title: Slow wave sleep in the chronically fatigued: Power spectra distribution patterns in chronic fatigue syndrome and primary insomnia.
abstract: OBJECTIVE
  To investigate slow wave sleep (SWS) spectral power proportions in distinct clinical conditions sharing non-restorative sleep and fatigue complaints without excessive daytime sleepiness (EDS), namely the chronic fatigue syndrome (CFS) and primary insomnia (PI). Impaired sleep homeostasis has been suspected in both CFS and PI.
  
  
  METHODS
  We compared perceived sleep quality, fatigue and sleepiness symptom-intensities, polysomnography (PSG) and SWS spectral power distributions of drug-free CFS and PI patients without comorbid sleep or mental disorders, with a good sleeper control group.
  
  
  RESULTS
  Higher fatigue without EDS and impaired perceived sleep quality were confirmed in both patient groups. PSG mainly differed in sleep fragmentation and SWS durations. Spectral analysis revealed a similar decrease in central ultra slow power (0.3-0.79Hz) proportion during SWS for both CFS and PI and an increase in frontal power proportions of faster frequencies during SWS in PI only. The latter was correlated to affective symptoms whereas lower central ultra slow power proportions were related to fatigue severity and sleep quality impairment.
  
  
  CONCLUSIONS
  In combination with normal (PI) or even increased SWS durations (CFS), we found consistent evidence for lower proportions of slow oscillations during SWS in PI and CFS.
  
  
  CONCLUSIONS
  Observing normal or increased SWS durations but lower proportions of ultra slow power, our findings suggest a possible quantitative compensation of altered homeostatic regulation.
authors.affiliation: Brugmann University Hospital, Sleep Laboratory & Unit for Chronobiology U78, Université Libre de Bruxelles (U.L.B.), Brussels, Belgium; UNI, ULB Neurosciences Institute, Faculty of Medicine, Laboratory for Medical Psychology ULB312, Université Libre de Bruxelles (U.L.B.), Brussels, Belgium. Electronic address: daniel.neu@chu-brugmann.be.
authors.forename: Daniel
authors.initials: D
authors.lastname: Neu
authors.affiliation: Brugmann University Hospital, Sleep Laboratory & Unit for Chronobiology U78, Université Libre de Bruxelles (U.L.B.), Brussels, Belgium; UNI, ULB Neurosciences Institute, Faculty of Medicine, Laboratory for Medical Psychology ULB312, Université Libre de Bruxelles (U.L.B.), Brussels, Belgium; Department of Experimental and Applied Psychology (EXTO), Vrije Universiteit Brussel (V.U.B.), Brussels, Belgium; Royal Military Academy, Department LIFE, Brussels, Belgium. Electronic address: olivier.mairesse@chu-brugmann.be.
authors.forename: Olivier
authors.initials: O
authors.lastname: Mairesse
authors.affiliation: Brugmann University Hospital, Sleep Laboratory & Unit for Chronobiology U78, Université Libre de Bruxelles (U.L.B.), Brussels, Belgium; UNI, ULB Neurosciences Institute, Faculty of Medicine, Laboratory for Medical Psychology ULB312, Université Libre de Bruxelles (U.L.B.), Brussels, Belgium.
authors.forename: Paul
authors.initials: P
authors.lastname: Verbanck
authors.affiliation: UNI, ULB Neurosciences Institute, Faculty of Medicine, Laboratory for Medical Psychology ULB312, Université Libre de Bruxelles (U.L.B.), Brussels, Belgium; Tivoli University Hospital, Department of Psychiatry, U.L.B., La Louvière, Belgium.
authors.forename: Olivier
authors.initials: O
authors.lastname: Le Bon
mesh_terms: D000328:Adult; D058256:Brain Waves / Q000502:physiology*; D004569:Electroencephalography / Q000379:methods; D015673:Fatigue Syndrome, Chronic / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography / Q000379:methods; D012890:Sleep / Q000502:physiology*; D007319:Sleep Initiation and Maintenance Disorders / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: Chronic fatigue syndrome; Fatigue; Polysomnography; Primary insomnia; Sleepiness; Slow wave sleep; Spectral analysis; Ultra slow delta