This Is AuburnElectronic Theses and Dissertations

The Effect of Event Boundaries on Repetition Reduction Among Individuals with Previous Experience of mTBI




Siegel, Julia

Type of Degree

Master's Thesis


Speech, Language, and Hearing Sciences


Previous research has shown that event boundaries have a ‘reset’ effect on repetition reduction within conversational speech. Other studies have shown that the ‘Location Updating Effect’ impacts memory, even within a virtual environment. However, these two ideas have only been examined separately, within a typical population of participants. The present study examined the effect of event boundaries on repetition reduction among individuals who have a history of mTBI, within a virtual environment. It was hypothesized that the effect of event boundaries would be less extensive among the concussion group, due to potential mild deficits in motor speech and memory. Ten individuals participated in the study (5 with previous experience of mTBI, 5 typical, without history of mTBI). Participants produced 8 stories (4 all within a single room, and 4 with a change in rooms in the middle) that included 10 target phrases. Each target phrase was measured for duration, pitch range, and articulatory-acoustic vowel space (AAVS) to determine any changes following room change. Data revealed no significant group differences between the concussion group and the typical group following a room change. When all participants were analyzed together, however, there was evidence of repetition reduction within a single room, but decreased reduction immediately following a room change. This supports the hypothesis that speech can be affected by event boundaries through perceptual engagement in a virtual environment alone.