title: Longitudinal assessment of probable rapid eye movement sleep behaviour disorder in Parkinson's disease.
abstract: OBJECTIVE
  Rapid eye movement (REM) sleep behaviour disorder (RBD) is frequently present in patients with Parkinson's disease (PD) and may have prognostic implications. There are few longitudinal studies of RBD in patients with PD. Our aim was to investigate whether RBD was a persistent feature in a follow-up study of 107 patients with PD.
  
  
  METHODS
  After a mean follow-up time of 3 years, 96 patients were available for reassessment. Probable RBD (pRBD) was diagnosed by the REM sleep behaviour disorder screening questionnaire.
  
  
  RESULTS
  At follow-up, pRBD was found in 49% of the patients, versus 38% at baseline. The pRBD status remained unchanged in three-quarters of the patients, whilst 17% had new pRBD symptoms. Disease duration was longer in the pRBD group, 9.4 vs. 7.6 years (P = 0.02).
  
  
  CONCLUSIONS
  Probable RBD is a persistent feature in PD and probably increases over time.
authors.affiliation: Department of Neurology, Drammen Hospital, Vestre Viken Hospital Trust, Drammen, Norway.
authors.forename: K A
authors.initials: KA
authors.lastname: Bjørnarå
authors.affiliation: Department of Neurology, Oslo University Hospital, Oslo, Norway.|Faculty of Medicine, University of Oslo, Oslo, Norway.
authors.forename: E
authors.initials: E
authors.lastname: Dietrichs
authors.affiliation: Department of Neurology, Oslo University Hospital, Oslo, Norway.
authors.forename: M
authors.initials: M
authors.lastname: Toft
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications*; D020187:REM Sleep Behavior Disorder / Q000175:diagnosis / Q000209:etiology*
keywords: Parkinson's disease; REM sleep behaviour disorder; REM sleep behaviour disorder screening questionnaire; longitudinal