title: REM sleep behavior disorder predicts cognitive impairment in Parkinson disease without dementia.
abstract: OBJECTIVE
  To assess the relationship between the presence of REM sleep behavior disorder (RBD) and the cognitive profile of nondemented patients with Parkinson disease (PD).
  
  
  BACKGROUND
  Cognitive impairment is an important nonmotor symptom in PD. Waking EEG slowing in nondemented PD has been related to the presence of RBD, a parasomnia affecting brainstem structures and frequently reported in PD. For this reason, RBD may be associated with cognitive impairment in PD.
  
  
  METHODS
  Thirty-four patients with PD (18 patients with polysomnographic-confirmed RBD and 16 patients without RBD) and 25 healthy control subjects matched for age and educational level underwent sleep laboratory recordings and a comprehensive neuropsychological assessment.
  
  
  RESULTS
  Patients with PD and concomitant RBD showed significantly poorer performance on standardized tests measuring episodic verbal memory, executive functions, as well as visuospatial and visuoperceptual processing compared to both patients with PD without RBD and control subjects. Patients with PD without RBD had no detectable cognitive impairment compared to controls.
  
  
  CONCLUSIONS
  This study shows that cognitive impairment in nondemented patients with Parkinson disease (PD) is closely related to the presence of REM sleep behavior disorder, a sleep disturbance that was not controlled for in previous studies assessing cognitive deficits in PD.
authors.affiliation: CRCPC, Centre d'Etude du Sommeil et des Rythmes Biologiques, Hôpital du Sacré-Coeur de Montréal, 5400 Boul. Gouin Ouest, Montréal, Québec, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Vendette
authors.forename: J-F
authors.initials: JF
authors.lastname: Gagnon
authors.forename: A
authors.initials: A
authors.lastname: Décary
authors.forename: J
authors.initials: J
authors.lastname: Massicotte-Marquez
authors.forename: R B
authors.initials: RB
authors.lastname: Postuma
authors.forename: J
authors.initials: J
authors.lastname: Doyon
authors.forename: M
authors.initials: M
authors.lastname: Panisset
authors.forename: J
authors.initials: J
authors.lastname: Montplaisir
mesh_terms: D000367:Age Factors; D000368:Aged; D000375:Aging / Q000502:physiology; D001921:Brain / Q000503:physiopathology*; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology* / Q000523:psychology; D003866:Depressive Disorder / Q000453:epidemiology; D018450:Disease Progression; D004522:Educational Status; D006801:Humans; D008569:Memory Disorders / Q000175:diagnosis / Q000209:etiology / Q000523:psychology; D008875:Middle Aged; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications* / Q000503:physiopathology / Q000523:psychology; D010468:Perceptual Disorders / Q000175:diagnosis / Q000209:etiology / Q000523:psychology; D017286:Polysomnography; D011237:Predictive Value of Tests; D011379:Prognosis; D020187:REM Sleep Behavior Disorder / Q000150:complications* / Q000175:diagnosis / Q000523:psychology; D012120:Respiration Disorders / Q000453:epidemiology; D012680:Sensitivity and Specificity