REM Sleep Behavior Disorder

As the name suggests, REM sleep behavior disorder occurs during REM [Rapid Eye Movement] sleep. Patients with this disorder experience episodes of acting out some or all of their dreams. This disorder is more common in middle-aged or elderly men.

The patient may walk, talk, jump, hit, or perform any other action during their dreaming. Most people (the "normal") are partially paralyzed during REM sleep, which prevents them from moving at all. They are unaware of the environment outside of their dream during the disorder's occurrences. When patients have been awakened during REM sleep disorder events, they usually describe dreams involving the same actions they had just made. These episodes do not occur every night, and can range in frequency and severity.

This disorder was first described in 1986. Little is known about this disorder. (1) Clonazebam, or klonopin, a type of benzodiazepine drug, can sometimes prevent these episodes from happening. (1) Other treatment consists of taking careful measures to ensure the safest sleeping environment as possible. Often it is best for the person to sleep alone, so that the bed partner won't be injured. There have been instances in which a sleeper with this or a similar disorder has committed a violent crime while sleeping. (2)

Scientific/technical details: Systems that inhibit movement in Normal REM sleep [See also: Stages of Sleep, this site, for Images]

Basically: "The brain activity during REM, begins in the pons, a structure in the brainstem and neighboring midbrain regions. The pons sends signals to the thalamus and to the cerebral cortex, which is responsible for most thought processes. It also sends signals to turn off motor neurons in the spinal cord, causing a temporary paralysis that prevents movement."(3)

Technically: "In normal REM sleep the pons strongly activates the inhibitory center in the medulla. The midline inhibitory zone in the pons inhibits the lateral locomotor strip. The result is complete paralysis. In REM sleep without paralysis, the lesions break the connections from the pons to the locomotor strip and to the medullary center. In REM sleep the pons is activated, exciting the medullary inbibitory area by projections (tegmento-reticular tract) which connects the pons to the inhibitory center. The medullary center inhibits the motor neurons and gives rise to atonia. A lateral locomotor strip, down the outside of the brain stem, plays an important role in the reduction of motor drive. It is connected to structures in the spinal cord. In REM sleep the pons stimulates the inhibitory zone, turning off the locomotor strip and shutting down motor drive." Dr. Silvia Cardoso, a neuroscientist at a Brazilian university who edits Brain & Mind, an electronic journal on neuroscience, explains that the basis for this REM disorder seems to be a disruption of the brain stem systems that normally mediate REM atonia."(3)

(1) Ancoli-Israel, Sonia. All I Want is a Good Night's Sleep. St. Louis: Mosby, 1996. p. 97

(2)Leoung, Rebecca. "Not Under the Influence: Sleepwalking Rejected as Defense in Murder Case." c. ABC News Internet Ventures. June 25, 1999. URL: http://abcnews.go.com/sections/us/dailynews/sleepwalk990625.shtml

(3) Permission granted for links to her site (and use of images) by Silvia Helena Cardoso, PhD,Center for Biomedical Informatics State University of Campinas, Brazil by email message, Aug. 1999. She is the editor of Brain and mind: electronic magazine on neuroscience. http://www.epub.org.br/cm/n02/mente/neuroestrut_i. htm and http://www.epub.org.br/cm/n02/mente/neurobiologia_i.htm are about the neurobiology of dreams. http://www.epub.org.br/cm/n02/mente/desligamento_i.htm is about REM sleep disorder, and why we don't usually act out dreams.