title: Fatigue in multiple sclerosis is closely related to sleep disorders: a polysomnographic cross-sectional study.
abstract: BACKGROUND
  Sleep disorders can cause tiredness. The relationship between sleep disorders and fatigue in patients with multiple sclerosis (MS) has not yet been investigated systematically.
  
  
  OBJECTIVE
  To investigate the relationship between fatigue and sleep disorders in patients with MS.
  
  
  METHODS
  Some 66 MS patients 20 to 66 years old were studied by overnight polysomnography. Using a cut-off point of 45 in the Modified Fatigue Impact Scale (MFIS), the entire cohort was stratified into a fatigued MS subgroup (n=26) and a non-fatigued MS subgroup (n=40).
  
  
  RESULTS
  Of the fatigued MS patients, 96% (n=25) were suffering from a relevant sleep disorder, along with 60% of the non-fatigued MS patients (n=24) (p=0.001). Sleep-related breathing disorders were more frequent in the fatigued MS patients (27%) than in the non-fatigued MS patients (2.5%). Significantly higher MFIS values were detected in all (fatigued and non-fatigued) patients with relevant sleep disorders (mean MFIS 42.8; SD 18.3) than in patients without relevant sleep disorders (mean MFIS 20.5; SD 17.0) (p<0.001). Suffering from a sleep disorder was associated with an increased risk of fatigue in MS (odds ratio: 18.5; 95% CI 1.6-208; p=0.018).
  
  
  CONCLUSIONS
  Our results demonstrate a clear and significant relationship between fatigue and sleep disorders.
authors.affiliation: Hanse-Klinikum, Department of Neurology, Stralsund, Germany. cveauthier@web.de
authors.forename: C
authors.initials: C
authors.lastname: Veauthier
authors.forename: H
authors.initials: H
authors.lastname: Radbruch
authors.forename: G
authors.initials: G
authors.lastname: Gaede
authors.forename: C F
authors.initials: CF
authors.lastname: Pfueller
authors.forename: J
authors.initials: J
authors.lastname: Dörr
authors.forename: J
authors.initials: J
authors.lastname: Bellmann-Strobl
authors.forename: K-D
authors.initials: KD
authors.lastname: Wernecke
authors.forename: F
authors.initials: F
authors.lastname: Zipp
authors.forename: F
authors.initials: F
authors.lastname: Paul
authors.forename: J P
authors.initials: JP
authors.lastname: Sieb
mesh_terms: D000328:Adult; D000368:Aged; D003430:Cross-Sectional Studies; D005221:Fatigue / Q000175:diagnosis / Q000209:etiology* / Q000503:physiopathology; D005260:Female; D005858:Germany; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D016017:Odds Ratio; D017286:Polysomnography; D018570:Risk Assessment; D012307:Risk Factors; D012890:Sleep; D012893:Sleep Wake Disorders / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D011795:Surveys and Questionnaires; D055815:Young Adult