Parasomnias include disorders with undesirable behaviors or experiences that occur during sleep or during partial arousals from sleep.

Disorders of Arousal

The following three sleep disorders are overlapping types of parasomnia that are often grouped together as “disorders of arousal." They occur during states of partial arousal out of deep, non-REM sleep, usually in the first third of the night. While experiencing episodes, people are typically disoriented and non-responsive, and they typically don't remember the episode.

  • Confusional Arousals - Confusional arousals include states of mental confusion or confused behavior during partial arousals from sleep, usually in the first third of the night but sometimes upon awakening in the morning. They are most common in children up to age five. The person may resist direction or even lash out violently if interfered with.
  • Sleepwalking or Somnambulism - Sleepwalking or somnambulism are partial arousals from sleep that include walking around in a state of limited consciousness, which may include diminished awareness of the environment, reduced responsiveness and impaired judgment. Behaviors may be inappropriate, nonsensical or at times dangerous. Sleepwalking is most common in children ages 8 to 12 but can persist into adulthood.
  • Sleep Terrors or Night Terrors - These are sudden partial arousals from sleep with intense fright or terror, often beginning with a scream, frequently with increased heart and respiratory rate, confusion and non-responsiveness, at times with vigorous “fight or flight” behavior that can be dangerous. If mental content is present, it is usually simple and fragmentary (for example, an image of a threatening presence). Often, individuals cannot remember these episodes.


Confusional arousals, sleepwalking and sleep terrors may be triggered by other sleep disorders such as obstructive sleep apnea (OSA). Treatment will first address any underlying sleep disorder. Sleep patterns should be consistent and allow for sufficient sleep. Sleep deprivation and alcohol consumption may bring out or increase these disorders. It may be necessary to take safety measures to ensure that people with a disorder of carousel does not harm themselves or others. If dangerous or disruptive behaviors persist, medications may be helpful in controlling the disorder.

Other Parasomnial Sleep Disorders


REM Sleep Behavior Disorder (RBD)

This is a disorder in which dreams are acted out due to a loss of the muscle paralysis that usually prevents people from enacting their dreams during REM sleep. The dreams that are acted out may be violent and can lead to injury to the dreamer and/or the bed partner. RBD may occur in conjunction with, or as a predecessor to, certain neurological disorders such as Parkinson’s Disease. Sometimes, it can result from medication usage. RBD can usually be controlled with the use of appropriate medications.


Nightmares are very disturbing dreams that result in repeated awakenings from sleep. Most often they are dreams that are very frightening but also at times may be dreams with anger, sadness, disgust and other unpleasant emotions. The person usually becomes alert quickly when they awaken and has detailed recall of an elaborate dream. Nightmares most often occur out of REM sleep. Repetitive nightmares often occur as a symptom of Post-Traumatic Stress Disorder (PTSD), where they may include a partial replay of a traumatic event. Nightmares typically reflect psychological stress and conflict. If nightmares are persistent and cause significant distress, treatments such as medications, cognitive-behavioral therapy and psychotherapy may be used.

Sleep Paralysis (Recurrent, Isolated Form)

While sleep paralysis may occur as a feature of the sleep disorder called narcolepsy, it also occurs as an isolated symptom. A person experiences an inability to move or speak, either at the onset of sleep or upon awakening from sleep. The episodes may last from seconds to several minutes. Dreamlike experiences may accompany the paralysis. In sleep paralysis, the muscle paralysis that normally occurs during REM sleep spills over into the onset of sleep, or into the immediate period of awakening from sleep. If the person does not understand what is happening, the sleep paralysis may be intensely frightening. Explanations and reassurance may be very helpful.

Sleep-related Eating Disorder

A sleep-related eating disorder includes repeated episodes of eating arising out of sleep, usually in a state of partial awareness and partial sleep, or with nearly full awareness. But sometimes there is virtually no awareness at all, similar to classic sleepwalking. The person may consume odd or even dangerous items. Complications often include weight gain and disrupted sleep with associated daytime fatigue. Medications may be helpful in controlling the symptoms.

Sleep Talking

Sleep talking is not regarded as a sleep disorder. Talking can occur during any stage of sleep and may be more or less understandable. It is often a normal phenomenon, though it may occur as part of the larger picture in parasomnias such as REM Sleep Behavior Disorder, sleepwalking or sleep-related eating.

Rhythmic Movement Disorder

Rhythmic movement disorder is characterized by repetitive, stereotyped, rhythmic movements involving large muscle groups, such as body rocking, head banging and head rolling, that occur around bedtime, at sleep onset or during sleep. These phenomena are common among infants and children and are only considered a disorder if they have serious consequences, such as significant sleep disruption, impairment of daytime functioning or bodily injury to the child. Rhythmic movements typically begin in the first year of life and usually, but not always, spontaneously resolve by age 5.

Diagnoses for Parasomnias

There are almost 100 sleep disorders, and the University of Michigan Sleep Disorders Center has experience in evaluating and treating all of them. Diagnosis of a parasomnia disorder will depend upon the symptoms and may include a sleep study.

Next Steps

Please call 734-936-9068 to schedule a clinic visit.

We will need a referral from your physician before your appointment. We look forward to helping you resolve your sleep issues.