Acute Intermittent Hypoxia in People Living With Chronic Stroke: A Case Series.

Background: Acute intermittent hypoxia (AIH) is a novel therapeutic intervention that facilitates recovery of function, but the tolerability and effectiveness have not been tested in people living with chronic stroke. The purpose here was to examine whether AIH is tolerable and effective in this population.

Methods: Ten participants with a unilateral, hemispheric stroke were assessed before and after 4 sessions of AIH separated by ≥48 hours in a case series at Shirley Ryan AbilityLab (Chicago). Physician-assessed signs and symptoms (assessed via: repeated symptom reviews, National Institutes of Health Stroke Scale, cranial nerve assessment, a muscle strength test, the Brunnstrom scale, sensory changes, reflexes, assessment of heart and lung status, Fugl-Meyer test, Chedoke-McMaster Stroke Assessment, Modified Ashworth Scale for Spasticity, and Delis Kaplan Executive Function System Color-Word Interference Test) and bilateral upper limb strength (grip and elbow flexion) were assessed before, ≈15 to 30 minutes, and ≈60 minutes after the intervention.

Results: AIH was well-tolerated and there were no adverse events observed. After AIH, grip strength (12.91% and 16.53% improvement at 30 and 60 minutes post-AIH, respectively) and elbow flexion force (5.87% and 7.01% improvement at 30 and 60 minutes post-AIH, respectively) improved in the more-affected limb.

Conclusions: AIH is potentially safe and effective for improving strength in the more-affected limb in people living with hemiparetic stroke. Future work should explore the use of AIH to enhance task-specific training-induced plasticity.

Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT04019522.