SPECTRAL-ANALYSIS OF WAKEFULNESS AND REM-SLEEP EEG IN PATIENTS WITH SLEEP-APNEA SYNDROME

Neuropsychological investigations of patients with obstructive sleep a pnoea syndrome (OSAS) have shown impairments in such basic functions a s memory, attention and executive control. Since executive functions a re known to be dependent on the integrity of the frontal lobe, it was hypothesized that OSAS may be associated with hypoxaemic frontal lobe dysfunction, To test this hypothesis, 21 apnoeic patients and 10 norma l controls mere studied with quantitative electroencephalographic (EEG ) methods during rapid eye movement (REM) sleep, when most apnoeic eve nts occur and during wakefulness. In apnoeic patients, EEG slowing in REM sleep was observed over frontal, central and parietal regions, whi le EEG slowing during wakefulness was observed over all cortical regio ns examined. A positive correlation was found between EEG slowing duri ng wakefulness and oxygen desaturation during the night, Contrary. to the hypothesis, these electroencephalographic changes mere not localiz ed only. to the frontal region. This result may explain the wide range of neuropsychological deficits noted in patients with obstructive sle ep apnoea syndrome, in addition to their poor performance in tasks of executive functioning.