title: Validation of a polysomnographic score for REM sleep behavior disorder.
abstract: OBJECTIVE
  Rapid eye movement (REM) sleep behavior disorder (RBD) was described more than 2 decades ago, but only 1 report on 5 patients and 5 normal subjects has tested the effectiveness of a method by which relevant polysomnographic findings can be quantified. We sought to validate this method in a larger sample of patients and control subjects.
  
  
  METHODS
  Cross-sectional.
  
  
  METHODS
  Academic hospital.
  
  
  METHODS
  A clinician interviewed 17 patients at risk for RBD secondary to neurodegenerative disorders and 6 controls to assess whether RBD was present by history. Bed partners completed a questionnaire that quantified RBD symptom severity. From 2 consecutive nocturnal studies in each patient, 2 different polysomnographic RBD scores were generated: the percentage of 30-second REM epochs with at least 15 seconds of tonically maintained electromyographic activity, and the percentage of 3-second REM mini-epochs that contained phasic electromyographic bursts.
  
  
  RESULTS
  The tonic and phasic measures, combined together, were higher in patients with clinical determinations of probable or possible RBD (n=9) than in patients judged unlikely to have RBD (n=4, P = .023). The overall polysomnographic measure correlated with the symptom scores (rho = 0.42, P = .048). Specific polysomnographic RBD measures on night 1 correlated highly with those on night 2 (rho > 0.70, P < .0001).
  
  
  CONCLUSIONS
  This quantitative method to assess the severity of RBD polysomnographic features appears to be both valid and reliable in patients at risk for RBD because of neurodegenerative disorders.
authors.affiliation: University of Michigan, Ann Arbor, MI, USA. fconsens@umich.edu
authors.forename: Flavia B
authors.initials: FB
authors.lastname: Consens
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Chervin
authors.forename: Robert A
authors.initials: RA
authors.lastname: Koeppe
authors.forename: Roderick
authors.initials: R
authors.lastname: Little
authors.forename: Suyu
authors.initials: S
authors.lastname: Liu
authors.forename: Larry
authors.initials: L
authors.lastname: Junck
authors.forename: Karen
authors.initials: K
authors.lastname: Angell
authors.forename: Mary
authors.initials: M
authors.lastname: Heumann
authors.forename: Sid
authors.initials: S
authors.lastname: Gilman
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D004576:Electromyography; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography / Q000379:methods*; D020187:REM Sleep Behavior Disorder / Q000175:diagnosis*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires