Stroke is the leading cause of adult disability in the United States, yet there are very few treatments that improve stroke outcome. Obstructive sleep apnea (OSA)--frequent upper airway blockage that occurs during sleep--is common after stroke, affecting more than half of stroke patients. The most common treatment for obstructive sleep apnea in the general population is nasal continuous positive airway pressure (CPAP) applied through a nasal mask during the hours of sleep. Positive air pressure holds the naso-oro-pharyngeal airway open during sleep.