Résumé
Central hypersomnolence disorders correspond to numerous etiologies of patients with a complaint of excessive daytime sleepiness, excessive quantity of sleep (i.e., hypersomnia), or sleep inertia (i.e., alteration in vigilance following waking up). Hypersomnolence significantly interferes with several aspects of life, including negative social and professional impacts. Several steps of evaluation of these patients are required to explore sleep, sleepiness, and hypersomnia; to quantify the severity of the condition; and to achieve a diagnosis of central hypersomnolence disorder. Hence, clinical interviews, questionnaires, sleep diaries, polysomnography, the Multiple Sleep Latency Test, the Maintenance of Wakefulness Test, continuous 24-hour polysomnography recording, and additional tests in particular circumstances (measurement of hypocretin-1 in cerebrospinal fluid, HLA DQB1*06:02 genotyping, and brain magnetic resonance imaging) allow the definitive diagnosis of central hypersomnolence disorders. This chapter details the clinical signs, laboratory investigations, pathophysiology, management, and some perspectives on most etiologies of central hypersomnolence disorder as reported in the revised International Classification of Sleep Disorders, third edition: narcolepsy Type I and Type II; idiopathic hypersomnia; Kleine-Levin syndrome; insufficient sleep syndrome; and hypersomnia due to a medical disorder, due to a medication or substance, or associated with a psychiatric disorder.