Date of Award

Fall 8-13-2024

Embargo Period

8-12-2024

Document Type

Dissertation - MUSC Only

Degree Name

Doctor of Philosophy (PhD) in Health & Rehabilitation Science

Department

Health Sciences and Research

College

College of Health Professions

First Advisor

Chris Gregory

Second Advisor

John Kindred

Third Advisor

Kirstin-Friederike Heise

Fourth Advisor

Mark Bowden

Abstract

Paired associative stimulation (PAS) is an assay of sensorimotor plasticity that can account for individual differences in post-stroke sensorimotor communication. The objective of this study was to determine the effectiveness of individualized lower extremity (LE) PAS in healthy and post-stroke (>6 months), and the relationship to sensorimotor function. PAS was individualized by measuring cortical-level afferent pathways via a somatosensory evoked potential (SEP). The SEP latency (at 34ms) was then systematically paired with single transcranial magnetic stimulation (TMS) pulses to determine the individual-level timing. Relative changes in PAS-induced motor-evoked potential amplitude (MEPAmp) targeting the non-dominant (healthy) and paretic tibialis anterior muscle (stroke), for were used to quantify sensorimotor plasticity. In healthy controls (n=10; 7F/3M; age=59 [43-71] years) changes in MEPAmpwere not associated between visits (r=0.14; p=0.9792), despite significant increases in MEPAmp in Visits 2 (42.78 [7.30-350.72]%, p=0.0020) and 3 (40.36 [15.30-204.20]%, p=0.0039). In stroke (n=7; 2F/5M; age=69 [51-77] years) there was no significant relationship between visits (r=0.21; p=0.7184). We observed significant increases in MEPAmp in Visit 2 only (97.26% [3.75-129.16], p=0.0156). There were no significant relationships between relative changes in MEPAmp and sensorimotor function. PAS has potential as an assay of sensorimotor plasticity targeting the LE, however, further investigation is required to support its reliability. Understanding post-stroke LE sensorimotor pathways is necessary for furthering targeted interventions to combat walking deficits.

Rights

Copyright is held by the author. All rights reserved.

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