342 10768 10604 10107 11179 8 External 17537 19297 15936 21119 17262 13492 18730 14505 15235 14734 9 External 19318 18605 21305 16856 18400 22345 15460 17292 18300 15041 10 External 17014 14967 16660 15244 15209 13358 13648 11307 14668 13159 11 Internal 19771 24577 30328 35545 20178 21868 21031 18312 17988 17800 12 Internal 17678 20514 13729 21940 14236 13246 12978 14220 12824 12700 13 Internal 13868 10542 16918 11661 11112 9126 14474 10360 9884 9727 14 Internal 19503 16635 14708 14938 13955 13391 14370 13830 14136 15396 15 Internal 14968 17682 17539 17351 14690 13631 16808 15472 15067 20067 16 Internal 27652 21261 25228 27792 21832 26565 20423 18732 19801 17575 17 Internal 22062 17608 15769 26700 20442 22017 20994 15490 13758 16066 18 Internal 23110 27245 16578 17416 14985 14862 15417 14280 24170 25785 19 Internal 17340 14815 14903 21632 17190 19317 18590 15880 17960 15390 20 Internal 21828 18431 17550 13527 14855 12161 14133 11052 12560 11032 21 Control 11168 14066 12280 11717 11830 11305 11766 11060 10280 10243 22 Control 11523 10639 10558 9593 11092 11711 8856 8370 8304 9353 23 Control 19810 17110 19473 15669 16028 17946 16422 14068 16497 15382 24 Control 27296 20496 22308 28898 18168 24611 17826 17312 20264 17733 25 Control 20664 16642 14684 18794 15359 15622 14454 12961 11941 13983 26 Control 17647 14148 12848 16149 12819 13538 11581 14365 15269 12032 27 Control 15426 13467 18177 17237 16803 13789 11525 10163 12131 9904 28 Control 16977 12585 11792 10916 12805 11601 11761 12830 10794 10852 29 Control 24931 18330 15061 16645 14553 15629 16720 13185 14040 13744 30 Control 11890 12393 13270 11409 11089 11052 10825 9096 9690 9675 136 Table 32 TMU for Acquisition 1 Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 94 82 98 95 75 82 79 65 76 56 2 External 29 27 27 20 23 15 15 16 19 17 3 External 34 23 24 26 27 22 22 32 20 18 4 External 52 48 70 45 41 46 45 40 26 32 5External120714933553620412932 6 External 56 87 79 73 58 52 64 121 64 42 7 External 65 58 57 60 45 43 52 49 43 48 8 External 76 110 68 116 80 56 144 61 144 63 9 External 92 66 102 70 151 54 110 95 145 61 10 External 86 78 85 70 68 59 75 49 51 57 1Internal555386100515749554340 12 Internal 46 52 32 47 33 30 31 33 31 27 13 Internal 30 20 41 28 25 20 36 25 22 20 14 Internal 53 46 34 40 33 36 37 33 37 40 15 Internal 29 44 39 36 27 26 31 34 34 43 16 Internal 139 98 135 74 93 114 60 46 98 72 17 Internal 112 70 71 216 96 133 111 72 63 81 18Internal138171019583847190158179 19 Internal 113 124 70 108 79 79 110 96 122 68 20 Internal 90 80 64 57 61 55 69 41 84 41 21Control24281921262120181822 2Control24232724272520181720 23Control87475648434234313840 24Control63335359424649414027 25Control49403245303428232430 26Control76605475516852676648 27Control60526975775150525240 28Control82586158755954574848 29 Control 103 75 67 66 62 71 66 60 99 69 30Control82506353374940345541 137 Table 33 Pitch for Acquisition 1 Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 1.87 1.26 1.39 0.60 4.24 1.03 1.61 0.83 1.22 1.43 2 External 2.85 1.22 4.68 2.59 1.36 2.14 2.56 1.52 0.75 3.93 3 External 3.91 1.79 2.63 1.66 2.24 2.72 1.40 3.01 1.17 1.56 4 External 1.85 1.73 1.14 6.24 2.78 3.01 2.16 1.99 1.47 2.34 5 External 2.20 3.45 1.88 2.01 3.36 2.66 2.95 1.96 2.31 1.89 6 External 2.49 2.76 4.47 3.19 1.99 0.95 0.50 0.77 2.53 1.66 7 External 2.79 2.21 2.20 1.84 1.51 2.30 1.76 2.46 2.51 1.66 8 External 4.80 2.89 3.35 2.55 2.73 2.58 3.16 4.20 3.98 5.13 9 External 1.94 2.45 3.97 2.87 1.44 3.82 1.83 3.07 2.07 1.34 10 External 1.99 2.49 2.80 3.63 2.76 4.53 2.47 3.20 7.95 2.94 11 Internal 2.87 1.75 2.94 2.97 2.74 1.44 1.81 1.58 1.45 1.64 12 Internal 4.77 2.25 1.42 3.30 1.06 2.81 1.50 1.65 4.09 2.05 13 Internal 3.04 2.23 3.19 1.89 2.07 3.71 1.74 2.75 1.08 1.99 14 Internal 1.76 1.92 0.89 0.94 1.22 0.98 0.83 1.05 0.95 1.37 15 Internal 2.35 2.83 2.71 2.37 2.51 2.47 2.77 2.36 2.80 1.56 16 Internal 1.90 3.08 1.63 1.00 2.43 3.43 2.42 2.67 2.81 2.48 17 Internal 3.93 3.85 3.36 3.11 2.49 2.98 2.41 2.88 3.22 3.26 18 Internal 4.27 1.69 1.87 1.65 2.00 6.79 2.62 3.30 2.45 2.88 19 Internal 1.68 3.58 2.49 1.45 2.58 3.43 3.19 2.82 2.84 2.13 20 Internal 2.73 1.48 1.44 1.77 2.53 1.01 1.27 1.03 2.35 3.61 21 Control 3.66 3.16 4.62 1.59 3.57 4.40 2.95 5.31 3.45 6.00 22 Control 1.71 3.42 3.25 4.15 7.13 1.86 2.89 1.99 6.11 2.43 23 Control 1.81 1.29 1.56 2.21 1.26 1.11 1.27 2.67 0.87 1.77 24 Control 6.36 3.12 3.74 13.07 2.31 6.71 3.82 3.16 3.08 2.21 25 Control 1.45 2.35 1.68 1.15 1.08 1.11 1.80 1.79 2.61 3.38 26 Control 2.12 1.53 1.43 2.27 1.23 1.96 1.99 2.72 1.86 1.23 27 Control 5.80 6.23 7.42 2.59 4.06 6.84 4.48 2.98 7.46 2.42 28 Control 2.35 2.98 1.63 3.73 2.74 3.21 2.39 4.41 3.15 3.08 29 Control 5.82 3.32 2.41 1.87 3.22 2.83 2.59 1.53 1.64 2.17 30 Control 6.92 3.90 1.85 2.21 4.64 10.37 1.75 2.61 2.58 2.99 138 Table 34 Roll for Acquisition 1 Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 2.00 2.45 1.61 2.34 1.68 2.67 1.95 1.87 1.83 2.56 2 External 2.62 2.49 1.68 2.23 2.48 2.75 2.01 2.61 2.49 2.53 3 External 2.33 2.03 1.81 2.64 2.20 2.80 2.45 4.16 1.95 1.75 4 External 2.70 2.92 3.03 3.61 2.52 2.65 2.52 2.69 2.50 3.06 5 External 1.72 1.33 2.97 1.92 1.34 2.13 2.45 2.68 1.42 2.01 6 External 4.76 4.05 1.46 0.78 2.97 1.48 1.68 1.29 1.69 1.24 7 External 2.21 2.25 3.21 2.62 2.55 2.14 3.45 1.88 2.04 1.40 8 External 3.46 2.77 3.88 3.47 2.59 3.39 3.19 1.17 3.88 3.81 9 External 3.56 2.39 1.61 2.83 2.77 1.72 2.53 1.91 1.37 2.22 10 External 2.21 1.25 2.44 1.59 1.33 1.43 2.19 1.55 3.85 1.94 11 Internal 2.50 2.63 2.38 2.94 2.85 3.01 2.23 3.01 2.61 2.06 12 Internal 2.01 1.95 2.93 2.64 2.28 2.74 3.07 2.41 3.50 2.64 13 Internal 3.20 3.46 2.94 3.19 2.42 1.97 2.55 2.84 2.00 1.87 14 Internal 1.87 1.43 1.50 1.57 2.67 2.91 2.41 1.38 2.15 1.62 15 Internal 2.28 2.25 2.67 2.02 3.13 1.88 1.51 3.67 3.34 3.25 16 Internal 2.83 3.83 3.19 2.91 3.97 2.79 2.83 2.85 3.15 2.51 17 Internal 2.74 2.06 2.80 2.21 2.99 2.00 1.84 1.70 3.53 3.18 18 Internal 1.62 1.61 1.56 1.23 1.69 3.28 1.29 1.33 1.41 1.24 19 Internal 2.06 1.87 1.85 2.38 1.63 1.34 1.21 0.82 0.57 1.28 20 Internal 3.23 1.71 1.33 1.88 2.61 2.68 2.31 1.92 1.55 1.70 21 Control 5.80 3.96 3.39 3.18 2.84 2.26 2.45 2.63 1.97 3.15 22 Control 1.67 2.13 0.87 1.32 2.41 1.24 2.26 2.43 2.21 2.39 23 Control 1.45 2.41 2.97 2.11 2.91 2.14 1.77 1.51 2.07 1.55 24 Control 3.17 1.93 2.30 2.00 2.62 1.94 2.40 1.78 1.38 1.98 25 Control 3.32 4.08 4.10 4.03 3.40 2.94 4.12 3.17 2.67 3.21 26 Control 1.95 1.40 1.57 1.54 1.61 1.56 1.79 1.45 2.19 1.16 27 Control 5.89 3.72 3.66 1.37 3.25 2.59 2.07 2.88 3.11 2.01 28 Control 1.67 1.06 1.53 1.88 1.62 1.47 1.59 1.27 0.96 2.69 29 Control 4.26 3.28 2.33 3.56 1.66 4.73 2.99 2.59 0.88 2.98 30 Control 4.36 3.61 1.74 3.47 3.98 4.67 4.36 4.58 3.29 2.64 139 Table 35 Cereal Spilled for Acquisition 1 Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 2 2 1 1 2 2 0 1 4 2 2 External 13 3 2 3 2 1 5 35 3 0 3 External 0 1 0 4 1 0 1 1 2 1 4 External 11 5 32 0 0 0 0 1 0 0 5 External 0 0 1 1 1 0 0 0 1 0 6 External 7 4 3 6 0 0 1 0 0 0 7 External 1 0 0 0 0 2 2 2 0 0 8 External 0 0 1 0 1 0 0 0 0 0 9 External 0 0 1 0 1 2 0 0 1 0 10 External 1 1 1 1 0 1 4 0 0 0 11 Internal 13 2 0 3 0 0 0 0 1 0 12 Internal 7 2 0 3 3 1 0 1 1 3 13 Internal 11 6 4 28 7 2 107 2 0 2 14 Internal 3 2 0 1 0 1 1 1 1 4 15 Internal 41 3 5 16 56 28 16 3 2 3 16 Internal 0 1 0 0 0 1 0 1 0 0 17 Internal 0 0 0 5 1 0 0 0 0 1 18 Internal 0 1 0 1 2 0 0 0 0 1 19 Internal 1 0 1 1 0 1 0 1 0 0 20 Internal 3 7 20 3 11 1 6 4 2 29 21 Control 1 0 4 4 1 1 2 0 0 0 22 Control 9 5 9 4 10 67 7 11 14 26 23 Control 3 0 0 0 0 0 1 0 0 0 24 Control 0 2 0 0 0 0 0 0 0 0 25 Control 0 0 0 10 5 0 0 1 0 1 26 Control 0 0 0 1 0 1 1 0 2 11 27 Control 6 1 2 20 15 2 1 0 0 0 28 Control 1 1 0 0 0 1 0 0 0 1 29 Control 1 2 2 1 2 1 1 0 6 5 30 Control 1 2 2 2 1 3 1 4 9 0 140 Table 36 MT 1 (ms) for Acquisition 2 Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 1987 1720 3967 2032 1970 2130 1985 1695 1979 2010 2 External 1266 1052 1322 1414 1430 955 1380 896 1792 1567 3 External 2133 2016 1378 1440 1137 1240 1514 1667 1440 1452 4 External 4208 2434 2047 1316 2216 2206 1783 1587 1766 3865 5 External 1548 1585 1370 1710 757 940 930 1150 1232 1290 6 External 1824 1513 1784 1310 1390 1374 1000 1422 1416 1125 7 External 1392 1275 965 1415 1266 1251 1034 1232 1117 1138 8 External 2101 1950 1884 1905 1648 2374 1548 2092 2504 2174 9 External 2236 2075 2883 3217 2675 2739 2657 2906 2523 2200 10 External 3312 2355 1944 2168 2433 1931 1983 1741 2051 1437 11 Internal 2538 2653 2430 2419 2731 3089 3647 2561 2952 2870 12 Internal 2382 2844 2574 1423 1594 2602 2927 1617 1940 2110 13 Internal 1497 1515 1707 1268 4318 1128 1177 1073 1241 1387 14 Internal 1874 2483 1513 2405 2352 1778 1353 1467 1659 2011 15 Internal 2433 1545 2184 1298 1202 2169 2650 1772 2022 1774 16 Internal 2622 2029 2033 3085 1980 1065 2752 2238 1948 1816 17 Internal 2522 2411 3959 2242 2584 2565 2271 2351 2292 2344 18 Internal 1920 1780 1507 2099 1537 1779 1716 1906 2537 1992 19 Internal 1352 2008 1944 1928 2148 1874 2070 1811 1659 1420 20 Internal 1900 1570 1821 2565 1840 2573 1479 1632 1920 1742 21 Control 2967 1371 1263 1440 1568 1565 1432 1318 1780 1018 22 Control 2397 1036 1079 1032 1554 1874 867 961 821 1025 23 Control 3521 3634 3066 2761 2219 1943 2219 2102 2473 2554 24 Control 2877 1728 1706 2013 1948 2620 1837 1930 1908 1641 25 Control 2031 1619 1657 1745 1823 1827 1329 1637 1374 1162 26 Control 1760 1382 1303 1411 1512 1425 2778 1708 1710 1162 27 Control 1451 1105 1118 1114 1145 1470 1222 1900 1947 1070 28 Control 2565 2165 1350 2471 1742 1619 1636 1273 1384 1262 29 Control 2660 2257 2376 2096 2334 2582 1227 2102 1792 2102 30 Control 1431 1461 1675 1467 1421 1958 1637 1715 1653 1260 141 Table 37 MT 2 (ms) for Acquisition 2 Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 6363 7700 6244 6070 6680 6550 5457 5799 5474 4774 2 External 4360 1495 3785 5103 3639 4505 3606 1891 4492 3453 3 External 5599 4542 1167 4051 3150 4022 4038 4312 3804 3722 4 External 8943 6070 6188 7492 8318 9377 6793 7780 9565 6638 5 External 4731 3050 3200 3760 3939 5110 4750 4960 4164 3627 6 External 5449 6011 5358 5305 6010 5770 6550 5290 5529 6370 7 External 4205 4741 4552 4800 4539 4681 4181 4509 4396 4805 8 External 2520 17100 8297 7779 5969 8822 5934 7341 7660 4110 9 External 6286 6341 5484 6009 5490 10598 5171 6827 6112 6082 10 External 5429 5415 4991 4669 4597 2338 5068 4674 4677 5117 11 Internal 6837 7946 6909 7380 8768 8317 8479 8212 7957 7172 12 Internal 6702 5453 5793 5289 5453 11673 3385 7347 5459 3142 13 Internal 2133 3920 5369 4347 4521 3764 5661 3630 3684 5441 14 Internal 6709 5788 5651 5273 5360 6166 7117 6485 6514 6327 15 Internal 5737 6813 5292 5164 6014 6292 5125 4471 5541 6338 16 Internal 9564 8511 6579 7995 7902 10415 7699 8236 7822 7764 17 Internal 11461 6773 6257 6693 6844 6725 7331 8038 6259 6422 18 Internal 6436 6236 6908 5282 15298 5446 6618 5990 6564 5537 19 Internal 7575 7396 7966 6541 6791 6210 7165 5778 5259 5740 20 Internal 4991 5660 7530 5334 4530 8360 6275 2580 4335 3416 21 Control 5005 5418 4949 4503 6320 6122 4068 4267 5412 4769 22 Control 4974 4537 3851 4733 1686 5293 4573 1521 4186 6063 23 Control 7378 5920 6259 6054 5910 7472 5813 6792 5724 6605 24 Control 5428 7160 7483 7202 6876 7929 6058 6808 6493 6145 25 Control 6271 5541 5241 6769 5564 5329 5691 4563 5704 5406 26 Control 5717 9954 6195 5765 6950 7607 6350 3399 7597 7205 27 Control 5976 4989 4215 4287 1670 6080 2573 4895 1920 4130 28 Control 6868 6741 5393 4651 5435 7531 5806 6499 5028 4946 29 Control 6780 5968 7436 7090 6484 5811 5544 7452 7727 5631 30 Control 4073 1714 8497 4784 4305 4297 3687 4118 4130 5540 142 Table 38 MT 3 (ms) for Acquisition 2 Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 5233 3700 5820 3754 4720 3600 4110 4702 3400 4129 2 External 2945 5252 2710 2990 2602 2634 2385 4942 2861 3024 3 External 3711 2772 10575 3111 3470 6571 3202 3143 3623 2544 4 External 4329 4149 5067 4398 3945 4493 3371 3940 4122 3481 5 External 2183 2150 2550 1730 1728 1490 1520 1810 2101 1836 6 External 4405 3504 3662 3325 3200 3765 4000 3779 3408 3090 7 External 3294 3257 2857 3095 2919 2707 3373 3300 3062 3089 8 External 10171 5400 4099 3396 3128 4284 3793 3637 3263 3316 9 External 5417 4678 3072 3011 3560 4184 3494 4156 4243 3441 10 External 3968 4160 3612 3246 2941 6439 2915 5258 2765 2810 11 Internal 4979 4503 4299 4341 4294 4115 4582 3651 4393 6067 12 Internal 3939 3461 3614 4265 4141 3137 6568 3726 2896 7598 13 Internal 9051 7505 2667 2861 2917 2715 3266 2735 2607 3263 14 Internal 4342 5132 4551 5236 4754 3847 3711 3973 4417 4661 15 Internal 5967 5056 4716 4800 3986 4374 3952 3987 3542 3645 16 Internal 6824 5127 6127 5101 4805 5330 6396 5687 5275 4655 17 Internal 4188 4146 3979 3907 3055 4917 3883 6288 3572 3939 18 Internal 4804 5352 4485 5394 5377 4003 4839 4536 4096 4867 19 Internal 4925 4410 4783 5186 4295 3264 4073 3541 3184 5770 20 Internal 2661 2940 2787 3068 2905 7899 3330 7170 4432 5483 21 Control 3893 5706 3591 6788 3351 2900 3393 2906 2760 2790 22 Control 3073 2740 3961 2773 4620 2900 2972 5020 3135 2339 23 Control 4750 4185 4130 4085 4285 4611 4304 4371 4049 4012 24 Control 6493 4547 4858 5758 5583 4449 5793 4543 3919 4765 25 Control 7037 3980 4057 6996 3908 4909 3202 5541 3890 4196 26 Control 3878 3528 3153 3925 4038 3754 5001 8209 5549 3866 27 Control 2392 2949 9936 4121 4515 1800 6826 3280 4152 2540 28 Control 3866 3153 4346 8803 3901 4119 4237 3833 3218 2880 29 Control 3370 3422 3391 2990 2393 2542 2702 2418 4257 3073 30 Control 3669 5562 2990 4929 3600 3633 3758 2807 2814 2710 143 Table 39 MT 4 (ms) for Acquisition 2 Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 1765 2600 1674 1799 1880 1800 1770 1845 1456 1505 2 External 1347 1247 1302 1297 1283 1392 1290 1212 1352 1141 3 External 1352 1352 1082 592 638 735 1296 599 758 1109 4 External 1687 1648 2135 1483 1663 1543 1743 1731 1545 2087 5 External 840 950 1120 1020 676 1110 1680 950 780 807 6 External 1266 1053 1132 1850 1290 580 1080 1159 1179 1450 7 External 943 1024 1058 995 1042 1377 1000 951 2902 1411 8 External 1083 5200 1074 1531 1620 1680 1525 1427 1243 1198 9 External 1270 1260 1139 1042 1060 822 1165 1113 1114 1161 10 External 1578 1750 1369 1565 1414 1499 1442 1532 1478 2183 11 Internal 1367 1665 1448 1544 1844 2042 1904 2084 1279 1383 12 Internal 1591 1394 1438 864 857 1399 752 1491 1146 2006 13 Internal 1596 1068 1365 1327 1239 1025 947 1041 820 973 14 Internal 1118 1533 681 1349 746 1704 1202 798 814 926 15 Internal 1262 1057 1003 1102 1032 1088 1039 1147 1167 1014 16 Internal 2088 1998 1873 1712 2407 2547 1689 1832 2058 1658 17 Internal 1346 1336 1594 1118 1313 1106 797 1152 1248 1105 18 Internal 1309 1923 1097 818 1350 1111 1175 2549 1083 1088 19 Internal 1935 1796 2005 1675 1310 1392 1352 1656 1244 1805 20 Internal 969 1220 1300 1995 859 881 854 684 768 741 21 Control 2033 1935 1441 1448 2364 1701 2456 1668 1597 1469 22 Control 1656 895 1752 1018 1008 907 945 965 823 1494 23 Control 1753 1669 1504 1496 1300 1283 1096 1260 1336 1367 24 Control 2150 2200 1842 1933 2095 1914 1660 1716 2033 1110 25 Control 1939 628 584 36 1993 1741 1433 1324 1351 1132 26 Control 2138 1289 1086 1626 1754 2104 1547 1375 1039 1250 27 Control 1226 1007 957 1314 1035 940 879 800 807 875 28 Control 1200 899 999 1149 1372 1056 1234 1278 996 739 29 Control 880 1279 809 968 799 916 893 799 1004 1353 30 Control 3380 1150 959 1170 2664 1276 1402 1099 1254 1640 144 Table 40 TMT (ms) for Acquisition 2 Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 15348 15200 17705 13655 15250 14080 13322 14041 12309 12418 2 External 9918 9046 9119 10804 8954 9486 8661 8941 10497 9185 3 External 12795 10682 14202 9194 8395 12568 10050 9721 9625 8827 4 External 19167 14301 15437 14689 16142 17619 13690 15038 16998 16071 5 External 9302 7735 8210 8220 7100 8650 8880 8870 8277 7560 6 External 12944 12081 11936 11790 11890 11489 12630 11650 11532 12035 7 External 9834 10297 9432 10305 9766 10016 9588 9992 11477 10443 8 External 15875 29650 15354 14611 12365 17160 12800 14497 14670 10798 9 External 15209 14354 12578 13279 12785 18343 12487 15002 13992 12884 10 External 14287 13680 11916 11648 11385 12207 11408 13205 10971 11547 11 Internal 15721 16767 15086 15684 17637 17563 18612 16508 16581 17492 12 Internal 14614 13152 13419 11841 12045 18811 13632 14181 11441 14856 13 Internal 14277 14008 11108 9803 12995 8632 11051 8479 8352 11064 14 Internal 14043 14936 12396 14263 13212 13495 13383 12723 13404 13925 15 Internal 15399 14471 13195 12364 12234 13923 12766 11377 12272 12771 16 Internal 21098 17665 16612 17893 17094 19357 18536 17993 17103 15893 17 Internal 19517 14666 15789 13960 13796 15313 14282 17829 13371 13810 18 Internal 14469 15291 13997 13593 23562 12339 14348 14981 14280 13484 19 Internal 15787 15610 16698 15330 14544 12740 14660 12786 11346 14735 20 Internal 10521 11390 13438 12962 10134 19713 11938 12066 11455 11382 21 Control 13898 14430 11244 14179 13603 12288 11349 10159 11549 10046 22 Control 12100 9208 10643 9556 8868 10974 9357 8467 8965 10921 23 Control 17402 15408 14959 14396 13714 15309 13432 14525 13582 14538 24 Control 16948 15635 15889 16906 16502 16912 15348 14997 14353 13661 25 Control 17278 11768 11539 15546 13288 13806 11655 13065 12319 11896 26 Control 13493 16153 11737 12727 14254 14890 15676 14691 15895 13483 27 Control 11045 10050 16226 10836 8365 10290 11500 10875 8826 8615 28 Control 14499 12958 12088 17074 12450 14325 12913 12883 10626 9827 29 Control 13843 12926 14012 13144 12010 11851 10366 12771 14780 12159 30 Control 12553 9887 14121 12350 11990 11164 10484 9739 9851 11150 145 Table 41 TMU for Acquisition 2 Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1External74118662656467625751 2 External 23 13 20 25 16 21 19 14 22 17 3 External 29 24 34 21 15 23 23 21 22 15 4 External 44 34 38 34 35 29 30 31 32 43 5 External 43 52 44 43 24 41 46 35 26 24 6 External 59 51 54 85 90 47 104 53 46 93 7 External 47 43 41 43 45 49 36 47 46 47 8External421346165489252646655 9 External 69 61 55 63 63 85 62 73 66 54 10External921205453594651725753 11 Internal 39 38 30 34 40 43 39 39 38 42 12 Internal 26 31 24 24 23 27 19 29 20 16 13 Internal 31 33 22 21 26 18 28 14 16 26 14 Internal 36 41 32 38 38 36 28 28 34 33 15 Internal 37 32 29 26 27 28 29 26 33 27 16 Internal 93 79 74 73 69 62 76 79 59 61 17Internal101778355698167494966 18 Internal 64 71 54 63 84 52 60 56 76 62 19 Internal 78 68 72 82 67 58 72 64 53 120 20 Internal 42 92 55 56 44 103 37 52 44 56 21Control27332428272723192317 2Control31202421202518151827 23Control46393727323429312932 24Control34293335364236383528 25Control30202632262825222522 26Control67624757636277467246 27Control403376437298631072658 28Control67495189516661514242 29Control92456749465041424745 30Control57366046454648453857 146 Table 42 Pitch (deg) for Acquisition 2 Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 3.71 3.92 1.86 1.90 1.98 2.73 2.57 2.00 2.06 3.20 2 External 3.66 2.64 3.69 2.67 1.69 3.68 4.05 2.46 2.75 3.99 3 External 1.78 2.58 0.87 3.03 2.64 2.13 2.33 1.16 1.50 2.63 4 External 2.06 4.42 2.01 2.62 3.37 2.65 2.10 4.03 2.50 2.42 5 External 3.90 1.29 0.64 1.19 1.72 1.29 0.60 2.13 1.61 2.09 6 External 2.52 2.17 2.98 0.57 1.01 1.84 3.89 2.98 1.52 0.96 7 External 2.76 3.66 2.84 2.93 3.52 3.20 3.77 1.07 11.04 2.43 8 External 2.13 1.79 3.25 4.27 2.59 3.19 4.88 5.00 2.91 3.06 9 External 3.99 3.85 3.36 1.73 3.21 2.20 5.22 1.98 1.39 1.51 10 External 2.46 2.37 2.11 2.78 1.43 2.30 2.44 3.13 3.79 3.16 11 Internal 3.37 1.99 3.31 3.48 1.61 4.04 3.26 3.02 2.41 2.94 12 Internal 6.49 4.93 3.12 3.98 2.78 3.51 3.77 3.86 5.74 3.47 13 Internal 3.61 3.99 2.84 2.54 1.98 1.47 2.05 2.01 1.67 1.60 14 Internal 0.67 1.66 0.39 1.68 1.12 2.62 1.67 2.90 2.10 1.63 15 Internal 3.79 0.73 1.07 0.74 1.31 1.49 1.50 2.01 2.16 1.18 16 Internal 1.58 2.36 2.97 3.77 3.16 4.25 2.68 2.07 3.61 2.79 17 Internal 2.55 2.82 3.09 2.27 4.28 2.25 1.37 3.27 2.30 2.43 18 Internal 1.91 2.32 2.21 3.41 1.56 1.45 1.46 2.06 1.69 2.95 19 Internal 3.30 1.44 1.92 2.14 1.99 2.52 1.73 2.04 3.46 1.98 20 Internal 3.41 2.61 4.12 3.02 1.13 3.33 1.15 1.39 3.94 1.45 21 Control 2.44 2.87 13.97 2.72 3.11 4.03 4.50 4.80 3.50 3.02 22 Control 1.35 1.39 1.10 1.43 3.29 1.77 1.62 1.84 1.56 2.36 23 Control 2.72 2.41 3.24 3.36 2.78 2.65 2.93 1.69 2.26 2.74 24 Control 3.08 7.56 10.78 2.17 1.86 2.55 3.10 16.97 17.08 2.96 25 Control 2.23 0.72 0.71 0.44 1.12 1.17 2.21 1.42 1.04 1.55 26 Control 2.33 2.18 2.05 3.31 3.61 2.67 1.27 1.25 2.57 1.70 27 Control 1.71 3.21 2.67 1.38 0.78 0.90 2.81 0.49 2.91 0.85 28 Control 1.32 2.70 2.38 2.12 2.84 3.20 3.27 3.65 3.94 3.60 29 Control 1.15 3.32 2.25 1.65 0.99 1.40 1.72 2.61 1.74 1.84 30 Control 4.35 5.06 3.13 3.28 12.90 1.69 14.85 2.13 1.24 0.88 147 Table 43 Roll (deg) for Acquisition 2 Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 3.59 2.75 1.95 2.38 2.26 1.66 2.01 2.37 2.38 2.17 2 External 2.76 2.57 2.82 2.86 2.79 2.46 2.75 2.69 2.20 2.47 3 External 1.42 2.83 2.93 1.98 2.09 1.96 2.81 0.77 1.66 2.37 4 External 2.46 2.47 3.51 2.97 3.16 2.86 2.43 1.75 2.26 2.72 5 External 2.90 0.92 1.51 0.92 1.29 1.42 1.77 1.09 1.39 2.13 6 External 3.54 1.31 3.54 1.08 0.92 0.60 1.13 2.06 2.90 1.02 7 External 3.97 1.40 3.38 2.71 1.18 2.32 1.24 1.48 3.44 2.39 8 External 2.79 1.14 2.72 2.36 4.28 2.79 3.26 3.46 3.72 2.51 9 External 2.01 2.69 3.38 1.30 2.64 2.28 1.88 2.25 1.05 3.35 10 External 1.45 1.70 0.81 2.42 1.60 0.82 3.63 0.96 1.24 2.64 11 Internal 2.66 2.17 2.43 2.26 2.74 1.68 1.57 1.25 1.44 1.21 12 Internal 2.16 2.66 2.18 1.73 1.53 2.10 1.81 2.29 5.05 2.52 13 Internal 3.55 2.53 1.75 2.73 1.93 1.98 2.46 2.60 1.90 2.67 14 Internal 3.57 3.81 2.43 2.61 1.79 1.72 2.93 2.59 1.21 1.60 15 Internal 2.19 1.61 1.86 1.45 2.17 2.70 2.16 3.18 4.12 1.95 16 Internal 4.07 3.09 2.49 2.95 2.27 3.08 2.15 2.27 2.51 2.59 17 Internal 3.24 2.22 1.06 2.32 1.57 3.01 2.72 3.12 2.85 2.99 18 Internal 1.13 1.92 1.36 1.16 1.41 1.86 1.85 1.39 1.90 1.08 19 Internal 0.88 1.75 1.22 1.20 1.37 1.21 1.79 0.83 2.63 1.51 20 Internal 1.58 1.96 2.46 6.02 2.89 1.01 1.32 2.16 2.20 1.17 21 Control 2.58 2.18 2.81 1.74 2.16 1.98 2.61 1.08 1.64 1.65 22 Control 2.69 1.81 2.17 5.33 1.57 2.08 2.27 3.22 1.74 2.34 23 Control 2.75 2.11 1.36 1.45 1.89 1.73 1.66 2.30 1.99 1.91 24 Control 2.15 1.86 1.71 1.77 1.48 1.95 1.36 1.95 1.57 1.70 25 Control 3.24 2.21 3.07 0.72 2.51 1.94 2.56 2.81 2.44 2.88 26 Control 1.44 1.15 1.72 1.82 2.90 1.90 2.08 1.98 2.05 1.91 27 Control 4.30 5.33 2.18 2.79 1.13 0.69 3.52 1.09 2.06 0.89 28 Control 2.35 1.43 2.93 2.41 1.03 1.31 1.65 1.41 2.59 2.54 29 Control 2.18 2.82 1.21 2.02 1.31 1.48 2.19 2.18 0.73 1.47 30 Control 3.22 3.59 2.38 8.33 5.14 2.02 5.87 1.68 1.24 3.94 148 Table 44 Cereal Spilled for Acquisition 2 149 0 2 0 1 0 2 0 Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1External030010000 2 12105211 3External20 120001 4 3010126 5 External 0 0 1 1 0 100 0 3 2 1 6eral14052611 7Extn 32332233 8eral140000 0 9 External 0 0 2 0 0 40 1 0 3 0 10External0010 0 1100 0 11 Internal 0 2 0 1 1 1 1 0 1 0 12 Internal 0 1 1 1 2 2 0 3 2 1 13 Internal 3 1 5 1 1 1 3 1 4 3 14 Internal 1 1 0 0 0 1 0 2 3 1 15 Internal 0 2 4 0 1 1 1 0 0 1 16 Internal 1 1 0 1 0 0 0 2 0 2 17 Internal 6 3 1 12 0 7 11 1 0 0 18 Internal 1 0 2 0 118 0 1 0 1 0 19 Internal 2 0 1 1 0 0 1 0 1 0 20 Internal 8 24 2 5 6 17 3 5 2 0 21 Control 0 2 3 0 1 1 0 1 0 0 22 Control 0 4 20 2 2 6 13 1 5 1 23 Control 1 0 0 1 1 1 1 0 0 0 24 Control 0 0 0 0 0 0 0 0 0 0 25 Control 0 0 0 5 1 0 1 0 0 1 26 Control 0 1 1 1 1 8 3 1 1 1 27 Control 0 2 4 8 0 96 3 4 0 0 28 Control 6 0 23 0 0 1 0 2 0 0 29 Control 3 2 1 2 0 2 6 2 2 13 30 Control 25 2 0 15 2 1 3 1 0 6 Table 45 MT 1 (ms) for Retention Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 1384 1905 1766 1444 1237 1288 1527 1218 2004 1839 2 External 1022 1017 1326 749 1006 1412 946 1307 631 990 3 External 1607 1317 1660 1311 1311 995 794 769 1277 1140 4 External 2011 1820 1230 2032 1511 1727 993 1378 1214 1317 5 External 1442 1145 752 2198 1137 1815 993 1117 1055 959 6 External 1528 1625 1509 1622 1404 1744 1699 1230 1258 1269 7 External 1276 937 1123 1201 1548 1311 1341 1390 1182 1106 8 External 2244 1310 1930 5140 1480 1389 1956 1539 1394 1735 9 External 2245 3478 2404 1597 2307 2561 3805 2150 2126 5147 10 External 1929 2001 1835 1685 1580 1636 1653 2623 1367 1891 11 Internal 2558 4382 2869 2419 2392 2756 2211 1978 2176 2398 12 Internal 3099 1869 2322 3382 2237 2181 1271 2334 2125 1456 13 Internal 1236 1185 1196 1375 1357 1413 1039 1361 1224 1155 14 Internal 3009 1492 1808 1589 3860 2356 1658 1447 1485 2223 15 Internal 1686 1563 1586 2487 2522 2658 1539 1901 2898 2959 16 Internal 2740 3217 2136 2182 2000 1656 2086 3389 3284 2194 17 Internal 2898 2651 2474 2274 2338 2110 2147 2389 2596 2483 18 Internal 1675 1746 1530 1859 1495 1622 1859 2017 1830 1841 19 Internal 1222 2168 2303 1510 2192 1879 1620 1460 1397 1307 20 Internal 1854 1879 1571 1908 2430 1803 1999 1706 2183 1393 21 Control 1513 1304 1286 1586 2327 1297 1233 1550 1354 1219 22 Control 759 803 1032 998 799 627 1625 1168 965 898 23 Control 2477 1665 2384 3929 2494 1274 2352 2251 2570 2502 24 Control 1992 2036 3103 2084 3353 1985 1817 3579 1971 2243 25 Control 1624 1384 2280 2025 1624 1462 1734 1958 1659 1726 26 Control 1799 2633 1907 2065 1796 3102 3590 1901 1850 1947 27 Control 1210 1185 1558 1402 1080 1343 2269 1230 1349 1203 28 Control 1175 1788 1119 1180 1095 1359 1166 1465 1216 1097 29 Control 3632 2322 1336 1110 1454 2433 1792 1816 1924 2295 30 Control 1750 1687 2197 1727 1595 1545 1895 1595 1676 1977 150 Table 46 MT 2 (ms) for Retention Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 6792 5008 5363 6136 5951 5432 4598 5641 5261 5360 2 External 3248 3475 3433 3873 3146 3404 3335 2735 3351 1074 3 External 3876 3660 3388 4128 4128 3420 3340 3295 4413 3343 4 External 6351 7570 7880 6872 6197 10233 3107 5770 6230 6851 5 External 5354 3105 4642 4372 3099 3165 3107 2999 2978 2753 6 External 4846 4970 4755 4733 5157 4761 4704 4601 5696 4984 7 External 4998 4284 4298 4210 3672 4091 4652 4256 4445 3874 8 External 7732 10640 6500 13987 5580 5979 5497 5941 4922 4695 9 External 6182 6422 5065 7600 7355 11947 5880 12006 8627 7108 10 External 5517 2920 6617 5841 5591 5824 5939 5266 5506 4814 11 Internal 6839 6890 6844 6048 6800 9032 7153 6581 6389 6423 12 Internal 7817 4169 5246 4524 5354 4714 1692 5635 3699 4226 13 Internal 3453 3165 3930 3441 3279 3504 3215 2865 4965 3287 14 Internal 5621 6874 6198 6144 6804 8097 6055 5638 5304 6080 15 Internal 5535 5014 4630 5728 5538 5395 5837 5076 4053 5235 16 Internal 6904 6886 6448 7920 7786 6848 9010 6880 7866 7196 17 Internal 6172 5862 5665 4850 5182 6240 5304 5712 5338 5569 18 Internal 6215 6053 6034 5758 5375 5247 5397 5375 5220 5324 19 Internal 7468 18844 5054 5700 5536 5473 5267 5414 5004 4819 20 Internal 4723 8303 4024 6270 5095 5348 5320 5272 4642 6941 21 Control 4587 6053 5136 4490 3907 4388 4621 4837 4865 5037 22 Control 4799 3615 5081 4579 3907 4768 3695 3585 3930 4255 23 Control 7491 6469 7128 6674 6874 10374 7866 8245 7085 6959 24 Control 7084 6487 8331 6895 7019 6360 6482 7565 6580 7584 25 Control 5086 4811 9625 5994 2250 4919 5016 1846 1849 6840 26 Control 11186 8146 8765 6318 9570 5739 6332 8755 7455 8337 27 Control 7412 6740 4572 4166 6860 3881 3922 4310 3444 3815 28 Control 4700 4269 4527 4310 4951 4045 4970 5560 4407 4388 29 Control 4520 5929 6732 5042 5480 4012 4636 5925 6132 4552 30 Control 7400 3701 5388 4595 4900 4507 4357 4638 4455 4533 151 Table 47 MT 3 (ms) for Retention Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 3506 4375 4322 4039 4267 3860 3277 4513 4210 3725 2 External 2401 1957 2144 1952 1886 3430 1743 2263 1965 4452 3 External 2848 2766 4125 3081 3081 2800 2285 4176 2805 2163 4 External 3435 3348 3240 5130 4150 8300 2070 4354 3690 3043 5 External 2224 3395 2150 2013 1631 3360 2070 2017 2479 1982 6 External 3049 3555 3528 3451 3235 3622 2946 3103 2822 3367 7 External 2549 2667 2948 2829 2977 3051 2877 2941 2849 2981 8 External 3257 2425 2750 2821 2570 2759 3659 3350 2550 2470 9 External 4527 3490 3796 3927 5000 4298 7922 4079 4896 4063 10 External 3436 6181 3772 3361 2684 2847 2784 3308 2642 3124 11 Internal 4051 4021 4300 6028 4247 3964 5993 4343 3710 3177 12 Internal 1337 2800 2606 2743 3447 2892 11052 2718 2895 2592 13 Internal 3452 2276 2093 2832 2342 3882 2010 2686 2540 2302 14 Internal 3327 3960 4055 3794 3238 3473 3031 4374 3335 3061 15 Internal 4815 3802 3690 4950 4675 4818 4003 4100 4742 4505 16 Internal 4689 4765 4830 3946 4474 5019 4150 4340 5173 4665 17 Internal 3295 3489 3324 6750 3550 3710 5265 3743 3062 3608 18 Internal 4080 5543 4406 3670 3380 4014 4109 10892 4172 3498 19 Internal 4017 4295 3757 3090 3281 3890 3395 3145 3642 3524 20 Internal 3537 7732 2436 2838 1935 2600 2555 4940 3508 2643 21 Control 2924 2585 3130 2737 2987 2916 2874 2755 2895 3072 22 Control 2610 2671 2362 2023 3241 2777 2190 3028 1943 2623 23 Control 3668 3967 4116 4081 4223 3671 3900 4248 4175 4046 24 Control 4162 3356 4684 4595 4948 4026 4398 3747 3513 4004 25 Control 3558 3730 2645 4082 9017 3522 3416 6965 7264 3894 26 Control 3783 4009 3929 3468 3160 6079 4150 3751 3015 3404 27 Control 2208 1820 2475 3091 1640 2289 2474 2215 3627 1960 28 Control 2550 3512 2532 3320 2578 2625 2582 3600 2774 2277 29 Control 2685 3655 3237 4815 3102 2598 2949 2843 3135 2932 30 Control 2440 2807 3528 2463 3615 3411 3065 2808 2569 2968 152 Table 48 MT 4 (ms) for Retention Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 1578 1452 1848 1984 2294 1593 1558 1590 1280 1530 2 External 1020 2518 1109 865 3198 1546 1500 848 1031 1299 3 External 1152 843 1052 1043 1043 1100 799 998 511 701 4 External 1550 1696 1500 3279 1658 1632 820 1393 1447 5005 5 External 774 1373 805 750 799 1410 820 806 646 612 6 External 1242 1152 1249 1164 1525 1354 1302 1181 1053 1126 7 External 829 1231 1095 1044 1192 1105 1225 1031 1071 1429 8 External 1234 1545 1200 1460 2570 1162 1709 1486 1539 1860 9 External 869 1193 1141 1361 1298 1465 1559 1676 2323 2003 10 External 1556 1372 1292 1553 1286 1247 1290 1355 1407 1596 11 Internal 676 753 1989 1162 1153 1187 1250 1214 1112 1351 12 Internal 926 950 1430 1196 5330 1121 2895 1157 971 865 13 Internal 928 1025 1103 1123 1330 996 1100 908 1198 865 14 Internal 1195 1194 1168 1548 1299 1284 1413 1160 1198 1204 15 Internal 1050 1122 944 1023 668 1127 947 995 1503 658 16 Internal 1286 1779 2293 1222 2203 1443 1352 1643 1697 1714 17 Internal 1062 1050 1340 1163 1280 1220 1499 1279 1693 1052 18 Internal 1630 957 2228 1641 1800 1534 1608 986 897 1676 19 Internal 726 1381 639 2170 1552 1534 1603 1443 1959 2694 20 Internal 691 801 793 662 2200 786 971 950 1025 788 21 Control 1888 2357 2122 1379 1330 1488 2187 1799 1516 1773 22 Control 813 829 767 836 998 838 1698 990 697 819 23 Control 1258 1088 1315 1333 1114 1155 1248 1035 1244 1256 24 Control 1577 2191 2301 1257 1640 1345 1035 1344 1352 1433 25 Control 1521 1409 2650 674 1156 1502 1349 1414 1578 722 26 Control 1132 1278 1079 1282 1401 1835 14257 1411 1920 1411 27 Control 1010 1180 1110 748 1240 1696 1057 1140 1133 2360 28 Control 1150 1102 740 1400 787 1178 787 1350 810 1005 29 Control 1045 832 813 740 891 1084 786 891 927 739 30 Control 1610 904 841 984 1069 1205 1002 924 724 1103 153 Table 49 TMT (ms) for Retention Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 13260 12740 13299 13603 13749 12173 10960 12962 12755 12454 2 External 7691 8967 8012 7439 9236 9792 7524 7153 6978 7815 3 External 9483 8586 10225 9563 9563 8315 7218 9238 9006 7347 4 External 13347 14434 13850 17313 13516 21892 6990 12895 12581 16216 5 External 9794 9018 8349 9333 6666 9750 6990 6939 7158 6306 6 External 10665 11302 11041 10970 11321 11481 10651 10115 10829 10746 7 External 9652 9119 9464 9284 9389 9558 10095 9618 9547 9390 8 External 14467 15920 12380 23408 11930 11289 12821 12316 10405 10760 9 External 13823 14583 12406 14485 15960 20271 19166 19911 17972 18321 10 External 12438 12474 13516 12440 11141 11554 11666 12552 10922 11425 11 Internal 14124 16046 16002 15657 14592 16939 16607 14116 13387 13349 12 Internal 13179 9788 11604 11845 16368 10908 16910 11844 9690 9139 13 Internal 9069 7651 8322 8771 8308 9795 7364 7820 9927 7609 14 Internal 13152 13520 13229 13075 15201 15210 12157 12619 11322 12568 15 Internal 13086 11501 10850 14188 13403 13998 12326 12072 13196 13357 16 Internal 15619 16647 15707 15270 16463 14966 16598 16252 18020 15769 17 Internal 13427 13052 12803 15037 12350 13280 14215 13123 12689 12712 18 Internal 13600 14299 14198 12928 12050 12417 12973 19270 12119 12339 19 Internal 13433 26688 11753 12470 12561 12776 11885 11462 12002 12344 20 Internal 10805 18715 8824 11678 11680 10537 10845 12868 11358 11765 21 Control 10912 12299 11674 10192 10551 10089 10915 10941 10630 11101 22 Control 8981 7918 9242 8436 8945 9010 9208 8771 7535 8595 23 Control 14894 13189 14943 16017 14705 16474 15366 15779 15074 14763 24 Control 14815 14070 18419 14831 16960 13716 13732 16235 13416 15264 25 Control 11789 11334 17200 12775 14047 11405 11515 12183 12350 13182 26 Control 17900 16066 15680 13133 15927 16755 28329 15818 14240 15099 27 Control 11840 10925 9715 9407 10820 9209 9722 8895 9553 9338 28 Control 9675 10671 8918 10210 9411 9207 9505 11975 9207 8767 29 Control 11882 12738 12118 11707 10927 10127 10163 11475 12118 10518 30 Control 13200 9099 11954 9769 11179 10668 10319 9965 9424 10581 154 Table 50 TMU for Retention Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 54 61 64 57 57 49 52 58 65 49 2 External 16 18 14 17 21 15 14 11 13 15 3 External 19 17 25 21 21 23 14 17 21 16 4 External 33 27 33 34 28 54 26 23 22 37 5 External 44 58 25 34 22 68 26 26 28 23 6 External 42 44 39 37 43 46 40 39 44 36 7 External 38 38 43 44 40 39 43 39 32 33 8 External 69 96 131 100 57 51 67 55 40 53 9 External 59 76 59 46 67 80 92 104 68 79 10 External 59 54 62 55 50 47 52 67 41 49 11 Internal 31 36 34 33 36 42 36 33 26 30 12 Internal 31 21 27 26 31 21 37 24 25 19 13 Internal 26 16 16 14 18 17 26 16 18 14 14 Internal 32 30 31 28 36 30 28 31 22 28 15 Internal 28 24 21 32 34 34 24 27 32 33 16 Internal 76 98 66 59 67 54 63 71 81 61 17 Internal 65 58 63 66 63 60 56 69 54 61 18 Internal 60 64 56 45 89 57 58 83 43 49 19Internal501205250494752475049 20 Internal 47 70 35 46 67 33 45 57 53 40 21Control19231817221821221618 2Control19202319222021211616 23Control35252939362732343631 24Control26302929372832422532 25Control23229326332325171928 26Control848766536177150645355 27Control76827627693345694562 28Control50624179384636914031 29Control71553532474246454950 30 Control 112 36 54 38 51 46 56 44 43 54 155 Table 51 Pitch (deg) for Retention Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 2.26 3.76 1.81 1.68 2.93 3.75 3.19 3.58 3.76 3.99 2 External 2.78 4.68 3.28 3.05 7.18 3.70 3.87 2.65 2.75 3.80 3 External 4.17 1.41 1.70 1.43 1.43 1.70 1.24 1.25 1.00 1.43 4 External 3.39 3.39 2.36 3.51 3.17 3.14 2.83 3.12 2.42 4.68 5 External 0.94 0.70 2.31 1.90 1.46 0.95 2.83 3.42 2.25 2.82 6 External 1.58 3.12 1.95 3.02 3.73 2.94 3.06 4.52 2.80 4.07 7 External 2.69 1.95 1.08 1.08 1.27 4.93 0.80 1.03 1.07 2.15 8 External 4.18 5.80 6.13 3.53 6.91 3.29 5.69 3.97 2.22 7.83 9 External 1.65 4.23 4.58 2.12 3.07 1.54 2.02 5.13 1.96 2.16 10 External 4.01 1.97 4.01 3.33 2.66 2.87 2.92 3.47 2.43 3.38 11 Internal 0.78 3.35 2.67 2.99 2.91 4.08 4.10 2.38 4.26 4.31 12 Internal 2.01 1.17 1.87 2.63 4.27 2.08 8.66 2.11 3.66 3.04 13 Internal 0.93 2.16 1.48 1.81 2.27 2.83 1.81 1.38 3.25 2.79 14 Internal 1.18 1.62 1.49 0.98 1.74 2.27 2.34 1.32 1.88 1.51 15 Internal 1.37 2.13 2.68 3.39 2.49 2.77 1.58 2.73 0.95 1.70 16 Internal 3.88 3.45 3.02 2.84 3.99 2.73 2.69 2.75 3.00 1.93 17 Internal 2.13 2.32 3.92 3.34 1.89 1.48 3.03 2.77 4.43 1.15 18 Internal 3.37 3.97 3.88 2.26 3.15 3.50 4.58 3.08 4.98 4.74 19 Internal 2.45 2.86 1.97 1.85 1.22 1.34 1.16 1.70 2.65 8.23 20 Internal 2.85 2.11 2.33 0.91 1.62 1.85 4.07 4.14 1.57 3.67 21 Control 4.20 5.07 3.43 4.84 4.29 6.58 4.93 5.98 3.15 5.37 22 Control 1.05 3.22 2.09 1.36 2.85 1.77 3.07 2.84 2.84 1.85 23 Control 2.30 3.56 2.59 2.65 1.70 2.96 3.07 2.45 3.12 2.72 24 Control 2.99 3.60 2.12 2.77 17.23 3.07 4.28 1.94 2.18 2.05 25 Control 4.67 3.70 1.70 4.67 2.19 2.05 2.56 1.17 2.39 0.43 26 Control 0.42 0.71 1.49 2.35 1.69 3.47 5.99 0.94 1.21 3.96 27 Control 0.34 0.70 1.25 2.31 2.22 2.23 4.11 1.00 3.46 1.84 28 Control 3.82 4.48 3.51 4.15 3.54 1.88 3.17 6.21 1.74 3.10 29 Control 1.31 1.66 2.12 1.54 2.07 3.20 1.85 2.52 2.13 2.79 30 Control 1.57 1.40 1.41 3.47 5.48 3.35 2.89 2.05 2.53 2.44 156 Table 52 Roll (deg) for Retention Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 2.93 2.51 1.75 2.44 1.38 1.89 2.70 2.76 1.10 2.56 2 External 4.23 1.89 1.90 2.96 3.64 2.23 2.16 3.30 2.55 2.21 3 External 2.30 2.76 2.14 0.84 0.84 1.40 1.71 1.66 0.91 1.97 4 External 1.28 2.62 1.39 1.68 2.43 3.96 2.82 1.43 1.87 2.53 5 External 3.22 1.02 3.52 3.08 2.35 1.13 2.82 0.88 2.43 3.13 6 External 5.26 2.03 2.35 1.48 1.35 2.23 1.19 1.64 1.49 1.38 7 External 2.01 2.34 1.51 1.95 2.84 1.91 1.58 1.85 1.52 2.36 8 External 3.44 2.62 2.71 2.64 1.21 1.98 1.15 2.30 2.94 2.00 9 External 1.67 1.83 1.60 1.19 2.87 2.16 2.34 3.79 2.04 4.94 10 External 2.97 1.62 1.09 0.83 1.48 0.92 1.04 0.82 2.02 1.25 11 Internal 2.42 3.68 2.16 1.76 2.21 0.87 0.79 1.23 1.31 1.13 12 Internal 0.86 3.27 1.85 2.38 4.69 1.04 3.77 2.72 0.96 2.00 13 Internal 1.80 1.97 1.90 1.31 2.38 2.10 2.51 1.17 2.33 2.24 14 Internal 2.54 2.75 1.88 2.80 4.08 3.25 2.30 2.35 2.89 2.56 15 Internal 4.80 2.31 4.02 3.05 0.77 1.63 1.85 1.37 2.85 1.16 16 Internal 1.77 1.93 1.52 2.44 2.04 1.88 2.03 1.72 1.98 2.50 17 Internal 2.93 3.13 3.82 1.66 2.78 3.62 2.44 2.28 2.72 3.58 18 Internal 1.87 2.16 1.72 2.34 2.16 2.15 1.41 2.18 1.33 2.56 19 Internal 0.59 1.29 2.98 1.90 2.02 1.29 1.18 2.10 1.03 4.01 20 Internal 2.65 2.40 0.94 1.78 1.99 1.84 2.26 2.50 2.04 1.39 21 Control 5.74 3.95 1.74 5.04 3.83 4.70 1.88 4.09 2.05 3.36 22 Control 4.27 1.64 2.79 3.05 1.30 2.29 3.00 2.80 2.03 2.28 23 Control 2.38 2.35 1.62 1.83 2.29 2.20 1.81 2.44 1.84 2.09 24 Control 1.59 1.59 2.10 1.10 1.38 0.81 1.26 1.69 1.37 1.64 25 Control 3.08 1.46 2.21 1.57 2.50 3.09 1.83 3.36 2.46 1.20 26 Control 2.21 1.90 2.31 2.96 3.00 3.09 4.08 1.89 2.09 2.92 27 Control 0.62 2.57 2.86 2.19 2.20 1.56 3.70 0.83 2.23 1.55 28 Control 1.33 1.95 2.53 1.95 1.75 1.47 2.19 2.01 1.87 2.00 29 Control 1.69 1.65 1.66 2.21 2.07 2.42 1.79 1.42 2.05 1.72 30 Control 2.34 1.98 2.25 3.14 3.96 5.55 3.15 3.11 2.10 1.95 157 Table 53 Amount Spilled for Retention Subject Group Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9 Trial 10 1 External 1 0 0 2 1 5 1 2 0 0 2 External 0 0 0 0 0 1 0 0 0 0 3 External 0 0 1 0 2 0 2 5 2 0 4 External 3 2 7 0 1 2 0 1 0 0 5 External 0 1 0 0 0 0 0 0 0 0 6 External 2 1 2 0 1 0 0 0 0 2 7External1113311213 2 8 External 0 0 0 0 0 1 0 1 0 1 9 External 2 8 1 13 4 0 1 0 7 0 10External000700020 0 1Internal100001001 0 12Internal200012101 2 13Internal4021320200 2 14Internal1110801223 3 15Internal111112010 1 16Internal111110001 0 17Internal101003205 0 18Internal110100201 0 19 Internal 0 22 1 0 0 0 0 0 0 0 20Internal3181342100 9 21 Control 0 1 0 2 0 0 2 1 2 0 22 Control 5 2 3 16 2 5 11 6 2 2 23 Control 0 1 1 0 1 0 0 1 0 0 24 Control 0 0 0 0 0 0 0 0 0 0 25 Control 0 1 0 4 0 0 0 2 5 0 26 Control 9 11 1 0 2 0 1 0 1 3 27Control89110012110 0 28 Control 0 0 1 4 0 1 1 1 0 1 29 Control 1 3 7 0 0 4 3 2 2 2 30 Control 0 2 2 0 1 3 0 1 1 2 158 159 APPENDIX D ANOVA SUMMARY TABLES 160 Table 54 Acquisition MT1 Acquisition MT1 Multivariate Tests(c) Effect (Wilks? Lamda) Value F Hypothesis df Error df Sig. Partial Eta Squared Observed Power(a) Sessions .815 6.113(b) 1.000 27.000 .020 .185 .664 Sessions * Group .799 3.395(b) 2.000 27.000 .048 .201 .589 Trials .359 3.762(b) 9.000 19.000 .007 .641 .938 Trials * Group .395 1.248(b) 18.000 38.000 .275 .371 .679 Sessions * Trials .680 .995(b) 9.000 19.000 .476 .320 .344 Sessions * Trials * Group .327 1.578(b) 18.000 38.000 .117 .428 .807 a Computed using alpha = .05 b Exact statistic c Design: Intercept+Group; Within Subjects Design: Sessions+Trials+Sessions*Trials Tests of Between-Subjects Effects Transformed Variable: Average Source Type III Sum of Squares df Mean Square F Sig. Partial Eta Squared Observed Power(a) Intercept 2249926398.960 1 2249926398.960 476.452 .000 .946 1.000 Group 9079940.530 2 4539970.265 .961 .395 .066 .199 Error 127500725.610 27 4722249.097 a Computed using alpha = .05 Table 55 Acquisition MT2 MT2 Multivariate Tests(c) Effect (Wilks? Lamda) Value F Hypothesis df Error df Sig. Partial Eta Squared Observed Power(a) Sessions .411 38.625(b) 1.000 27.000 .000 .589 1.000 Sessions * Group .958 .596(b) 2.000 27.000 .558 .042 .139 Trials .188 9.112(b) 9.000 19.000 .000 .812 1.000 Trials * Group .525 .801(b) 18.000 38.000 .686 .275 .443 Sessions * Trials .406 3.084(b) 9.000 19.000 .019 .594 .874 Sessions * Trials * Group .442 1.063(b) 18.000 38.000 .422 .335 .588 a Computed using alpha = .05 b Exact statistic c Design: Intercept+Group; Within Subjects Design: Sessions+Trials+Sessions*Trials 161 MT2 Tests of Between-Subjects Effects Transformed Variable: Average Source Type III Sum of Squares df Mean Square F Sig. Partial Eta Squared Observed Power(a) Intercept 23796035789.127 1 23796035789.127 674.042 .000 .961 1.000 Group 129733396.093 2 64866698.047 1.837 .179 .120 .349 Error 953194312.980 27 35303493.073 a Computed using alpha = .05 Table 56 Acquisition MT3 MT3 Tests of Between-Subjects Effects Effect (Wilks? Lamda) Value F Hypothesis df Error df Sig. Partial Eta Squared Observed Power(a) Sessions .645 14.869(b) 1.000 27.000 .001 .355 .960 Sessions * Group .897 1.552(b) 2.000 27.000 .230 .103 .300 Trials .280 5.419(b) 9.000 19.000 .001 .720 .991 Trials * Group .577 .669(b) 18.000 38.000 .818 .241 .365 Sessions * Trials .681 .990(b) 9.000 19.000 .479 .319 .342 Sessions * Trials * Group .373 1.344(b) 18.000 38.000 .217 .389 .721 a Computed using alpha = .05 b Exact statistic c Design: Intercept+Group; Within Subjects Design: Sessions+Trials+Sessions*Trials Acquisition MT3 Tests of Between-Subjects Effects Transformed Variable: Average Source Type III Sum of Squares df Mean Square F Sig. Partial Eta Squared Observed Power(a) Intercept 12627928688.802 1 12627928688.802 558.787 .000 .954 1.000 Group 160066673.853 2 80033336.927 3.541 .043 .208 .609 Error 610168736.395 27 22598842.089 a Computed using alpha = .05 162 Table 57 Acquisition MT4 MT4 Multivariate Tests(c) Effect (Wilks? Lamda) Value F Hypothesis df Error df Sig. Partial Eta Squared Observed Power(a) Sessions .672 13.169(b) 1.000 27.000 .001 .328 .938 Sessions * Group .867 2.062(b) 2.000 27.000 .147 .133 .387 Trials .410 3.038(b) 9.000 19.000 .020 .590 .868 Trials * Group .509 .848(b) 18.000 38.000 .637 .287 .470 Sessions * Trials .575 1.561(b) 9.000 19.000 .198 .425 .537 Sessions * Trials * Group .415 1.167(b) 18.000 38.000 .334 .356 .641 a Computed using alpha = .05 b Exact statistic c Design: Intercept+Group; Within Subjects Design: Sessions+Trials+Sessions*Trials MT4 Tests of Between-Subjects Effects Transformed Variable: Average Source Type III Sum of Squares df Mean Square F Sig. Partial Eta Squared Observed Power(a) Intercept 1313591839.935 1 1313591839.935 536.912 .000 .952 1.000 Group 2024281.720 2 1012140.860 .414 .665 .030 .110 Error 66057380.795 27 2446569.659 a Computed using alpha = .05 Table 58 Acquisition TMT TMT Multivariate Tests(c) Effect (Wilks? Lamda) Value F Hypothesis df Error df Sig. Partial Eta Squared Observed Power(a) Sessions .341 52.075(b) 1.000 27.000 .000 .659 1.000 Sessions * Group .866 2.083(b) 2.000 27.000 .144 .134 .390 Trials .129 14.305(b) 9.000 19.000 .000 .871 1.000 Trials * Group .325 1.595(b) 18.000 38.000 .112 .430 .812 Sessions * Trials .458 2.495(b) 9.000 19.000 .045 .542 .780 Sessions * Trials * Group .543 .753(b) 18.000 38.000 .737 .263 .414 a Computed using alpha = .05 b Exact statistic c Design: Intercept+Group; Within Subjects Design: Sessions+Trials+Sessions*Trials 163 TMT Tests of Between-Subjects Effects Transformed Variable: Average Source Type III Sum of Squares df Mean Square F Sig. Partial Eta Squared Observed Power(a) Intercept 122681502118.282 1 122681502118.282 840.057 .000 .969 1.000 Group 760401282.223 2 380200641.112 2.603 .092 .162 .474 Error 3943068449.245 27 146039572.194 a Computed using alpha = .05 Table 59 Acquisition TMU TMU Multivariate Tests(c) Effect (Wilks? Lamda) Value F Hypothesis df Error df Sig. Partial Eta Squared Observed Power(a) Sessions .493 27.798(b) 1.000 27.000 .000 .507 .999 Sessions * Group .814 3.094(b) 2.000 27.000 .062 .186 .548 Trials .269 5.748(b) 9.000 19.000 .001 .731 .994 Trials * Group .380 1.315(b) 18.000 38.000 .233 .384 .709 Sessions * Trials .462 2.455(b) 9.000 19.000 .048 .538 .772 Sessions * Trials * Group .661 .485(b) 18.000 38.000 .949 .187 .259 a Computed using alpha = .05 b Exact statistic c Design: Intercept+Group; Within Subjects Design: Sessions+Trials+Sessions*Trials TMU Tests of Between-Subjects Effects Transformed Variable: Average Source Type III Sum of Squares df Mean Square F Sig. Partial Eta Squared Observed Power(a) Intercept 1641801.660 1 1641801.660 168.358 .000 .862 1.000 Group 18810.120 2 9405.060 .964 .394 .067 .200 Error 263299.620 27 9751.838 a Computed using alpha = .05 164 Table 60 Acquisition Pitch Pitch Multivariate Tests(c) Effect (Wilks? Lamda) Value F Hypothesis df Error df Sig. Partial Eta Squared Observed Power(a) Sessions .995 .134(b) 1.000 27.000 .718 .005 .064 Sessions * Group .981 .258(b) 2.000 27.000 .774 .019 .087 Trials .591 1.463(b) 9.000 19.000 .231 .409 .505 Trials * Group .451 1.033(b) 18.000 38.000 .449 .329 .573 Sessions * Trials .710 .861(b) 9.000 19.000 .573 .290 .297 Sessions * Trials * Group .447 1.045(b) 18.000 38.000 .437 .331 .579 a Computed using alpha = .05 b Exact statistic c Design: Intercept+Group; Within Subjects Design: Sessions+Trials+Sessions*Trials Pitch Tests of Between-Subjects Effects Transformed Variable: Average Source Type III Sum of Squares df Mean Square F Sig. Partial Eta Squared Observed Power(a) Intercept 4446.278 1 4446.278 300.403 .000 .918 1.000 Group 55.241 2 27.620 1.866 .174 .121 .354 Error 399.628 27 14.801 a Computed using alpha = .05 Table 61 Acquisition Roll Roll Multivariate Tests(c) Effect (Wilks? Lamda) Value F Hypothesis df Error df Sig. Partial Eta Squared Observed Power(a) Sessions .828 5.594(b) 1.000 27.000 .025 .172 .626 Sessions * Group .956 .627(b) 2.000 27.000 .542 .044 .144 Trials .537 1.817(b) 9.000 19.000 .131 .463 .615 Trials * Group .481 .933(b) 18.000 38.000 .548 .306 .518 Sessions * Trials .645 1.164(b) 9.000 19.000 .370 .355 .403 Sessions * Trials * Group .642 .524(b) 18.000 38.000 .929 .199 .280 a Computed using alpha = .05 b Exact statistic c Design: Intercept+Group; Within Subjects Design: Sessions+Trials+Sessions*Trials 165 Roll Tests of Between-Subjects Effects Transformed Variable: Average Source Type III Sum of Squares df Mean Square F Sig. Partial Eta Squared Observed Power(a) Intercept 3233.144 1 3233.144 665.982 .000 .961 1.000 Group 2.144 2 1.072 .221 .803 .016 .081 Error 131.077 27 4.855 a Computed using alpha = .05 Table 70 Retention MT1 Tests of Between-Subjects Effects Transformed Variable: Average Source Type III Sum of Squares df Mean Square F Sig. Partial Eta Squared Observed Power(a) Intercept 980608576.65 3 1 980608576.65 3 429.875 .000 .941 1.000 Group 11153475.047 2 5576737.523 2.445 .106 .153 .449 Error 61591067.900 27 2281150.663 a Computed using alpha = .05 Table 71 Retention MT2 Tests of Between-Subjects Effects Transformed Variable: Average Source Type III Sum of Squares df Mean Square F Sig. Partial Eta Squared Observed Power(a) Intercept 980608576.65 3 1 980608576.65 3 429.875 .000 .941 1.000 Group 11153475.047 2 5576737.523 2.445 .106 .153 .449 Error 61591067.900 27 2281150.663 a Computed using alpha = .05 166 Table 72 Retention MT3 Tests of Between-Subjects Effects Transformed Variable: Average Source Type III Sum of Squares df Mean Square F Sig. Partial Eta Squared Observed Power(a) Intercept 3706771372.8 04 1 3706771372.8 04 686.902 .000 .962 1.000 Group 21903530.647 2 10951765.323 2.029 .151 .131 .381 Error 145701717.05 0 27 5396359.891 a Computed using alpha = .05 Table 73 Retention MT4 Tests of Between-Subjects Effects Transformed Variable: Average Source Type III Sum of Squares df Mean Square F Sig. Partial Eta Squared Observed Power(a) Intercept 552562265.36 3 1 552562265.36 3 338.028 .000 .926 1.000 Group 259268.987 2 129634.493 .079 .924 .006 .061 Error 44135911.950 27 1634663.406 a Computed using alpha = .05 Table 74 Retention TMT Tests of Between-Subjects Effects Transformed Variable: Average Source Type III Sum of Squares df Mean Square F Sig. Partial Eta Squared Observed Power(a) Intercept 44726157964. 814 1 44726157964. 814 664.184 .000 .961 1.000 Group 122834151.48 7 2 61417075.743 .912 .414 .063 .191 Error 1818181081.9 00 27 67340040.070 a Computed using alpha = .05 167 Table 75 Retention TMU Tests of Between-Subjects Effects Transformed Variable: Average Source Type III Sum of Squares df Mean Square F Sig. Partial Eta Squared Observed Power(a) Intercept 554356.053 1 554356.053 158.502 .000 .854 1.000 Group 188.207 2 94.103 .027 .973 .002 .054 Error 94431.540 27 3497.464 a Computed using alpha = .05 Table 76 Retention Pitch Tests of Between-Subjects Effects Transformed Variable: Average Source Type III Sum of Squares df Mean Square F Sig. Partial Eta Squared Observed Power(a) Intercept 2420.742 1 2420.742 318.301 .000 .922 1.000 Group 4.514 2 2.257 .297 .746 .022 .092 Error 205.341 27 7.605 a Computed using alpha = .05 Table 77 Retention Roll Tests of Between-Subjects Effects Transformed Variable: Average Source Type III Sum of Squares df Mean Square F Sig. Partial Eta Squared Observed Power(a) Intercept 1476.505 1 1476.505 641.129 .000 .960 1.000 Group 2.359 2 1.179 .512 .605 .037 .125 Error 62.180 27 2.303 a Computed using alpha = .05