title: Decreased sleep spindle density in patients with idiopathic REM sleep behavior disorder and patients with Parkinson's disease.
abstract: OBJECTIVE
  To determine whether sleep spindles (SS) are potentially a biomarker for Parkinson's disease (PD).
  
  
  METHODS
  Fifteen PD patients with REM sleep behavior disorder (PD+RBD), 15 PD patients without RBD (PD-RBD), 15 idiopathic RBD (iRBD) patients and 15 age-matched controls underwent polysomnography (PSG). SS were scored in an extract of data from control subjects. An automatic SS detector using a Matching Pursuit (MP) algorithm and a Support Vector Machine (SVM) was developed and applied to the PSG recordings. The SS densities in N1, N2, N3, all NREM combined and REM sleep were obtained and evaluated across the groups.
  
  
  RESULTS
  The SS detector achieved a sensitivity of 84.7% and a specificity of 84.5%. At a significance level of α=1%, the iRBD and PD+RBD patients had a significantly lower SS density than the control group in N2, N3 and all NREM stages combined. At a significance level of α=5%, PD-RBD had a significantly lower SS density in N2 and all NREM stages combined.
  
  
  CONCLUSIONS
  The lower SS density suggests involvement in pre-thalamic fibers involved in SS generation. SS density is a potential early PD biomarker.
  
  
  CONCLUSIONS
  It is likely that an automatic SS detector could be a supportive diagnostic tool in the evaluation of iRBD and PD patients.
authors.affiliation: Department of Electrical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark; Danish Center for Sleep Medicine University of Copenhagen, Glostrup Hospital, Glostrup, Denmark. Electronic address: julie.a.e.christensen@gmail.com.
authors.forename: Julie A E
authors.initials: JA
authors.lastname: Christensen
authors.affiliation: Department of Electrical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark; Danish Center for Sleep Medicine University of Copenhagen, Glostrup Hospital, Glostrup, Denmark.
authors.forename: Jacob
authors.initials: J
authors.lastname: Kempfner
authors.affiliation: Danish Center for Sleep Medicine University of Copenhagen, Glostrup Hospital, Glostrup, Denmark; Department of Neurology, Bispebjerg Hospital, Copenhagen, Denmark.
authors.forename: Marielle
authors.initials: M
authors.lastname: Zoetmulder
authors.affiliation: Danish Center for Sleep Medicine University of Copenhagen, Glostrup Hospital, Glostrup, Denmark.
authors.forename: Helle L
authors.initials: HL
authors.lastname: Leonthin
authors.affiliation: H. Lundbeck A/S, Copenhagen, Denmark.
authors.forename: Lars
authors.initials: L
authors.lastname: Arvastson
authors.affiliation: H. Lundbeck A/S, Copenhagen, Denmark.
authors.forename: Søren R
authors.initials: SR
authors.lastname: Christensen
authors.affiliation: Department of Electrical Engineering, Technical University of Denmark, Kongens Lyngby, Denmark.
authors.forename: Helge B D
authors.initials: HB
authors.lastname: Sorensen
authors.affiliation: Danish Center for Sleep Medicine University of Copenhagen, Glostrup Hospital, Glostrup, Denmark; Center for Healthy Ageing, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Poul
authors.initials: P
authors.lastname: Jennum
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications* / Q000523:psychology*; D017286:Polysomnography; D020187:REM Sleep Behavior Disorder / Q000209:etiology* / Q000503:physiopathology*; D012680:Sensitivity and Specificity; D012895:Sleep, REM / Q000502:physiology; D013788:Thalamus / Q000503:physiopathology
keywords: Automatic detection; Matching Pursuit; Parkinson’s disease; REM sleep behavior disorder; Sleep spindles; Support Vector Machine