Rapid-eye-movement (REM) sleep behavior disorder (RBD) is a sleep disorder that involves abnormal behavior during the phase of sleep characterized by rapid eye movements (i.e., REM sleep).

Rapid-eye-movement (REM) sleep behavior disorder (RBD) is a sleep disorder that involves abnormal behavior during the phase of sleep characterized by rapid eye movements (i.e., REM sleep). Our most vivid dreaming occurs during REM sleep, and in normal sleep, our muscles lose tone in order to keep us from acting out our dreams. However, individuals with RBD lack this normal muscle atonia and exhibit both simple and complex movements during REM sleep. RBD sufferers have a 20% risk of developing Parkinson disease or dementia within 5 years, according to a study published online December 24, 2008 in the journal Neurology .

RBD is a potential marker for the development of Parkinson disease and a type of cognitive disorder called Lewy body dementia. Researchers from McGill University in Montreal, Canada and their colleagues evaluated 93 patients with RBD with an average age of 65 years to determine the long-terms risk of developing Parkinson disease or dementia. During the follow-up period, 26 of the patients developed either Parkinson disease or dementia. A total of 14 patients developed Parkinson disease, 7 developed Lewy body dementia, 4 met the criteria for Alzheimer disease, and 1 developed a disorder called multiple system atrophy. The investigators found that the risk of developing one of these neurodegenerative disorders increased with time to over 50% after 12 years.

This study confirms that RBD is a marker for Parkinson disease and alerts both doctors and RBD patients to be cognizant of warning signs for Parkinson disease so that it can be detected and treated at an early stage.

Source

Neurology. Published online before print December 24, 2008.