title: Self-reported fatigue and energy cost during walking are not related in patients with multiple sclerosis.
abstract: OBJECTIVE
  To determine whether there is a relationship between self-reported fatigue and the energy cost of walking (ECw), and how self-reported fatigue and ECw relate to physical functioning in patients with multiple sclerosis (MS).
  
  
  METHODS
  Cross-sectional cohort study, using structural equation modeling.
  
  
  METHODS
  Home environment and at a university medical center.
  
  
  METHODS
  Patients (N=75) were obtained from a longitudinal study on outcome measurement and functional prognosis in early MS. Patients were included if they were able to walk for 6 minutes without being assisted by a person. The age range was between 28.0 and 69.7 years and the median Expanded Disability Status Scale was 2.5 (range, 1.0-6.5).
  
  
  METHODS
  Not applicable.
  
  
  METHODS
  Self-reported fatigue was measured with the Fatigue Severity Scale, the vitality subscale of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36), and a visual analog scale. Physical functioning was determined with the physical functioning subscale of the SF-36, fast walking speed, and comfortable walking speed. The ECw (J·kg(-1)·m(-1)) was measured with the energy cost of the walking test.
  
  
  RESULTS
  The relationship between ECw and latent variable fatigue had a β=-.188 (P=.236), that between ECw and physical functioning (SF-36 physical functioning) had a β=-.344 (P=.001), and that between fatigue and physical functioning had a β=-.448 (P=.000).
  
  
  CONCLUSIONS
  Fatigue and ECw are not related in patients with MS with mild to moderate walking problems. ECw and fatigue are independent determinants of physical functioning.
authors.affiliation: Department of Rehabilitation Medicine, VU University Medical Center, Amsterdam, The Netherlands. j.kempen@vumc.nl
authors.forename: Jiska C E
authors.initials: JC
authors.lastname: Kempen
authors.forename: Vincent
authors.initials: V
authors.lastname: de Groot
authors.forename: Dirk L
authors.initials: DL
authors.lastname: Knol
authors.forename: Gustaaf J
authors.initials: GJ
authors.lastname: Lankhorst
authors.forename: Heleen
authors.initials: H
authors.lastname: Beckerman
mesh_terms: D000328:Adult; D000368:Aged; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D004734:Energy Metabolism; D005221:Fatigue / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009103:Multiple Sclerosis / Q000503:physiopathology*; D011446:Prospective Studies; D057566:Self Report; D012720:Severity of Illness Index; D016138:Walking / Q000502:physiology*