Cognitive processing speed has minimal influence on the construct validity of Multiple Sclerosis Walking Scale-12 scores

J Neurol Sci. 2013 Dec 15;335(1-2):169-73. doi: 10.1016/j.jns.2013.09.024. Epub 2013 Sep 24.

Abstract

Background: The Multiple Sclerosis Walking Scale-12 (MSWS-12) has been a commonly used patient reported outcome for measuring walking impairment in research involving multiple sclerosis (MS).

Objective: We examined the possibility that cognitive processing speed (CPS) influences the association between MSWS-12 scores and other measures of ambulation (i.e., construct validity).

Methods: 96 MS patients completed the MSWS-12, underwent a neurological examination for generating an Expanded Disability Status Scale (EDSS) score, and completed the Symbol Digit Modalities Test (SDMT), Timed 25-Foot Walk (T25FW), 4 trials on the GAITRite™ for generating the functional ambulatory profile (FAP) score, and Six-minute Walk (6MW).

Results: The SDMT was significantly correlated with MSWS-12 scores (r=-.428) and T25FW (r=-.459), 6MW (r=.512), FAP (r=.275), and EDSS (r=-.404) scores. There were statistically significant correlations between MSWS-12 and T25FW (r=.568), 6MW (r=-.680), FAP (r=-.595), and EDSS (r=.737) scores. Lastly, four separate hierarchical linear regression analyses indicated that, after controlling for age, gender, disease duration, and clinical course, T25FW, 6MW, FAP, and EDSS scores individually were significant correlates of MSWS-12 scores, and the associations (i.e., standardized beta-coefficients) were still statistically significant with minimal attenuation when controlling for SDMT scores.

Conclusion: There was minimal evidence that CPS influenced the construct validity of MSWS-12 scores.

Keywords: Cognition; Gait; Measurement; Multiple sclerosis; Validity; Walking.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Cognition Disorders / etiology*
  • Disability Evaluation
  • Female
  • Gait Disorders, Neurologic / etiology*
  • Humans
  • Male
  • Middle Aged
  • Mobility Limitation
  • Multiple Sclerosis / complications*
  • Neuropsychological Tests
  • Severity of Illness Index
  • Statistics as Topic
  • Walking / physiology*