Acute Intermittent Hypoxia Induces Motor and Cognitive Plasticity in Persons with Relapsing Remitting Multiple Sclerosis

Background: Despite advancements in MS treatment, alleviating existing motor and cognitive deficits remains a challenge. In this study, we evaluated the effect of acute intermittent hypoxia (AIH), a novel therapeutic approach to facilitate functional recovery, in patients with MS. Objective: To test the hypothesis that a single session of AIH enhances spinal motor output and cognitive performance in persons with relapsing remitting MS. Methods: In a randomized, blinded, crossover, placebo-controlled trial, ten individuals with relapsing-remitting MS received AIH (15, 60-second exposures at 9% O2) and sham AIH (21% O2) in a randomized manner, at least one week apart. We assessed changes in isometric ankle strength, lower extremity EMG activity, and cognitive processing speed using the Symbol Digit Modalities Test (SDMT) and California Verbal Learning Test II. Results: Participants showed a significant increase in plantarflexion and dorsiflexion torque at 60 minutes post-AIH (p < .05). Cognitive processing speed (i.e., SDMT scores) had a consistent and significant improvement following AIH (p < .01), but there was no change in auditory/verbal memory. There were no reported adverse events. Conclusion: AIH significantly improved motor and cognitive processing speeds, supporting its utility as a tool for inducing plasticity and complementing MS rehabilitation.