ABSTRACT
In 1925, Kleine was the first to report on a case series of 9 patients with recurrent (periodic) hypersomnia (two with increased food intake) and to propose the existence of a novel disease entity (1). Less known is the fact his case series included a young woman with menstruation-linked hypersomnia, a syndrome now considered as a distinct type of recurrent hypersomnia (2). Previous single reports with periodic hypersomnia had been published before, most notably a case by Brierre De Boismont in 1862:
Levin emphasized the association of periodic somnolence with morbid hunger (a symptom subsequently called megaphagia) using a single personal case and previously published reports (4). Critchley proposed the eponym Kleine-Levin syndrome (KLS) and suggested diagnostic criteria based on 26 published patients: male gender, onset in adolescence, periodic hypersomnia, compulsion to eat, and spontaneous remission (5,6).
