title: Accelerometry in persons with multiple sclerosis: measurement of physical activity or walking mobility?
abstract: OBJECTIVE
  Motion sensors such as accelerometers have been recognized as an ideal measure of physical activity in persons with MS. This study examined the hypothesis that accelerometer movement counts represent a measure of both physical activity and walking mobility in individuals with MS.
  
  
  METHODS
  The sample included 269 individuals with a definite diagnosis of relapsing-remitting MS who completed the Godin Leisure-Time Exercise Questionnaire (GLTEQ), International Physical Activity Questionnaire (IPAQ), Multiple Sclerosis Walking Scale-12 (MSWS-12), Patient Determined Disease Steps (PDDS), and then wore an ActiGraph accelerometer for 7days. The data were analyzed using bivariate correlation and confirmatory factor analysis.
  
  
  RESULTS
  The results indicated that (a) the GLTEQ and IPAQ scores were strongly correlated and loaded significantly on a physical activity latent variable, (b) the MSWS-12 and PDDS scores strongly correlated and loaded significantly on a walking mobility latent variable, and (c) the accelerometer movement counts correlated similarly with the scores from the four self-report questionnaires and cross-loaded on both physical activity and walking mobility latent variables.
  
  
  CONCLUSIONS
  Our data suggest that accelerometers are measuring both physical activity and walking mobility in persons with MS, whereas self-report instruments are measuring either physical activity or walking mobility in this population.
authors.affiliation: Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
authors.forename: Madeline
authors.initials: M
authors.lastname: Weikert
authors.forename: Robert W
authors.initials: RW
authors.lastname: Motl
authors.forename: Yoojin
authors.initials: Y
authors.lastname: Suh
authors.forename: Edward
authors.initials: E
authors.lastname: McAuley
authors.forename: Daniel
authors.initials: D
authors.lastname: Wynn
mesh_terms: D000054:Acceleration; D000203:Activities of Daily Living; D000328:Adult; D004185:Disability Evaluation; D018450:Disease Progression; D015444:Exercise / Q000502:physiology; D005080:Exercise Test / Q000379:methods; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D020233:Gait Disorders, Neurologic / Q000175:diagnosis* / Q000209:etiology* / Q000503:physiopathology; D006304:Health Status; D006306:Health Surveys; D006801:Humans; D007899:Leisure Activities; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D009103:Multiple Sclerosis / Q000150:complications*; D005082:Physical Exertion; D010809:Physical Fitness / Q000502:physiology; D011594:Psychometrics; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D016138:Walking / Q000502:physiology*