People with symptoms suggesting rapid eye movement sleep behavior disorder, or RBD, have twice the risk of developing mild cognitive impairment (MCI) or Parkinson disease within 4 years of diagnosis with the sleep problem, compared with people without the disorder, a Mayo Clinic study has found. The researchers published their findings recently in the Annals of Neurology.
One of the hallmarks of rapid eye movement (REM) sleep is a state of paralysis. In contrast, people with rapid eye movement sleep behavior disorder, appear to act out their dreams when they are in REM sleep. Researchers used the Mayo Sleep Questionnaire to diagnose probable rapid eye movement sleep behavior disorde in people who were otherwise neurologically normal. Approximately 34% of people diagnosed with probable rapid eye movement sleep behavior disorde developed MCI or Parkinson disease within 4 years of entering the study, a rate 2.2 times greater than those with normal rapid eye movement sleep.
"Understanding that certain patients are at greater risk for MCI or Parkinson's disease will allow for early intervention, which is vital in the case of such disorders that destroy brain cells. Although we are still searching for effective treatments, our best chance of success is to identify and treat these disorders early, before cell death," says co-author Brad Boeve MD, a Mayo Clinic neurologist.
Previous studies of Mayo Clinic patients have shown that an estimated 45% of people who suffer from rapid eye movement sleep behavior disorder will develop a neurodegenerative syndrome such as mild cognitive impairment or Parkinson disease within 5 years of diagnosis.
"This study is the first to quantify the risk associated with probable RBD in average people, not clinical patients, and it shows that we can predict the onset of some neurodegenerative disorders simply by asking a few critical questions," says lead author Brendon P Boot MD, a behavioral neurologist. Dr Boot was at Mayo Clinic when the study was conducted. He is now at Harvard University.
Source: News Release
March 13, 2012