Sleep Parasomnias


Sleep parasomnias refer to disorders of arousal, partial arousal or sleep-wake transition.
Parasomnias are divided into 3 main classes.

Disorders of arousal (from NREM sleep)
Confusional arousals
Sleep terrors

Parasomnias usually associated with REM sleep
Nightmare disorder
REM sleep behavior disorder
Recurrent isolated sleep paralysis

  1. Other parasomnias
  1. Sleep related dissociative disorders
  2. Sleep enuresis
  3. Sleep related groaning (Catathrenia)
  4. Exploding head syndrome
  5. Sleep related hallucinations
  6. Sleep related eating disorder
  7. Parasomnia, Unspecified
  8. Parasomnia due to drug or substance
  9. Parasomnia due to medical condition

The NREM parasomnias typically occur during slow wave sleep (stage 3) but can occur from stage 2 sleep and is due to an incomplete arousal from sleep. It is associated with apparent arousal, mental confusion, (Confusional arousals) to agitation, screaming and autonomic involvement, (Sleep terrors) to getting up and either walking around or performing tasks while still asleep (Sleep walking). They usually occur in the first half of the night but can occur later in the night. Usually occur no more than once a night but have been described in some cases to occur multiple times a night.  In patients with teenage onset of sleepwalking, epilepsy and nocturnal seizures should be considered as differentials.  The typical age for presentation of night terrors is 4-12 years of age, while confusional arousals present at an earlier age.  Also, parasomnias appear to be familial. Most events last between 3-5 minutes and self terminate. Typical of any of the events is a lack of recollection on the part of the offending individual.

Subject or observer noted recurrent mental confusion upon arousal or awakening in the subject
Spontaneous confusional episodes can be induced by forced arousal
An absence of fear, walking behavior or intense hallucinations with events
DPSG showing arousals from SWS
The symptoms are not associated with any other medical condition
The symptoms do not meet the diagnostic criteria for other sleep disorders

The patient has sudden episode of intense terror during sleep
The episodes usually occur in the first third of the night
Partial or total amnesia occurs for the events during the episodes
DPSG showing arousals from SWS. Also tachycardia
Other medical disorders are not the cause
Other sleep disorders are not the cause though they may also exist such as nightmares.

Precipitating factors:
Sleep disordered breathing, sleep apnea, allergic rhinitis, restless sleep and periodic limb movement in sleep.

Evaluation: Complete history and physical examination. Usually does not require an overnight sleep study unless the cases are considered complicated. Videotaping may be helpful.

Management: The key to treatment is accurate diagnosis. If events are rare and do not affect family dynamics treatment is not required. Reassurance is usually sufficient. Treatment should include avoidance of precipitating factors such as sleep deprivation and stress. Parents should be advised not to interfere with the event. Clear room of obstacles or safety hazards. If appropriate add additional locks to doors.
If the events have become disruptive and dangerous to the patient and family and no obvious precipitant is recognized then pharmacological management is an option.

Treatment: First goal of management should be to get sufficient sleep as insufficient sleep can be a trigger for parasomnias.
Address all precipitating factors as any triggers for arousal can predispose to parasomnia events.
Stress reduction and relaxation therapy, hypnosis. When significant psychopathology is  identified then psychotherapy for the patient and possibly family should be considered

Medication: Benzodiazepines are effective for controlling parasomnias but the effectiveness may decrease over time and the events may return once medications are stopped. Tricyclic antidepressants can also be used

Prognosis: Most parasomnias will resolve without intervention but may take longer to clear up. Confusional arousals and night terrors tend to resolve though night terrors may occur even in adults. Sleep walking is more common in adults.

REM parasomnias occur in REM sleep and occur mostly in the second half of the night.
Nightmares: These are REM related events and typically occur in the second half of the night. There is typically a recollection of the nightmare or scary event unlike sleep terrors. The age of onset of nightmares is typically around 3-6 years and can last into adulthood. Certain medications can induce an increase in nightmares as well as a condition in which there is REM rebound with very vivid dreams and nightmares when the medication is withdrawn. Most patients will awaken at termination of the nightmare and can typically remember the events in the morning and recollect the event and its content.

The patient has at least one episode of sudden awakening from sleep with intense fear, anxiety and feeling of impending harm.
The patient has immediate recall of frightening dream content
Full alertness occurs immediately upon awakening with little confusion or disorientation
Associated features include at least one of the following
Return to sleep is delayed and not rapid
The episode occurs in the latter half of the habitual sleep period

Sleep study shows:
Abrupt awakening from at least 10 minutes of REM sleep
Mild tachycardia and tachypnea during the episode
Absence of epileptic activity in association with the disorder
Other sleep disorders, such as sleep terrors and sleep walking can occur.

REM sleep behavioral disorder (RBD):
This is another manifestation of REM related parasomnias in which the patient acts out their dreams. In this condition, the patient appears not to have the typically protective atonia that is seen in REM sleep. This condition is commoner in older individuals and can be seen in patients with Parkingson’s disease. When seen in younger individuals it is associated with an increased likelihood that they will develop Parkingson’s disease in later life. In this condition, the patient may be a risk to themselves and others and it is not uncommon to see spouses injured by the actions of their bed partner.

Predisposing factors for parasomnias:
Genetic factors, insufficient sleep, stress, anxiety and affective disorders. 

Evaluation: Take a good history and physical examination. Obtain a good medication and drug use history. Does not typically require overnight sleep study although in cases of REM it may be helpful in clearly defining the condition. Videotaping of REM behavioral disorder events may also be helpful.

Treatment: Safety is paramount especially in cases of RBD. Maintaining an uncluttered environment is helpful.
Psychotherapy may be necessary in some patients with nightmares
Review of drug management, and consideration of different drug options if such medications are inducing the nightmares
Benzodiazepines can be used to ameliorate the nightmares. Tricyclic antidepressants and Selective serotonin reuptake inhibitors can also be used to reduce nightmares but withdrawal can result can result in REM rebound.