Safety and feasibility of transcranial direct current stimulation in amyotrophic lateral sclerosis – a pilot study with a single subject experimental design

Introduction: Transcranial direct current stimulation (tDCS) has been explored as a neuromodulatory tool to prime motor function in several neurological disorders. Studies using tDCS in amyotrophic lateral sclerosis (ALS) are limited. We investigated the safety, feasibility and effects of long-term tDCS in an individual with ALS. Methods: A 36-year-old male diagnosed with clinically definite ALS received 12 sessions each of anodal, sham, and cathodal tDCS. Outcome measures included disease progression (revised ALS functional rating scale (ALSFRS-R)), clinical measures of endurance and mobility, and corticomotor excitability. Results: No adverse events or change in disease progression were noticed during the study. Small improvement in gait speed (15% increase) was noticed with anodal tDCS only. Conclusions: This case study demonstrates the safety and feasibility of long-term facilitatory and inhibitory tDCS on a single participant with ALS. This study serves as a guideline for implementing tDCS in future ALS trials.