Predictors of Conversion to Neurodegenerative Disease in REM Sleep Behavior Disorder

Close up of nose with spider veins
Close up of nose with spider veins
Several prodromal symptoms in REM sleep behavior disorder are highly associated with conversion to neurodegenerative diseases.
The following article is part of conference coverage from the 2018 American Academy of Neurology Annual Meeting in Los Angeles, California. Neurology Advisor’s staff will be reporting breaking news associated with research conducted by leading experts in neurology. Check back for the latest news from AAN 2018.

LOS ANGELES – Several prodromal markers among patients with REM sleep behavior disorder (RBD) convey a significant risk for conversion to neurodegenerative diseases including Parkinson disease, dementia with Lewy bodies, and multiple system atrophy, according to data from a multicenter study presented at the 2018 American Academy of Neurology Annual Meeting, April 21-27 in Los Angeles.

A team of investigators led by Ronald Postuma, MD, MSc, of Montreal General Hospital in Quebec, Canada, analyzed prospective follow-up data from 21 centers included in the International RBD Study Group. Each study center assessed patients with confirmed RBD (without neurodegenerative disease) with sleep, motor, cognitive, autonomic, and special sensory tests at baseline. Mean age of participants was 68.1 years; 82% were men, and mean follow-up was 4.1 years. The investigators used Kaplan-Meier analysis to assess risk for dementia and parkinsonian conversion, and Cox proportional analysis to assess predictors of conversion.

Analysis revealed a conversion rate to dementia/parkinsonian disorders of 12% to 18% at 3 years, 24% to 36% at 5 years, and 51% to 63% at 10 years. Risk for disease conversion was significantly associated with abnormal olfaction (hazard ratio [HR] 2.6; P <.001), motor symptoms (HR 2.6; P <.001), subtle motor signs (HR 2.0; P <.001), abnormal quantitative motor testing (HR 3.5; P <.001), constipation (HR 1.6; P =.003), increased REM tone (HR 1.6; P =.04), and abnormal dopamine transporter (DaT) scan (HR 3.2; P <.001). Notably, abnormal cognition and color vision were associated with conversion to primary dementia (HR 11.2; P <.001 and HR 3.6; P <.002) but not primary parkinsonism.

No predictive value was observed for the following symptoms: somnolence, insomnia, urinary dysfunction, erectile dysfunction, decrease in systolic blood pressure, depression, anxiety, or substantia nigra ultrasound findings.

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The findings confirm that patients with idiopathic RBD have a high rate of conversion to neurodegenerative diseases, which “provides an unprecedented opportunity to directly observe prodromal neurodegenerative states and to intervene with neuroprotective therapy,” the investigators wrote. They hope that the findings will help to stratify patients for inclusion in neuroprotective clinical trials.

Disclosures: The study was supported by the Canadian Institute of Health Research, Fonds de la Recherche Sante Quebec. Several study authors report disclosures. Please see the abstract for a full list.

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Postuma R, Iranzo A, Hu M, et al. Predictors of neurodegeneration in idiopathic REM sleep behavior disorder: a multicenter cohort study. Presented at: 2018 American Academy of Neurology Annual Meeting. April 21-27, 2018; Los Angeles, CA. CCI.003.