In partial fulfillment of the requirements for the degree of
Doctor of Philosophy in Applied Physiology
In the
School of Biological Sciences
Jacob Spencer
Will defend his dissertation
Comparison of Changes in Neuromotor Excitability and Gait Biomechanics Induced by Gait Training With and Without Functional Electrical Stimulation
06, November 2024
9:00 AM
Price Gilbert Memorial Library (260 4th Street NW) Room 4222
https://gatech.zoom.us/j/94931589520
Thesis Advisor:
Dr. Trisha Kesar, PT, Ph.D.
Department of Rehabilitation Medicine
Emory University
Committee Members:
Dr. Lewis Wheaton, Ph.D.
School of Biological Sciences
Georgia Institute of Technology
Dr. Richard Nichols, Ph.D.
School of Biological Sciences
Georgia Institute of Technology
Dr. Michael Borich, DPT, Ph.D.
Department of Rehabilitation Medicine
Emory University
Dr. Jessica Cassidy, DPT, Ph.D.
Department of Health Sciences
The University of North Carolina at Chapel Hill
ABSTRACT: Functional electrical stimulation (FES) involves the use of electrical stimulation to facilitate or augment functional movements such as reaching or gait. FES is commonly used as a standalone or adjunctive treatment tool during rehabilitation of a diverse array of neuro-pathologies, including stroke, traumatic brain injury, and multiple sclerosis. Despite the popularity of FES in clinical practice, as well as strong evidence supporting its orthotic (i.e. immediate) and therapeutic (i.e. long-term) benefits, there are still outstanding questions concerning the potential neural mechanisms of action of FES. Because FES is often used to supplement other interventions, such as overground or treadmill-based gait training, which can independently elicit changes in neuromotor excitability, there is a need to understand the individual and synergistic effects of FES on neuromotor circuitry. This thesis summarizes the results of two studies designed to further our scientific understanding of the neural mechanisms underlying FES-assisted gait training. The purpose of the first study was to compare acute effects of 30 minutes of fast walking (Fast) and 30 minutes of fast walking with functional electrical stimulation of the ankle plantarflexors and dorsiflexors (FastFES) in 14 able-bodied young adults. Immediately before and after training, we evaluated corticomotor excitability measured using motor evoked potentials (MEPs) elicited in response to transcranial magnetic stimulation, monosynaptic spinal reflex excitability measured using Hoffman’s or H-reflexes, and propulsive force generation during gait measured by anterior ground reaction forces (AGRF). The purpose of the second study was to compare acute changes in corticomotor excitability measured by MEP amplitude, cortical inhibition measured by cortical silent period duration(CSP), and propulsive force generation during gait measured by AGRFs, induced by 30 minutes of Fast gait training versus 30 minutes of FastFES gait training in 16 individuals with chronic stroke. Our long-term goal is to combine measures of neuromotor excitability with measures of gait function, in order to illuminate the neural mechanisms underlying response to Fast and FastFES, and identify baseline characteristics of potential responders and non-responders.