Obstructive sleep apnea syndrome: a cause of acute delirium.

Delirium is a transient global disorder of cognition related to a variety of structural or functional neural disorders. Descriptions and characterizations of delirium associated with obstructive sleep apnea syndrome (OSAS) are rare. We describe a 52-year-old man with severe OSAS associated with sudden onset of delirium and with a fluctuating nighttime course, prolonged for several days. The delirium disappeared after treatment with continuous positive airway pressure (CPAP). The patient remained free of symptoms under CPAP during a follow-up of 8 years.