All ETDs from UAB

Advisory Committee Chair

Christopher P Hurt

Advisory Committee Members

Harrison Walker

William R Reed

Noah J Rosenblatt

Kristina Visscher

Document Type

Dissertation

Date of Award

2021

Degree Name by School

Doctor of Philosophy (PhD) School of Public Health

Abstract

Human locomotion often occurs through environments with complex sets of external demands (e.g., obstacles, uneven surfaces, altered terrain, etc.). Fortunately, humans have developed locomotor systems capable of rapidly adapting gait patterns to navigate these environments. Advanced age and neurological disorders such as Parkinson’s disease (PD) are associated with physiological changes that add to the complexity of locomotion – these individuals must not only adapt to changing environmental demands, but also to changes in internal function (e.g., reduced muscle strength, dysfunctional sensorimotor integration). While there is a growing body of literature indicating that healthy older adults maintain adaptability, less is known about the effects of PD on this gait feature. This dissertation used a variety of experimental and analytical approaches to describe the effects of both healthy aging and PD on gait adaptability. We first compared joint-level kinetics between healthy older adults and PD patients walking at their self-selected comfortable and maximal speeds. We found that healthy older adults, but not PD patients, adapted joint-level kinetics to reach maximal walking speeds and noted that inability to appropriately adapt mechanics may limit the extent to which individuals with PD can speed up. We then supported these findings in a separate cohort completing a more controlled experimental protocol where individuals walked at a range of matched rather than self-selected speeds. In a third study, we confirmed high levels of gait adaptability with healthy aging by showing comparable rates of kinematic adaptation to split-belt treadmill walking under both normal and sensory-disrupted conditions in younger and older adults. Combined, results from this dissertation confirm that gait adaptability is maintained with healthy aging but not PD. Loss of gait adaptability has important functional consequences, including a reduced community ambulation and mobility. These results have important clinical implications. First, interventions aimed at reducing the extent to which healthy older adults adapt joint-level kinetics should consider that age-related adaptations are beneficial rather than detrimental in nature. Second, our results suggest that gait adaptability should be treated as target of interventions for individuals with PD.

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