title: Walking impairs cognitive performance among people with multiple sclerosis but not controls.
abstract: People with multiple sclerosis (MS) complain of problems completing two tasks simultaneously; sometimes called 'dual-tasking' (DT). Previous research in DT among people with MS has focused on how adding a cognitive task interferes with gait and few have measured how adding a motor task could interfere with cognition. We aimed to determine the extent to which walking affects a concurrent working memory task in people with MS compared to healthy controls. We recruited MS participants (n=13) and controls (n=10) matched by age (±3years), education (±3years) and gender. Participants first completed the cognitive task (subtracting 7's from the previous number) and then again while walking on an instrumented walkway. Although there were no baseline differences in cognition or walking between MS participants and controls, MS participants demonstrated a 52% decrease in number of correct answers during DT (p<0.001). Mental Tracking Rate (% correct answers/min) correlated strongly with MS-related disability measured using the Expanded Disability Status Scale (EDSS; r(11)=-0.68, p<0.01). We propose that compromised mental tracking during walking could be related to limited neural resource capacity and could be a potentially useful outcome measure to detect ecologically valid dual tasking impairments.
authors.affiliation: Recovery & Performance Laboratory, Faculty of Medicine, Memorial University, Rm 400, 100 Forest Rd., St. John's, NL A1A 1E5, Canada.
authors.forename: Matthew B
authors.initials: MB
authors.lastname: Downer
authors.affiliation: Recovery & Performance Laboratory, Faculty of Medicine, Memorial University, Rm 400, 100 Forest Rd., St. John's, NL A1A 1E5, Canada.
authors.forename: Megan C
authors.initials: MC
authors.lastname: Kirkland
authors.affiliation: Recovery & Performance Laboratory, Faculty of Medicine, Memorial University, Rm 400, 100 Forest Rd., St. John's, NL A1A 1E5, Canada.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Wallack
authors.affiliation: Recovery & Performance Laboratory, Faculty of Medicine, Memorial University, Rm 400, 100 Forest Rd., St. John's, NL A1A 1E5, Canada. Electronic address: Michelle.ploughman@med.mun.ca.
authors.forename: Michelle
authors.initials: M
authors.lastname: Ploughman
mesh_terms: D000328:Adult; D001288:Attention / Q000502:physiology*; D001921:Brain / Q000503:physiopathology; D003072:Cognition Disorders / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology*; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology*; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000175:diagnosis / Q000503:physiopathology* / Q000523:psychology*; D009460:Neurologic Examination; D009483:Neuropsychological Tests; D011340:Problem Solving / Q000502:physiology; D011597:Psychomotor Performance; D016138:Walking / Q000502:physiology* / Q000523:psychology*
keywords: Cognition; Cognitive motor interference; Dual-task ability; Gait; Neurodegenerative disease; Rehabilitation