In partial fulfillment of the requirements for the degree of

Doctor of Philosophy in Applied Physiology

In the

School of Biological Sciences

EVAN SANDLER

Will defend his dissertation

AFFERENT STIMULATION FOR THE REDUCTION OF SPASTICITY

IN PERSONS WITH SPINAL CORD INJURY

13TH OF NOVEMBER, 2024

9:00 AM

Applied Physiology Building (555 14th St.), Room 1253

Thesis Advisor:

Edelle Field-Fote, PT, Ph.D.

School of Biological Sciences

Georgia Institute of Technology

Committee Members:

T. Richard Nichols, Ph.D.

School of Biological Sciences

Georgia Institute of Technology

Karen Minassian, Ph.D.

Center for Medical Physics and Biomedical Engineering

Medical University of Vienna

Mark Lyle, DPT, Ph.D.

Department of Rehabilitation Medicine

Emory University

Boris Prilutsky, Ph.D.

School of Biological Sciences

Georgia Institute of Technology

ABSTRACT: Afferent stimulation represents a neuromodulatory therapeutic intervention that avoids the negative side effects associated with pharmaceuticals. Recent studies suggest that transcutaneous spinal stimulation (TSS) may hold therapeutic promise for reducing spasticity in individuals with spinal cord injury (SCI). Despite evidence that this non-invasive stimulation targets the most likely mechanisms underlying spasticity, the optimal stimulation parameters required to produce antispasmodic effects are unknown. Moreover, systematic comparison and dose-response studies are fundamental in identifying efficacy of promising interventions. I will outline the results of my research to provide insight into foundational elements of this emerging therapeutic intervention for individuals with SCI in three parts. First, I will discuss the efficacy of mechanical and electrical stimulation interventions on reducing spasticity of the quadriceps. Second, I will present the effects of three different spinal stimulation conditions on biomechanical measures of spasticity at the knee and ankle relative to clinical application. And third, I will present the effects of spinal stimulation on electrophysiologic measures of spasticity to elucidate the relationship between biomechanical and electrophysiologic measures.