Locomotor Control Mechanisms in Older Adults and People with Essential Tremor

Abstract

This dissertation explored locomotor control strategies in older adults and individuals with Essential Tremor. The first aim was to investigate the impact of age on gait flexibility, focusing on spatial and temporal control. The study involved nineteen healthy older and younger adults walking on a split-belt treadmill, where the non-dominant leg moved twice as fast as the dominant leg. While both age groups adapted their gait similarly to the differing belt speeds, older adults used less timing strategies than their younger counterparts, with no notable differences in spatial strategies. The second aim examined the ability of people with Essential Tremor to perform postural transition movements and allocate and prioritize attentional resources when attention is divided. To investigate postural transition movement performance, 19 people with and without Essential Tremor completed a standard Timed Up and Go (TUG) and a more complex water-carry TUG. Phases of these TUG tasks (sit-to-stand, straight-line walk, turn, and stand-to-sit) reflect these postural transition movements and were compared between the Essential Tremor and Non-Essential Tremor groups. People with Essential Tremor depicted impaired performance in each phase of the standard and water-carry TUG, indicating functional movement deficits that may compromise everyday ambulation. To compare attention allocation performance in people with and without Essential Tremor, participants completed a dual-task standard and water-carry TUG in which they simultaneously completed a talking task. This created a competition for attentional resources and permitted the investigation of dual-task effects and task prioritization. The simultaneous performance of two tasks during the standard and water-carry TUG did not differentially affect motor or cognitive performance in people with Essential Tremor compared to people without Essential Tremor. Further, people with Essential Tremor, like the non-Essential Tremor group, allocated more attention and prioritized the cognitive task over the motor task in the standard and water-carry TUG. These studies have important implications for understanding locomotor control in older adults and individuals with Essential Tremor. They provide valuable insights into movement impairments and are a crucial initial step in developing patient-centered and targeted therapeutic approaches.