Executive function in patients with obstructive sleep apnea treated with continuous positive airway pressure

Obstructive sleep apnea (OSA) is characterized by disrupted breathing and hypoxemia during sleep, daytime sleepiness, and changes in cognition and mood. One important question is regarding the reversibility of cognitive deficits after treatment with continuous positive airway pressure (CPAP). Here, we report the outcomes of CPAP treatment as measured by tests of attention and executive function. Thirty-seven individuals with moderate to severe OSA and compliant on CPAP treatment were studied with working memory tasks, neuropsychological testing, and overnight polysomnographic sleep study and compared to 27 healthy controls. CPAP improved the respiratory disturbance index, minimum and mean oxygen saturation (SpO2), subjective sleep quality, and daytime sleepiness ratings compared to pre-treatment values. In terms of current neurocognitive function, treated individuals with OSA performed at a comparable level to controls on basic working memory storage functions but still showed a significant reduction on tests of working memory requiring the central executive. The OSA group also performed worse on neuropsychological measures of complex attention, executive function, and psychomotor speed. While CPAP is an effective treatment for OSA in terms of ameliorating breathing disruption and oxygen desaturation during sleep, as well as daytime sleepiness, some cognitive deficits may be more resistant to treatment.