Document Type

Article

Domestic/International

Domestic

Location

Chicago, Illinois, USA

Publication Date

2026

Abstract

Introduction: Amyotrophic Lateral Sclerosis (ALS) is a progressive neurodegenerative disease with no known cure. Upper motor neuron and lower motor neuron (LMN) degeneration occurs which results in loss of motor control. Nerve Conduction Studies (NCS) provide critical insight into lower motor neuron dysfunction by measuring spinal motor neuron excitability. This study determined changes in neurophysiological measures via NCS after 6 months of remotely supervised transcranial direct current stimulation (tele-tDCS) in individuals with spinal-onset ALS.

Methods: 2 participants (1 female age 55; 1 male age 53) with ALSFRS-R (clinical measure of ALS progression) scores ≥2 for swallowing and ≥1 for walking received 72 tele-tDCS sessions over 24 weeks. Participants of this case series were derived from a larger randomized clinical trial that used ALSFRS-R scores to evaluate efficacy of tele-tDCS intervention. NCS data were collected at pretesting, two mid-testing visits, post-testing, and a 3-month follow-up. In each testing session M wave and F wave data was collected. Participants received 20 supramaximal stimulations to collect F wave data calibrated to individual thresholds based on their M wave response. Measures of peripheral nervous system health, Neurophysiological Index (NI) and F/M amplitude ratios, were analyzed to evaluate LMN integrity.

Results: The greatest improvements in NI were seen after 12 weeks and neurophysiological measures of ALS progression were not associated with ALSFRS-R scores.

Conclusion: Findings suggest that more research with greater sample sizes is needed to establish a causational relationship between tele-tDCS and the LMN outcomes, determine the reliability of trends seen in this study that may indicate discrepancies in neurophysiological measures of ALS compared to ALSFRS-R scores, and to postulate mechanisms of reinnervation occurring in tele-tDCS.

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The views expressed in this paper are solely those of the author.