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Blog Feature

By: AAST Associate Editor on September 17th, 2020

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Sleep Disorders | Parasomnias

This blog is based off of the AAST 2019 Annual Meeting Session "Parasomnias." For more information on this session and other session recordings click here.

From nightmares to sleepwalking to REM sleep behavior disorder (RBD), parasomnias can occur in many forms without the patient even knowing they are experiencing an event. For sleep professionals, it is imperative they can educate patients with parasomnias as these sleep disorders can have lasting and physically damaging effects.

What Are Parasomnias?

Parasomnias are a group of sleep disorders that involve unwanted physical events or experiences that occur while one is falling asleep, sleeping or waking up from sleep. They can cause abnormal movements, behaviors, emotions, perceptions and dreams, and can cause physical injuries, psychological disturbances, disrupted sleep and adverse health effects. Those who experience parasomnias remain asleep during the event and often have no recollection that it occurred.  

NREM parasomnias include:

  • Sleep terrors
  • Confusional arousals
  • Sleepwalking
  • Sleep related eating disorder

REM-Related parasomnias include:

  • Nightmares
  • Rapid eye movement (REM) sleep behavior disorder
  • Recurrent isolated sleep paralysis

Other parasomnias include:

  • Sleep enuresis (Bedwetting)
  • Sleep related hallucinations
  • Exploding head syndrome

Difference Between Parasomnias and Common Arousal/Awakening

As noted on the Stanford Health Care webpage on confusional arousals, arousals are usually brief periods of time “when a sleeping person appears to wake up but their behavior is unusual or strange.” There is usually little to no recollection of any events that may have occurred while in this state.

Understanding Parasomnias

Mentioned in the 2019 AAST Annual Course presentation “Parasomnias,” there are two essential concepts that must be understood for parasomnias.

  1. Sleep and wake are not necessarily mutually exclusive.
  2. The components of sleep and wakefulness may dissociate or oscillate rapidly — there is an overlap that occurs between wake and REM and wake and non-REM.

The Overlapping of Sleep Stages

As we transition from one stage or state (i.e., wake, REM, NREM) to another, the discrete borders of sleep stages and wake may overlap and become fuzzy. The overlapping of sleep states is associated with various parasomnias.

  • Overlap of wake and NREM = NREM parasomnias

Parasomnias attributed: sleep terrors, confusional arousals, somnambulism, enuresis, sleep eating and drinking disorder, sexsomnia

  • Overlap of wake and REM = REM parasomnias

Parasomnias attributed: cataplexy, hypnagogic/hyponopomic hallucinations, sleep paralysis, REM Behavior Disorder (RBD), nightmare disorder

  • Overlap of NREM and REM = little consequence as we stay asleep
  • Overlap of all three stages of sleep = status dissociates

Simultaneous appearance or rapid oscillation of all states

REM Sleep Behavior Disorder (RBD)

According to the Mayo Clinic overview of REM sleep behavior disorder, rapid eye movement (REM) sleep behavior disorder is defined as a sleep disorder where vivid, and often unpleasant, dreams are physically acted out with vocalization and sudden movements occurring during REM sleep. This disorder appears gradually and can worsen over time as well as be associated with other neurological conditions such as Lewy body dementia, Parkinson’s disease or multiple system atrophy.

Common risk factors for RBD include:

  • Being a male aged 50 and older
  • Having a neurodegenerative disorder
  • Having narcolepsy
  • Taking medications such as some newer antidepressants

REM Parasomnia Treatments

While therapeutic options haven’t been well studied, the following are some options that have been helpful:

  • Education on sleep stages and normal REM sleep paralysis
  • Reassurance that many REM parasomnias are common and seldom serious
  • Sleep hygiene improvements
  • Cognitive behavioral therapy
  • Medications such as clonazepam or melatonin
  • Antidepressants
  • Meditation-relaxation therapy prior to bed
  • Image rehearsal therapy

NREM Parasomnias

As noted by the National Sleep Foundation, non-rapid eye movement (NREM) parasomnias occur when the brain is partially in non-REM sleep and partially awake enough to carry out activities without being consciously aware of them. NREM sleep arousals usually occur during slow wave sleep (SWS) and therefore these parasomnias usually occur during the first half of the night sleep, versus REM sleep parasomnias, which usually occur later in the night.

NREM parasomnias include:

  • Sleep terrors
  • Confessional arousals
  • Somnambulism (sleep walking)
  • Sleep related eating disorder
  • Sexsomnia

Sleep terrors, confusional arousals, somnambulism and enuresis often occur in children and often times children will outgrow these parasomnias as they grow older.

NREM Parasomnia Treatments

There is no consensus on how to treat NREM parasomnias. Depending on the severity of the parasomnia, the following may be recommended:

Mild cases

  • Reassurance and education
  • Minimal intervention during the event
  • “Parasomnia proof” the environment
  • Practice of good sleep hygiene
  • Brief naps during the day
  • Fluid limitation in the evening

Moderate cases

  • CBT
  • Hypnosis/psychotherapy

Severe Cases

Pharmaceutical intervention in addition to all of the above mentioned

AAST 2019 Annual Meeting Recordings Bundle


Earn up to 12.5 CECs with the 2019 Annual Meeting Recordings Bundle. Recordings are sold as a bundle or individually. Purchase your access here.