Sleep patterns in Kleine-Levin syndrome.

Diurnal and nocturnal sleep records were obtained from a male and a female with Kleine-Levin syndrome, during excessive daytime sleep attacks and while they were asymptomatic. A common pattern of abnormal sleep was seen in both patients even during the asymptomatic period. The female, aflicted with a severe form of periodic hypersomnia, showed nocturnal and diurnal sleep onset REM periods. The different pattern of sleep abnormality in the female could be an expression of the severity of her symptoms or might indicate a variant of sleep abnormality present only in females with Kleine-Levin syndrome.