IDIOPATHIC HYPERSOMNIA

Identification of idiopathic hypersomnia dates back 20 years only. It typically consists of prolonged nocturnal sleep, great difficulty waki ng up in the morning or at the end of a nap, and constant or recurrent excessive daytime sleepiness. Complete and incomplete forms are encou ntered. Twenty-three subjects fulfilling ICSD criteria are reported wi th clinical, polysomnographic and immunogenetic data. Considering diff erential diagnosis is an important step in the diagnosis of idiopathic hypersomnia. Idiopathic hypersomnia is much less frequent than narcol epsy. A strong genetic component is suggested by the high proportion o f familial cases. No association with HLA has been evidenced to date.