title: Walking and cognition, but not symptoms, correlate with dual task cost of walking in multiple sclerosis.
abstract: BACKGROUND
  Performing a cognitive task while walking results in a reduction of walking performance among persons with MS. To date, very little is known about correlates of this dual task cost (DTC) of walking in MS.
  
  
  OBJECTIVE
  We examined walking performance, cognitive processing speed, and symptoms of fatigue, depression, anxiety, and pain as correlates of DTC of walking in MS.
  
  
  METHODS
  82 persons with MS undertook a 6-min walk test (6MWT) and completed the Symbol Digit Modalities Test (SDMT), Fatigue Severity Scale (FSS), Short-form of the McGill Pain Questionnaire (SF-MPQ), Hospital Anxiety and Depression Scale (HADS), and self-reported Expanded Disability Status Scale (SR-EDSS). The participants completed 4 trials of walking at a self-selected pace on an electronic walkway that recorded spatiotemporal parameters of gait. The first 2 trials were performed without a cognitive task, whereas the second 2 trials were completed while performing a modified Word List Generation task.
  
  
  RESULTS
  There were significant and large declines in gait performance with the addition of a cognitive task for velocity (p<.001, η2=.52), cadence (p<.001, η2=.49), and step length (p<.001, η2=.23). 6MWT and SDMT scores correlated with DTC for velocity (r=-.41, p<.001 and r=-.32, p<.001, respectively) and step length (r=-.45, p<.001 and r=-.37, p<.001, respectively); there were no significant associations between FSS, SF-MPQ, and HADS scores with the DTC of walking. Regression analyses indicated that 6MW, but not SDMT, explained variance in DTC for velocity (ΔR2=.11, p<.001) and step length (ΔR2=.13, p<.001), after controlling for SR-EDSS scores.
  
  
  CONCLUSIONS
  Walking performance might be a target of interventions for reducing the DTC of walking in MS.
authors.affiliation: Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, United States. Electronic address: robmotl@illinois.edu.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Motl
authors.affiliation: Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, United States.
authors.forename: Jacob J
authors.initials: JJ
authors.lastname: Sosnoff
authors.affiliation: Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, United States.
authors.forename: Deirdre
authors.initials: D
authors.lastname: Dlugonski
authors.affiliation: Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, United States.
authors.forename: Lara A
authors.initials: LA
authors.lastname: Pilutti
authors.affiliation: Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, United States.
authors.forename: Rachel
authors.initials: R
authors.lastname: Klaren
authors.affiliation: Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, United States.
authors.forename: Brian M
authors.initials: BM
authors.lastname: Sandroff
mesh_terms: D000328:Adult; D001007:Anxiety / Q000503:physiopathology; D003071:Cognition / Q000502:physiology*; D003863:Depression / Q000503:physiopathology; D004185:Disability Evaluation; D005221:Fatigue / Q000503:physiopathology; D005260:Female; D005684:Gait / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000503:physiopathology* / Q000523:psychology; D010147:Pain Measurement; D011597:Psychomotor Performance / Q000502:physiology*; D016138:Walking / Q000502:physiology*
keywords: Cognition; Fatigue; Gait; Multiple sclerosis; Walking