Date on Senior Honors Thesis

5-2026

Document Type

Senior Thesis

Degree Name

B.S.

Department

Psychological and Brain Sciences

Degree Program

College of Arts and Sciences

Committee Chair

Andrea Behrman

Committee Member

Beatrice Ugiliweneza

Committee Member

Jasmine Wang

Author's Keywords

transcutaneous spinal cord stimulation (scTS), spinal cord injury (SCI), pediatric rehabilitation, central pattern generators (CPG), neuromodulation, locomotor recovery

Abstract

Paralysis following spinal cord injury (SCI) has traditionally been considered permanent due to the disruption of supraspinal input to spinal motor circuits. However, growing evidence suggests that spinal networks below the level of injury retain intrinsic motor-generating capabilities through central pattern generators. Transcutaneous spinal cord stimulation (scTS) is a noninvasive neuromodulation technique that delivers electrical stimulation through the skin to reactivate these spinal networks. Although prior studies demonstrate that scTS delivered through research-grade devices is safe and effective in adults and children with chronic SCI, clinical translation remains limited by lack of FDA-approved systems, high costs, and restricted access to proprietary devices. This study examined whether commercially available stimulation devices can produce locomotor-like stepping responses comparable to a research-exclusive reference device in a child with motor-complete SCI. Using a within-subject, double-blinded design, motor-responses elicited by one research-grade stimulator and three commercially available devices were compared across randomized conditions: stimulation without intent to step, stimulation with intent to step, and sham control. Stimulation was delivered using a two-site electrode configuration positioned at T10/11 and L1/2 spinous processes. Primary outcomes included hip and knee joint excursion angles derived from kinematic data. All devices elicited locomotor-like responses during active stimulation relative to sham. Cognitive intent dramatically enhanced motor output – knee excursions increased by 34-75° during intentional conditions. Two commercial devices produced knee excursions exceeding the research-grade reference device. By demonstrating comparable outcomes, these findings aim to inform the clinical implementation of scTS and broaden access to noninvasive neuromodulation in pediatric SCI rehabilitation.

Lay Summary

Paralysis resulting from spinal cord injury (SCI) has long been considered irreversible. However, recent research has shown that regions of the spinal cord below the injury site can still generate movement through specialized nerve circuits called central pattern generators (CPGs). These circuits can stimulate muscles to produce rhythmic movements, such as stepping, even without direct input from the brain. Transcutaneous spinal cord stimulation (scTS) is a noninvasive therapy that delivers mild electrical pulses through electrodes placed on the skin over the spine. This stimulation activates spinal circuits involved in coordinating motor signals and can produce stepping-like activity in the legs. Although previous studies have successfully demonstrated the safety and therapeutic potential of scTS in adults and children with chronic SCI, clinical use remains limited because many stimulation devices are expensive, proprietary, and lack FDA approval.

In this study, we tested whether commercially available stimulation devices could produce stepping-like responses comparable to a research-exclusive scTS device. Children with chronic, complete SCI resulting in paralysis of both legs participated in the study. Each participant underwent assessments to test four stimulation devices, one research-grade device and three marketed alternatives, in a randomized order across three conditions: while distracted (to test involuntary spinal activation), with intent to step (to test whether voluntary effort strengthens response), and sham (fake stimulation used as a control). For each device, two electrodes were placed on the lower back over regions of the spine associated with stepping movements. Additional sensors recorded leg muscle activity and measured hip and knee movements to determine whether coordinated stepping patterns occurred. Participants also rated their comfort and pain levels after each stimulation session.

This research aims to determine whether affordable, widely available devices can safely and effectively deliver scTS therapy in children with SCI. Demonstrating comparable motor responses across devices will help clinicians identify practical stimulation options for clinical use. Ultimately, this research could expand access to motor recovery therapies for children with SCI and support the translation of promising neuromodulation technologies from the laboratory into everyday clinical care.

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