TUNE IN: REM SLEEP BEHAVIOR DISORDER: WHAT ARE THE PATHOLOGIC SUBSTRATES WITH A COESXISTING NEUROLOGIC DISORDER? At this year's AAN annual meeting, investigators reported that among the neurodegenerative disorders associated with REM sleep behavior disorder (RBD), 94 percent were synucleinopathies, indicating, experts say, that REM sleep behavior disorder is a highly significant prognostic indicator of future neurodegenerative disease. Autopsy revealed that among those with a coexisting neurologic disorder, Lewy body dementia (LBD) accounted for 46 percent, combined LBD and Alzheimer's disease for 36 percent, multiple system atrophy (MSA) for 12 percent, Alzheimer's disease alone for 3 percent, and progressive supranuclear palsy (PSP) for 1 percent. Previous studies have linked RBD to a greatly increased risk for development of neurodegenerative disease.
The findings “argue that part of the selective vulnerability involved with Lewy body disease and with MSA likely involves REM sleep circuitry,” study leader Bradley Boeve, MD, chair of behavioral neurology at the Mayo Clinic in Rochester, MN, told attendees of the plenary at the AAN annual meeting. He said the hypothesis fits well with the Braak model of Parkinson's disease pathogenesis, in which the disease spreads from lower brain regions to higher ones. “Not all, but many Parkinson's patients have RBD precede their motor features, and this actually fits quite nicely in the Braak model. Now, there still are some controversies and things that don't completely fit, but this is actually making a lot of sense,” he noted, with RBD evolving early, and parkinsonism and cognitive features developing later.
In a video interview, Neurology Today Editor-in-chief Steven P. Ringel, MD, and Associate Editor Robert G. Holloway, MD, discuss the implications of the study and what to tell patients and their families once REM sleep behavior disorder is diagnosed. Read the full Neurology Today article about the study here: http://bit.ly/1bcQYCx. Click the link for the video commentary with Drs. Ringel and Holloway: http://bit.ly/aNQ4KB.