Auditory event-related potentials before and after treatment with nasal continuous positive airway pressure in sleep apnea syndrome

Auditory event-related potentials (ERP), multiple sleep latency tests, mini-mental state exam, and depression tests were studied in 15 patients with obstructive sleep apnea syndrome (OSA). The P3 wave latency of ERP was significantly increased compared with 15 age-matched control subjects. After 4 weeks and after 1 year of treatment of OSA by nasal continuous positive airway pressure (CPAP), there was no significant improvement in the abnormalities of ERP. These observed changes in ERP were not correlated with excessive daytime sleepiness, depression, nocturnal hypoxemia, and sleep fragmentation. The cause of increased P3 latency has not been elucidated, but a chronic cerebral insult was suspected.