title: Rapid eye movement sleep behavioral events: a new marker for neurodegeneration in early Parkinson disease?
abstract: OBJECTIVE
  To analyze potential markers in sleep for early recognition of neurodegenerative disease in newly diagnosed, unmedicated patients with Parkinson disease (PD) compared to controls.
  
  
  METHODS
  Videopolysomnography (vPSG) was available in 158 newly diagnosed, unmedicated patients with PD and 110 age-, sex-, and education-matched healthy controls (HC). Rapid eye movement (REM) sleep was analyzed for REM without atonia (RWA) and studied by review of time-synchronized video. Motor behaviors and/or vocalizations in REM sleep with a purposeful component other than comfort moves were identified as REM sleep behavioral events (RBE). Two or more events had to be present to be classified as "RBE positive." RBE subjects included rapid eye movement sleep behavior disorder (RBD) and non-RBD subjects based on the presence or absence of RWA > 18.2%.
  
  
  RESULTS
  RBE were detected in 81 of 158 patients with de novo PD (51%) and 17 of 110 HC (15%) (P < 0.001). RBD was identified in 40/81 RBE-positive patients with PD (25% of all PD patients) and 2 of 17 RBE-positive HC (2% of all controls). RBE-positive patients showed no specific motor or neuropsychological features compared to RBE-negative patients. Patients with PD and HC with RBE had more REM sleep (P = 0.002) and a higher periodic leg movements in sleep index (P = 0.022) compared to subjects without RBE.
  
  
  CONCLUSIONS
  This first description of REM sleep behavioral events (RBE) shows it occurs more frequently in patients with de novo Parkinson disease (PD) than in healthy controls and may be an early sign of neurodegeneration and precede rapid eye movement sleep behavior disorder (RBD). There is no specific phenotype of PD associated with newly defined RBE or RBD at this early stage.
authors.affiliation: Paracelsus-Elena-Klinik, Kassel, Germany ; Department of Neurology, Philipps-University Marburg, Germany.
authors.forename: Friederike
authors.initials: F
authors.lastname: Sixel-Döring
authors.affiliation: Paracelsus-Elena-Klinik, Kassel, Germany ; Department of Psychology, University Kassel, Germany.
authors.forename: Ellen
authors.initials: E
authors.lastname: Trautmann
authors.affiliation: Paracelsus-Elena-Klinik, Kassel, Germany ; Department of Neurosurgery, Georg-August University Goettingen, Germany ; Department of Neuropathology, Georg-August University, Goettingen, Germany.
authors.forename: Brit
authors.initials: B
authors.lastname: Mollenhauer
authors.affiliation: Paracelsus-Elena-Klinik, Kassel, Germany ; Department of Neurosurgery, Georg-August University Goettingen, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Trenkwalder
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D042241:Early Diagnosis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology*; D020187:REM Sleep Behavior Disorder / Q000150:complications* / Q000175:diagnosis*; D012895:Sleep, REM
keywords: Parkinson disease; REM sleep behavior disorder; REM sleep behavioral events; somnological marker