A Large Survey of Kleine-Levin Syndrome

The largest study to date provides insights into the prevalence of numerous symptoms of this poorly understood syndrome.

Kleine-Levin syndrome (KLS) is a disorder of recurring hypersomnolent stupor. This international cross-sectional survey contains more cases than all previous reports aggregated. Most cases were identified through a list from the KLS Foundation. The 108 patients fulfilled the International Classification of Sleep Disorders II criteria and completed a questionnaire of the authors’ devising.

The results largely confirmed previous descriptions. Adolescent boys predominated over girls 3:1; mean age of onset was 15.7 years. Individuals of Ashkenazic Jewish origin were disproportionately represented for the populations surveyed. Of the 108 participants, 89% recalled a precipitating event, usually an infection. During episodes, sleep persisted for a…

Reviewing Author

Allan H. Ropper, MD