Validity of Scores From the 12-Item Multiple Sclerosis Walking Scale Among Young, Middle-Aged, and Older Adults With Multiple Sclerosis.

OBJECTIVE

To examine the construct validity of inferences from scores on the 12-item multiple sclerosis walking scale (MSWS-12) as a patient-reported outcome measure of walking dysfunction among young, middle-aged, and older adults with multiple sclerosis (MS).

DESIGN

Cross-sectional, comparative research design.

SETTING

University research laboratory.

PARTICIPANTS

The sample included 187 participants (N=187) with MS who were categorized into young (20-39y, n=50), middle-aged (40-59y, n=83), and older (60-79y, n=54) adult age groups.

INTERVENTIONS: Not applicable.

MAIN OUTCOME MEASURES: The participants completed the MSWS-12; the timed 25-foot walk, 6-minute walk, and timed Up and Go; and the Brief International Cognitive Assessment for MS. The data analyses were performed using IBM SPSS Version 29.0.2.0 for the iOS platform.

RESULTS

There were similar patterns of linear worsening of scores for the MSWS-12 (F1,187=12.7, P<.001, η2=0.07), timed 25-foot walk (F1,187=11.5, P<.001, η2=0.06), 6-minute walk (F1,187=13.1, P<.001, η2=0.08), and timed Up and Go (F1,184=10.8, P<.001, η2=0.06) across the 3 age groups. MSWS-12 scores had strong partial correlations with timed 25-foot walk, 6-minute walk, and timed Up and Go in the overall sample (partial r's of 0.59, 0.66, 0.55, respectively) and across the 3 age groups, when controlling for Brief International Cognitive Assessment for MS outcomes.

CONCLUSIONS

We provide new evidence for the construct validity of MSWS-12 scores as a patient-reported outcome measure of walking dysfunction across the adult lifespan in MS. Our results, in particular, support the application of the MSWS-12 in clinical research and practice involving older adults with MS who experience the combined effects of advanced age and MS disease progression.