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Multiple Sclerosis International
Volume 2015 (2015), Article ID 650645, 7 pages
Research Article

Comparing Three Dual-Task Methods and the Relationship to Physical and Cognitive Impairment in People with Multiple Sclerosis and Controls

Recovery & Performance Laboratory, L.A. Miller Centre, Faculty of Medicine, Memorial University, 100 Forest Road, St. John’s, NL, Canada A1A 1E5

Received 7 July 2015; Revised 21 October 2015; Accepted 2 November 2015

Academic Editor: Wolfgang Bruck

Copyright © 2015 Megan C. Kirkland et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Dual-tasking (DT) is a measure to detect impairments in people with multiple sclerosis (MS). We compared three DT methods to determine whether cognitive (Montreal Cognitive Assessment (MoCA)) or physical disability (Expanded Disease Severity Scale; EDSS) was related to DT performance. We recruited MS participants with low disability (<3 EDSS, ) and high disability (≥3 EDSS, ) and matched controls (). Participants walked at self-selected (SS) speed on an instrumented walkway (Protokinetics, Havertown, USA), followed by DT walks in randomized order: DT ABC (reciting every second letter of the alphabet), DT 7 (serially subtracting 7’s from 100), and DT 3 (counting upwards, leaving out multiples and numbers that include 3). DT 7 resulted in the most consistent changes in performance. Both MS and control groups reduced velocity and cadence and shortened step length during DT with no significant differences between groups. Control subjects widened stride width by about 1 cm while MS subjects (collapsed as one group) did not. MS subjects with higher disability significantly increased percentage time in double support during DT compared to SS (, ). The change in DS was related to cognitive and not physical disability (,).