A complaint of inability to move the trunk or limbs at sleep onset or upon awakening

Presence of brief episodes of partial or complete skeletal muscle paralysis

Episodes can be associated with hypnagogic hallucinations or dream-like mentation (act or use of the brain)

Polysomnography (sleep recording) shows at least one of the following:

  • Suppression of skeletal muscle tone
  • A sleep onset REM period
  • Dissociated REM sleep