POSTED: Wednesday, June 27, 2012 - 8:00pm
UPDATED: Wednesday, June 27, 2012 - 8:14pm
CNN — If someone you know kicks and punches you while they are sleeping, it may be because they have something called REM sleep behavior disorder or RBD, an extremely rare sleep disorder that affects an estimated 0.5% of adults worldwide.
Now researchers say they have identified some of the risk factors that contribute to someone getting RBD, which they believe can be a precursor to neurodegenerative diseases like Parkinson's. Over half of people with RBD develop a neurodegenerative disease, according to the American Academy of Neurology.
When people without this disorder are in REM sleep (the short period of time when you actually dream), their muscles are usually in a state of paralysis (atonia), according to the Cleveland Clinic. But people with RBD move their body or limbs while dreaming. and they could be acting out what they are dreaming. People with RBD are in danger of harming sleep partners as they act out.
The new study, published Wednesday in the journal Neurology, identifies environmental risk factors for RBD, which include smoking, head injury, pesticide exposure, low education and farming.
What's unique about the study is that it included data from 13 institutions in 10 countries, and included 347 cases of REM sleep behavior disorder and 347 control subjects matched by age and sex. That makes it the largest study of RBD to date.
"Until now, we didn't know much about the risk factors for this disorder, except that it was more common in men and in older people," explained study author Dr. Ronald B. Postuma of McGill University Health Centre in Montreal, in a statement. "We wanted to investigate whether the risk factors for REM sleep behavior disorder were similar to those for Parkinson's disease or dementia."
"One of the most intriguing aspects of this work is the picture of similarities and differences among risk factors for RBD and Parkinson disease," wrote Stanford University neurologists Drs. Shannon Sullivan and Christian Guilleminault and Dr. Carlos Schenck, a psychiatrist at the University of Minnesota, all authors of an editorial published in Neurology. "While pesticide exposure appears to be a risk factor for both disorders, smoking, for example, which is protective for PD, is a risk factor for RBD."
The study authors suggest their findings open up new areas for research for RBD.
Sleep disorders and disturbances affect millions of Americans. The National Institutes of Health estimates that 25% to 30% of adults, teens and children are affected by sleep disorders which have been proven to contribute to disability, illness and even death.