title: Clinical significance of REM sleep behavior disorder in Parkinson's disease.
abstract: OBJECTIVE
  Rapid eye movement (REM) sleep behavior disorder (RBD) may be a risk factor for dementia development in patients with Parkinson's disease (PD); however, the role of subclinical RBD remains unknown. Patients with PD and clinical RBD, subclinical RBD, or with normal REM sleep were examined in a cross sectional study and a longitudinal follow-up.
  
  
  METHODS
  Interviews regarding RBD symptoms and polysomnographies were performed on 82 PD patients divided into RBD subcategories based on the presence/absence of REM sleep without atonia (RWA) and/or RBD symptoms. Descriptive variables were compared and patients were followed-up longitudinally for 21.4±10.8months.
  
  
  RESULTS
  The existence of RBD, but not subclinical RBD, was associated with orthostatic hypotension and levodopa dose equivalents (LDEs) in patients with PD. Kaplan-Myer curves indicated that the occurrence of dementia in the PD group with clinical RBD was significantly faster than in the PD group with normal REM sleep (p=0.013). A Cox hazard regression analysis revealed that development to PD with dementia was only significantly associated with the presence of clinical RBD (hazard ratio: 14.1, p=0.017).
  
  
  CONCLUSIONS
  Clinical RBD symptoms, but not subclinical RBD, were associated with the development of dementia in PD.
authors.affiliation: Division of Neurology, Department of Brain and Neurosciences, Faculty of Medicine, Tottori University, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Nomura
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Inoue
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Kagimura
authors.forename: Kenji
authors.initials: K
authors.lastname: Nakashima
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000978:Antiparkinson Agents / Q000009:adverse effects / Q000627:therapeutic use; D001341:Autonomic Nervous System / Q000503:physiopathology; D001794:Blood Pressure / Q000502:physiology; D003430:Cross-Sectional Studies; D003704:Dementia / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D004185:Disability Evaluation; D004305:Dose-Response Relationship, Drug; D005260:Female; D006321:Heart / Q000294:innervation; D006801:Humans; D007024:Hypotension, Orthostatic / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D053208:Kaplan-Meier Estimate; D007980:Levodopa / Q000009:adverse effects / Q000627:therapeutic use; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis* / Q000188:drug therapy / Q000453:epidemiology / Q000503:physiopathology; D017286:Polysomnography; D011379:Prognosis; D016016:Proportional Hazards Models; D020187:REM Sleep Behavior Disorder / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D012894:Sleep Stages / Q000502:physiology; D018667:Tilt-Table Test
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa