Neuropsychological function in obstructive sleep apnea syndrome (OSAS) compared to chronic obstructive pulmonary disease (COPD).

Forty-nine men, 25 with obstructive sleep apnea syndrome (OSAS) and 24 with chronic obstructive pulmonary disease (COPD), were evaluated with a standard 8-hour nocturnal polysomnogram, multiple sleep latency test the following day and a neuropsychological test battery. The OSAS patients had more respiratory disturbances per hour of sleep, more stage 1 sleep and greater daytime sleepiness than COPD patients. The OSAS patients were as impaired as the COPD patients in neuropsychological test functioning, with the pattern of impairment nonspecific as to hypoxemic-sensitive versus sleepiness-sensitive tasks, with two exceptions. The OSAS patients performed more poorly on a test requiring sustained attention and considered sensitive to sleepiness, whereas the COPD patients performed more poorly on a test requiring motor skills and sensitive to hypoxemia. These deficits in psychomotor and attention appear to be specifically related to patients group (OSAS vs. COPD), but the other deficits found in complex reasoning and memory are nonspecific.