Sign Up for a Free Account
  • Updated 10.10.2023
  • Released 10.11.1993
  • Expires For CME 10.10.2026

NonREM parasomnias



Parasomnias are undesirable but not always pathological events. They consist in abnormal behaviors during sleep due to the inappropriate activation of the cognitive process or physiological systems, such as the motor and/or autonomic nervous system. For this reason, parasomnias are conditions constituting a window into brain function during sleep. Non-rapid eye movement (NREM) sleep parasomnias are recurrent abnormal behaviors emerging as incomplete arousals out of NREM sleep. NREM parasomnias are common in the general population, occurring more frequently in children, but they could persist more frequently than expected during adulthood, with a lifetime prevalence of about 7%. When episodes are frequent, NREM parasomnias can result in sleep disruption and injuries with adverse health or psychosocial consequences for the patients, bedpartners, or both. It is, thus, necessary for clinicians to recognize, evaluate, and manage these sleep disorders, especially in adulthood. Many problems hamper a differential diagnosis between non-REM parasomnias and epileptic seizures occurring during sleep. In this article, the authors describe the characteristics of the NREM parasomnias, suggesting the key points for a decisive diagnostic workup.

Key points

• The large number of parasomnias underscores that sleep is not simply a quiescent state but can involve more or less complex behaviors.

• NREM parasomnias are usually benign phenomena, but sometimes and especially in adulthood they could lead to injuries affecting not only the patient but also the bed partner.

• Parasomnias must be distinguished from epileptic seizures arising from sleep.

• Video-polysomnography remains the most useful support for the final diagnosis.

Historical note and terminology

Parasomnias have attracted the interest of writers and scholars for centuries. Their sometimes dramatic manifestations have been described by many. Perhaps the most famous literary examples of parasomnia are the sleepwalking and sleeptalking events by Lady Macbeth in Shakespeare's Macbeth, Moncrieff’s Somnambulist, a play regarding a nighttime walking phantom, and Bellini's La Sonnambula, an innocent girl who suffers from a quirk of nature, hence, eliciting sympathy and compassion. In the novel Tess of the d'Urbervilles Thomas Hardy describes one of the most fascinating and convincing scenes of sleepwalking ever written (54).

This is an article preview.
Start a Free Account
to access the full version.

  • Nearly 3,000 illustrations, including video clips of neurologic disorders.

  • Every article is reviewed by our esteemed Editorial Board for accuracy and currency.

  • Full spectrum of neurology in 1,200 comprehensive articles.

  • Listen to MedLink on the go with Audio versions of each article.

Questions or Comment?

MedLink®, LLC

3525 Del Mar Heights Rd, Ste 304
San Diego, CA 92130-2122

Toll Free (U.S. + Canada): 800-452-2400

US Number: +1-619-640-4660



ISSN: 2831-9125