title: Night-to-night variability of muscle tone, movements, and vocalizations in patients with REM sleep behavior disorder.
abstract: OBJECTIVE
  The video-polysomnographic criteria of REM sleep behavior disorder (RBD) have not been well described. We evaluated the between-night reproducibility of phasic and tonic enhanced muscle activity during REM sleep as well as the associated behaviors and vocalizations of the patients.
  
  
  METHODS
  Fifteen patients with clinical RBD underwent two consecutive video-polysomnographies. The amount of excessive phasic and tonic chin muscle activity during REM sleep was measured in 15 patients in 3-sec mini-epochs. The time spent with motor (minor, major, complex, and scenic) or vocal (sounds, mumblings, and comprehensible speeches) events was measured in 7 patients during REM sleep.
  
  
  RESULTS
  There was a good between-night agreement for tonic (Spearman rho = 0.55, p = 0.03; Kendall tau = 0.48, p = 0.01) but not for phasic (rho = 0.47, p = 0.1; tau = 0.31, p = 0.1) excessive chin muscle activity. On the video and audio recordings, the minor RBD behaviors tended to occur more frequently during the second night than the first, whereas the patients spoke longer during the first than the second night.
  
  
  CONCLUSIONS
  The excessive tonic activity during REM sleep is a reliable marker of RBD. It could represent the extent of dysfunction in the permissive atonia systems. In contrast, the more variable phasic activity and motor/vocal events could be more dependent on dream content (executive systems).
authors.affiliation: Sleep Disorder Unit, Pitié-Salpêtrière Hospital, APHP, and Centre de Recherche de l'Institut du Cerveau et de la Moelle epiniere, UPMC-Paris 6, Inserm UMR_S 975, CNRS UMR 7225, France.
authors.forename: Fanny
authors.initials: F
authors.lastname: Cygan
authors.forename: Delphine
authors.initials: D
authors.lastname: Oudiette
authors.forename: Laurène
authors.initials: L
authors.lastname: Leclair-Visonneau
authors.forename: Smaranda
authors.initials: S
authors.lastname: Leu-Semenescu
authors.forename: Isabelle
authors.initials: I
authors.lastname: Arnulf
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002940:Circadian Rhythm; D015331:Cohort Studies; D004576:Electromyography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009129:Muscle Tonus / Q000502:physiology*; D017286:Polysomnography / Q000379:methods; D020187:REM Sleep Behavior Disorder / Q000175:diagnosis* / Q000503:physiopathology; D018570:Risk Assessment; D012720:Severity of Illness Index; D013060:Speech; D018709:Statistics, Nonparametric; D013997:Time Factors; D014741:Video Recording