Confirmation and extension of the validity of the Multiple Sclerosis Walking Scale-12 (MSWS-12)

Objective: The Multiple Sclerosis Walking Scale-12 (MSWS-12) is a 12-item patient-rated measure of the impact of MS on walking. As validation of scores from a measure is an ongoing and evolving process, the provision of additional evidence is warranted that confirms and extends the validity of inferences from scores on the MSWS-12. Method: Participants (N = 133) were recruited through support group meetings of the Greater Illinois and Indiana State Chapters of the National Multiple Sclerosis Society, and wore an accelerometer for a seven-day period and completed the MSWS-12 and other outcome measures. Results: Confirmatory factor analysis indicated that a single-factor model provided an adequate fit for MSWS-12 scores. MSWS-12 scores demonstrated strong evidence of internal consistency. The correlations between MSWS-12 scores with scores from other scales, including an accelerometer, were consistent with our a priori hypotheses. Conclusion: We provide evidence that both confirms and extends the validity of inferences from scores of the MSWS-12 as a measure of the impact of MS on walking in a community-based sample of individuals with MS.