Longitudinal cognitive dysfunction in patients with obstructive sleep apnea syndrome after transient ischemic attack

To the Editor:Obstructive sleep apnea syndrome(OSAS)is characterized by repetitive episodes of upper airway obstruction(partial or complete)during sleep,which leads to recurrent arterial hypoxemia and sleep fragmentation.Untreated OSAS in middle-aged patients cause impair-ments in attention,vigilance,some aspects of memory,and executive function.[1]Transient ischemic attack(TIA)is characterized by a transient episode of neurological dysfunction caused by focal brain ischemia.By definition,TIA should not bring persistent deficits but it does increase the risk of long-term cognitive impairment.