Historically, movement disorders have been a puzzle to physicians and psychologists alike. They are defined as “movement disorders that cannot be explained by organic damage to the central nervous system” by the National Institute of Neurological Disorders and Stroke, and the origin of such disorders remain somewhat of a puzzle.
However, a new study is shedding some light on a particular class of movement disorders called synucleinopathies, a subcategory of movement disorders that include Parkinson’s disease and Lewy Bodies, by establishing a link between REM sleep behavior and the onset of such neurodegenerative diseases at least a decade later.
REM sleep behavior is characterized as a disorder wherein dreams are accompanied by excessive body movement.
The research was conducted by the Minnesota Regional Sleep Disorders Center in Minneapolis, and focused on 27 patients who had REM sleep behavior at least 15 years prior to the onset of Parkinson’s and/or Lewy Bodies. Diagnosis of these disorders in the study group came from the Mayo Clinic in Rochester, MN.
Two-thirds of the patients had been diagnosed with either Parkinson’s disease dementia or dementia with Lewy Bodies, while the remaining third were diagnosed with multiple system atrophy, according to Medscape.
The dreams typically associated with REM sleep behavior involve either running away from someone or defending oneself from a predator. Movements associated with these dreams include punching, getting out of bed, and/or shouting. The average age of onset of REM sleep behavior among participants was 49, while the median age for developing one of the neurodegenerative disorders was 72.
The median time between the development of REM sleep behavior and the neurodegenerative disorders was 25 years. In one case, 50 years elapsed between the two diagnoses; typically, the span between the two was about a decade.
What is the significance of the study? According to the researchers, there have been other studies that have shown a link between REM sleep behavior and neurodegenerative disorders. However, these studies did not take long latencies into consideration. The team does concede, however, that more research will need to be conducted to determine whether or not all patients who develop REM sleep behavior will eventually develop a neurodegenerative disorder.
Details of the study are being published in the journal Neurology.