The term ‘parasomnia’ which means “around sleep,” is used in reference to a wide range of disruptive sleep related events, including sleepwalking, night terrors, bedwetting, and narcolepsy.


These behaviours and experiences generally occur during sleep and in most cases are infrequent and mild. At times, however, they may occur often enough or become so bothersome that medical attention is required.


The most common of the parasomnias are “disorders of arousal”, which include:


  • confusional arousals
  • sleepwalking (somnambulism), and
  • sleep terrors


Experts believe that the various arousal disorders are related and share some characteristics. Essentially, these occur when a person is in a mixed state, both asleep and awake and often emerging from the deepest stage of non-dreaming sleep. The sleeper is awake enough to act out complex behaviours, but is still asleep and not aware of or able to remember these activities.


Parasomnias are very common in young children and do not usually indicate significant psychiatric or psychological problems.  Such disorders tend to run in families and can be more severe when a child is overly tired, has a fever, or is taking certain medications.  They may occur during periods of stress and may increase or decrease with “good” and “bad” weeks.


Confusional arousals are most common in infants and toddlers, but are also seen in adults. Evidence of confusional arousals includes:


  • crying in bed
  • thrashing around in bed
  • sleeper appearing to be awake
  • once awake, sleeper appears confused and upset
  • resists attempts to comfort or console


It is difficult to awaken a person in the grips of a parasomnia episode.  The confusional arousal can last up to half an hour and usually ends when the agitation subsides and the sleeper awakens briefly, wanting to return to sleep.


This disorder is commonly seen in older children and can range from simply getting out of bed and walking around the bedroom to prolonged and complex actions, such as going to another part of the house or even outdoors. A sleepwalker will sometimes speak, but is unlikely to be clearly understood.


Sometimes complicated behaviours take place during a sleepwalking episode (such as rearranging furniture), but these activities are usually not purposeful. While injuries during sleepwalking are uncommon, sleepwalkers may put themselves in harm’s way – such as walking outside in bedclothes during the winter. Simple precautions enhance safety.


In most cases, no treatment is necessary. The sleepwalker and family can be assured that these events rarely indicate any serious underlying medical or psychiatric problem. In children the number of events tend to decrease with age, although they can occasionally persist into adulthood or even originate during the adult years.


A rare variation of sleepwalking is “sleep-related eating”. This disorder manifests itself as recurrent episodes of eating during sleep, without conscious awareness.


Sleep related eating can occur often enough to result in significant weight gain. Although it can affect both sexes and all ages, it is most common in young women.


These are the most extreme and dramatic of the arousal disorders and the most distressing to witness.


A sleep terror episode often begins with a “blood curdling” scream or shouts and can produce signs that suggest extreme terror, such as dilated pupils, rapid breathing, racing heart, sweating and extreme agitation.


During a sleep terror episode the victim may bolt out of bed and run around the room or even out of the house. In the course of the frenzied event, sleepers can hurt themselves or others.


As disturbing and frightening as these episodes are to an observer, the sleeper usually has no conscious awareness of the event and generally does not remember it upon awakening.


Unlike typical nightmares or bad dreams, sleep terror episodes are not usually associated with vivid dream images that are recalled after awakening.



In typical childhood occurrences of arousal disorders, medical evaluation is not likely to be needed.


You should, however, contact a healthcare professional if a child’s disturbed sleep causes:


  • Potentially dangerous behaviour, such as that which is violent or could cause injury;
  • Extreme disturbance of other household members;
  • Excessive sleepiness during the day.

In these cases formal evaluation and a sleep centre study is warranted.



Because disorders of arousal are relatively uncommon after childhood, adults suffering from these disorders should seek evaluation.


In some cases, these disorders can be triggered by other conditions such as sleep apnoea, heartburn or periodic limb movements during sleep.


A sleep specialist should evaluate the patient’s behaviours and medical history.


Simple precautions should be taken to ensure safety for people with arousal disorders. Clearing the bedroom of obstructions, securing windows, sleeping on the ground floor and installing locks or alarms on windows and doors can add a degree of security for the individual and the family.


In cases severe enough that the sleep disorder leads to injury or involves violence, excessive eating or disturbance to others, treatment may be warranted. Therapy can include medical intervention with prescription drugs or behaviour modification through hypnosis or relaxation/mental imagery.


Hypnagogic hallucinations are episodes of dreaming while awake, usually just before falling asleep. These dreams can be frightening because the setting reflects reality (for example, the bedroom) and the content of the dream is often threatening.


Sleep paralysis is the experience of waking up – usually following a dream – with a feeling that the muscles of the body (except for those used to breathe and move the eyes) are paralyzed. Hypnagogic hallucinations and sleep paralysis may occur together.  They are common in people with narcolepsy, but can also affect others, particularly individuals who are sleep deprived. While they can be terrifying, these events are not physically harmful.


These seizures, which occur only during sleep, can cause the victim to cry, scream, walk or run about, curse or fall out of bed. The victim may behave in a manner similar to a person with an arousal parasomnia. Like other seizures, these are usually treated with medication.


All body muscles – except those used in breathing – are normally paralyzed during REM sleep.


In some people, commonly older men, this paralysis is incomplete or absent, allowing dreams to be “acted out”. Such dream related behaviour can be violent and can result in injury to the victim or bed partner.


In contrast to those who experience sleep terrors, the victim will recall vivid dreams. REM sleep behaviour disorders can be controlled with medication.


Most people have experienced the common “motor” sleep starts – a sudden, often violent jerk of the entire body upon falling asleep. Other forms of sleep start are a sensation of blinding light coming from inside the eyes or head.


An “auditory” sleep start is loud snapping noise that seems to come from inside the head. Such occurrences, while they can be frightening, are harmless.


Grinding of teeth during sleep is very common occurrences and little evidence suggest that teeth grinding is associated with any significant medical or psychological problem.


In severe cases, mouth devices can help reduce the risk of dental injury.


This condition, seen most frequently in young children, can also occur in adults. It takes the form of recurrent head banging, head rolling and body rocking. The individual may also moan or hum.


These activities can occur just before sleep begins or during sleep. Medical or psychological problems are unlikely to be associated with rhythmic movement disorder. Behavioural treatments may be effective in severe cases.


Sleep talking is a normal phenomenon and is of no medical or psychological importance.


Since most of these sleep related behaviours are due to disorders of arousal – which are not medically significant – medical evaluation and treatment is often not necessary.


Medical attention should be considered, however, if the parasomnia behaviours:


  • are violent or cause injury;
  • are disturbing to other household members; or
  • result in excessive daytime sleepiness.


Minor sleep problems can be handled by a primary care professional, often with a consultation with a sleep medicine specialist experienced with these conditions.


Due to the complex nature of some parasomnias, however, proper diagnosis requires expert clinical evaluation and sleep laboratory monitoring of many body functions during sleep.


These evaluations should be directed to a sleep specialist with experience in such cases.


In most cases of bothersome Parasomnias, a specific case can be identified and effectively treated.

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