Parasomnias and other sleep-related movement disorders

Parasomnias are undesirable physical phenomena that occur predominantly or exclusively during the sleep period. They are not principally abnormalities of the processes responsible for the states of sleep and wakefulness, and manifest as activation of skeletal muscle or the autonomic nervous system during sleep. They usually occur intermittently or episodically and may give rise to violent and potentially injurious behavior. Parasomnias have been classified as either disorders of arousal or disorders that are usually associated with rapid eye movement (REM) sleep.