Sleep disorder a precursor of brain-degenerating diseases

Mayo Clinic sleep medicine specialists have found that almost two-thirds of patients with REM sleep behavior disorder (RBD) develop degenerative brain diseases by approximately 11 years after diagnosis of RBD. Findings will be presented June 19 at the Associated Professional Sleep Societies’ SLEEP 2006 meeting in Salt Lake City.

“This study found RBD most frequently led to neurodegenerative diseases called the synucleinopathies: Parkinson’s disease or dementia with Lewy bodies,” says Maja Tippmann-Peikert, M.D., Mayo Clinic sleep medicine specialist, neurologist and the study’s lead researcher. “From our findings, I would consider those with RBD at increased risk for these diseases.”

RBD is a sleep disorder in which patients act out their dreams, which are often unpleasant and violent, according to Dr. Tippmann-Peikert. This acting out results from a loss of normal muscle paralysis in REM (rapid eye movement) sleep, the dream stage, which ordinarily prevents enacting one’s dreams.

“The danger with RBD is that patients can hurt themselves or their spouses during the acting out behaviors — bruises, lacerations, bone fractures and even subdural hematomas (brain hemorrhages) have been reported,” says Dr. Tippmann-Peikert.

In this study, the investigators mailed questionnaires to 39 patients diagnosed with RBD at the Mayo Clinic Sleep Disorders Center between 1988 and 1995. If a patient had died, the questionnaire was mailed to surviving relatives. Of the 23 patients who agreed to participate, five had developed dementia or Parkinson’s disease, and 10 reported neurological symptoms highly suggestive of dementia or Parkinson’s disease. The patients in this study were an average of 11.2 years beyond their diagnoses of RBD.

This study is the second long-term follow-up study following patients with idiopathic, or inexplicable, RBD, confirming previous findings by Carlos Schenck, M.D., and Mark Mahowald, M.D., of Minnesota Regional Sleep Disorders Center at Hennepin County Medical Center in Minneapolis.

Other studies are under way to determine whether RBD is a state of pre-Parkinson’s, pre-dementia or pre-multiple system atrophy (another type of synucleinopathy), according to the Mayo Clinic researchers.

Researchers have reported that as the brain-degenerating disease progresses, RBD may decrease in frequency and intensity or resolve completely, says Dr. Tippmann-Peikert.

There is no intervention to prevent those with RBD from progressing to Parkinson’s disease, dementia or multiple system atrophy, says Dr. Tippmann-Peikert, as the origin of RBD is not clear enough to develop an appropriate therapy. Even though no preventive treatment exists yet, she says RBD patients can:

* Use safety precautions in their bedrooms to prevent injury (e.g., move nightstands away from the bed, use extra pillows or pillows on the floor next to the bed for extra padding, remove dangerous objects such as weapons from the bedroom, lock all windows and doors to walk-out decks)
* See a sleep specialist and, if prescribed, take medications to suppress RBD symptoms
* Become familiar with the signs and symptoms of Parkinson’s disease, dementia or multiple system atrophy
* Follow up regularly with a sleep specialist to monitor for signs of brain-degenerating illnesses, and consider a referral to a neurologist if any signs appear

Dr. Tippmann-Peikert also stresses the importance of diagnosing RBD as early as possible.

“Awareness of excessive nocturnal behaviors and dream enactment and bringing it to the attention of a physician could lead to an early diagnosis of Parkinson’s disease, dementia or multiple system atrophy,” she says. “Hopefully, early identification of patients with idiopathic RBD will lead to close monitoring and early treatment of any developing neurological disorders.”

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