Rapid eye movement sleep behavior disorder and risk of dementia in Parkinson's disease: a prospective study.
One of the most devastating nonmotor manifestations of PD is dementia. There are few established predictors of dementia in PD. In numerous cross-sectional studies, patients with rapid eye movement (REM) sleep behavior disorder (RBD) have increased cognitive impairment on neuropsychological testing, but no prospective studies have assessed whether RBD can predict Parkinson's dementia. PD patients who were free of dementia were enrolled in a prospective follow-up of a previously published cross-sectional study. All patients had a polysomnogram at baseline. Over a mean 4-year follow-up, the incidence of dementia was assessed in those with or without RBD at baseline using regression analysis, adjusting for age, sex, disease duration, and follow-up duration. Of 61 eligible patients, 45 (74%) were assessed and 42 were included in a full analysis. Twenty-seven patients had baseline RBD, and 15 did not. Four years after the initial evaluation, 48% with RBD developed dementia, compared to 0% of those without (P-adjusted = 0.014). All 13 patients who developed dementia had mild cognitive impairment on baseline examination. Baseline REM sleep atonia loss predicted development of dementia (% tonic REM = 73.2 ± 26.7 with dementia, 40.8 ± 34.5 without; P = 0.029). RBD at baseline also predicted the new development of hallucinations and cognitive fluctuations. In this prospective study, RBD was associated with increased risk of dementia. This indicates that RBD may be a marker of a relatively diffuse, complex subtype of PD.
Department of Neurology, McGill University, Montreal General Hospital, Montreal, Québec, Canada.
Ronald B
RB
Postuma
Josie-Anne
JA
Bertrand
Jacques
J
Montplaisir
Catherine
C
Desjardins
Mélanie
M
Vendette
Silvia
S
Rios Romenets
Michel
M
Panisset
Jean-François
JF
Gagnon
D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D003704:Dementia / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications*; D017286:Polysomnography; D011446:Prospective Studies; D020187:REM Sleep Behavior Disorder / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology; D012306:Risk