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Sleep Disorders


Parasomnias are events caused by physical intrusions into sleep which are thought to be triggered by the central nervous system. These dysfunctions do not interfere with actual sleep processes and do not cause insomnia or hypersomnia. They appear more frequently in children than adults.

Arousal disorders appear to be associated with neurological arousal mechanisms. They usually occur early in the night during slow-wave rather than REM sleep and are therefore not the "acting out" of a dream.

Sleepwalking occurs during sleep. The subject may seem wide awake but displays a blank expression, seldom responds when spoken to, is difficult to awaken, moves clumsily, and sometimes bumps into objects, although they will often maneuver effectively around them. Some sleepwalkers perform dangerous activities, like driving a car. Although rarely the case with children, serious injuries can occur. Subjects displaying dangerous tendencies should take precautions like locking windows and doors. Episodes average about ten minutes, seldom occur more than once in any given night, and are seldom remembered.

Night or sleep terrors are sudden partial awakenings during non-REM sleep. Traditionally, a sufferer sits bolt upright in bed in a state of extreme panic, screams loudly, sweats heavily, and displays a rapid heart beat and dilated pupils. The patient will sometimes talk, and might even flee from bed in terror, often running into objects and causing injury. Episodes last about 15 minutes, after which sleep returns easily. There is seldom any recollection of the event. If woken, the subject may display violence and confusion and should, instead, be gently guided back to bed.

Rapid eye movement (REM) sleep parasomnias take place during sleep and include nightmares and the recently discovered REM sleep behavior disorder. This potentially injurious disorder is seen mostly in elderly men and results in aggressive behavior while sound asleep such as punching, kicking, fighting, and leaping from bed in an attempt to act out a dream. Subjects report their dreams, usually of being attacked or chased, become more violent and vivid over the years. Some sufferers even tie themselves into bed to avoid injury. Unfortunately, this disorder was seriously misdiagnosed until recently. It is now readily diagnosable and easily treated.

Sleep-wake transition disorders usually occur during transition from one sleep stage to another, or while falling asleep or waking up. Manifestations include sleeptalking, leg cramps, headbanging, hypnic jerks (sleep starts), and teeth-grinding.

Other parasomnias include excessive snoring, abnormal swallowing, bedwetting, sleep paralysis, and sudden unexplained death during sleep.

Additional topics

Science EncyclopediaScience & Philosophy: Semiotics to SmeltingSleep Disorders - Insomnias And Hypersomnias, Observation And Classification Of Sleep Disorders, Dyssomnias, Parasomnias, Diagnosis Of Sleep Disorders