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Disorders That Disrupt Sleep (Parasomnias)

Disorders That Disrupt Sleep (Parasomnias) Overview

Parasomnias are disruptive sleep-related disorders. They are characterized by undesirable physical or verbal behaviors or experiences. Parasomnias occur in association with sleep, specific stages of sleep (see Sleep: Understanding the Basics), or sleep-awake transition phases.  

Parasomnias may be divided into the following categories:

  • Primary parasomnias are the disorders of sleep states. They are further classified according to the stage of sleep in which they originate: rapid eye movement (REM) (a stage of sleep in which the eyes move rapidly and dreaming occurs) or non-rapid eye movement (NREM) (stage of sleep in which eye movement does not take place. For details of stages of sleep, see Sleep: Understanding the Basics).

  • Secondary parasomnias are disorders of other organ systems that may manifest during sleep, for example, seizures (convulsions), respiratory dyskinesias (difficulty in performing respiratory movements), arrhythmias (abnormal heart rhythms), and gastroesophageal reflux (food or liquid regurgitating from the stomach into the foodpipe).

The 5 disorders that are discussed in this article are nightmare disorder, sleep terror disorder, sleepwalking disorder (somnambulism), REM sleep behavior disorder, restless legs syndrome (RLS), and periodic limb movement disorder (PLMD).

Nightmare disorder   

Nightmare disorder is also called dream anxiety attack. Most patients with nightmare disorder are children. Nightmares are frightening dreams that occur during REM sleep and are associated with an increase in heart rate (tachycardia), an increase in the rate of breathing (tachypnea), profuse sweating, and arousal. Most of the time, the patient remembers the scary dream in detail and responds to soothing and comforting by a parent or caregiver.  

Sleep terror disorder   

Sleep terror disorder is characterized by extreme panic and a sudden, loud, terrified scream during sleep, followed by physical activities such as hitting objects or moving in and out of the bedroom. Persons with this disorder can injure themselves. Sleep terror is a disorder of arousal that primarily occurs during stages III and IV of NREM sleep. Subsequent recollection of the episodes either does not occur or is partial.

Sleepwalking disorder

Patients with sleepwalking disorder show complex automatic behaviors, such as wandering aimlessly, carrying objects without any purpose, going outdoors, and performing other activities of varying complexity and duration (even driving). Persons affected with the disorder usually have their eyes wide open in a stare. They may mumble; however, communication with a person who is sleepwalking is usually poor or impossible. This disorder occurs in the slow-wave stages of NREM sleep.

REM sleep behavior disorder

Patients with REM sleep behavior disorder act out distinctly altered dreams that are vivid, intense, action-packed, and violent. Dream-enacting behaviors include talking, yelling, punching, kicking, sitting, jumping out of bed, arm flailing, and grabbing. An acute form may occur during withdrawal from ethanol or sedative-hypnotic drugs. See REM Sleep Behavior Disorder.  

Restless legs syndrome and periodic limb movement disorder 

Restless legs syndrome and periodic limb movement disorder are common disorders that often may coexist. The primary symptom of restless legs syndrome is insomnia (inability to sleep), whereas periodic leg movement disorder is a well-recognized cause of excessive daytime sleepiness. Nearly all persons with restless legs syndrome have periodic limb movements, and only few persons with periodic limb movement disorder also have restless legs syndrome.

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Parasomnias »

Parasomnias are disorders characterized by undesirable motor, verbal, or experiential phenomenon occurring in association with sleep, specific stages of sleep, or sleep-awake transition phases.

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