neurologic disorders
Idiopathic Hypersomnia
Introduction
Idiopathic hypersomnia is excessive daytime sleepiness with or without a long sleep time; it is differentiated from narcolepsy by lack of cataplexy, hypnagogic hallucinations, and sleep paralysis. (See also Approach to the Patient With a Sleep or Wakefulness Disorder .) Idiopathic hypersomnia is not well-characterized. Cause is presumed to be dysfunction of the central nervous system. Excessive daytime sleepiness is the main symptom; sleep time may or may not be prolonged. 