Award Date

Spring 5-14-2021

Degree Type

Doctoral Project

Degree Name

Doctor of Physical Therapy (DPT)

Department

Physical Therapy

Advisor 1

Jing Nong Liang, PT, Ph.D.

First Committee Member

Daniel Young, Ph.D

Second Committee Member

Merrill Landers, Ph.D

Number of Pages

41

Abstract

Background: Stroke can lead to gait abnormalities such as foot drop. Foot drop can result from decreased corticospinal tract input to the ankle dorsiflexors and/or from exaggerated stretch reflexes on the soleus due to reduced reciprocal inhibition from spinal reflex pathways. Transcranial direct current stimulation (tDCS) attempts to modulate corticospinal tract input and spinal reflex pathways by delivering electrical signals to parts of the brain. The degree of neuromodulation from tDCS can be measured through the Hoffman Reflex (H-reflex)—a tool used to estimate alpha motor neuron excitability which is increased in individuals post-stroke. Purpose: The primary purpose of this study was to examine the acute effects of a session of bimodal tDCS combined with upslope treadmill walking on the H-reflex amplitude on people with chronic post-stroke hemiparesis. The secondary purpose of this study was to determine if reduced H-reflex excitability contributes to improved gait and balance function. Methods: Six individuals with chronic post-stroke hemiparesis received two randomly assigned treatment sessions. Each session included upslope treadmill walking paired with either bimodal or sham tDCS. Soleus H-reflex amplitude (H-max/M-max ratio), gait metrics, the Berg Balance Scale (BBS), and the Timed Up and Go (TUG) Test were collected pre- and post-treatment sessions. A 2 x 2 repeated measures ANOVA was used to analyze data. Results: No statistically significant differences in H-reflex amplitude were observed between bimodal tDCS and sham groups. A statistically significant increase in paretic limb stride length was observed following stimulation. In addition, participants in the bimodal tDCS group had a higher BBS score after stimulation compared to the sham group. There were no differences between groups for the other dependent variables. Discussion: Further research on a larger sample size of this patient population is warranted on bimodal tDCS’ ability to regulate H-reflex excitability and improve function.

Keywords

Post-stroke hemiparesis; Walking; Transcranial direct current stimulation; Neuroplasticity; Neuromodulation

Disciplines

Neuroscience and Neurobiology | Physical Therapy

File Format

pdf

File Size

604 KB

Degree Grantor

University of Nevada, Las Vegas

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