Kleine-Levin syndrome: a review.

Kleine-Levin syndrome is a recurrent hypersomnia associated with symptoms of hyperphagia, hypersexuality, and cognitive impairment. This article reviews the current available research and describes common clinical symptoms, differential diagnosis, and acceptable workup and treatment. Although deficits have traditionally been thought to resolve between episodes, functional imaging studies and long-term neuropsychological testing in select patients have recently challenged this notion. This may suggest that Kleine-Levin syndrome is not as benign as previously considered.