Date of Award

Summer 2021

Document Type

Open Access Dissertation

Department

Exercise Science

First Advisor

Troy Herter

Abstract

Acquiring, refining, and adapting motor skills allows for successful interaction with our environment to perform daily activities such as driving, cooking, and self-care. Those with stroke often exhibit a compromised ability to relearn motor skills affected by their stroke resulting in chronic disability. Previous rehabilitation studies suggest that deficits in skilled limb movement primarily contributes to deficits after a stroke. However, studies in motor skill performance suggests that multiple behavioral features including visual search, eye-hand coordination and visuomotor decisions also contribute to improved performance. Currently, it is not known if refinements in multiple behavioral features independently contribute to motor learning, resulting in a lack of knowledge of how impairments in each behavioral feature contributes to deficits in motor learning after a stroke. In the current study, we used an ethological approach to test the hypotheses that practice-related refinements of multiple behavioral features are independently predictive of motor learning and that deficits in multiple behavioral features are independently predictive of motor impairments in stroke. Healthy individuals and those with a single cerebral stroke used an upper-limb robot with eye tracking to practice six trials of a continuous object hit-and-avoidance task once a week for six consecutive weeks. Participants were instructed to use virtual paddles to hit away 200 target objects and avoided hitting 100 distractor objects that continuously moved towards them from the back of the workspace. Motor learning was inferred from trial-by-trial acquisition and week-by-week retention of improvements on two measures of task performance related to motor execution and motor inhibition. In healthy individuals, refinements in skilled limb movement, visual search, and eye-hand coordination were independently predictive of improvements in motor execution, while refinements in eye-hand coordination was independently predictive of improvements in motor inhibition. In those with stroke, deficits in skilled limb movement, visual search, and eye-hand coordination were independently predictive of impairments in motor execution, while deficits in skilled limb movements and eye-hand coordination were predictive of impairments in motor inhibition. These results provide evidence that practice-related refinements in multiple behavioral features may independently contribute to motor learning and should be considered for inclusion in stroke rehabilitation interventions.

Rights

© 2021, Christopher Michael Perry

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