Validation of the Chinese version of the 12-Item multiple sclerosis walking scale in individuals with multiple sclerosis: a psychometric and item response theory analysis.

backgroundThe 12-item Multiple Sclerosis Walking Scale (MSWS-12) is widely used to assess patient-perceived walking disability in individuals with multiple sclerosis (MS). Despite its international application, a validated Mandarin version has been lacking. This study aimed to translate and validate the Chinese version of the MSWS-12 and examine its psychometric properties using both classical test theory (CTT) and item response theory (IRT) approaches.

methodsThe MSWS-12 was translated into Chinese following international guidelines, including forward and backward translation, expert panel review, and cognitive debriefing. Cognitive debriefing was conducted with 20 individuals with MS (10 urban, 10 rural; 40% with a high school education or lower), confirming that all items were clear, culturally relevant, and conceptually equivalent. Participants were recruited from neurology clinics and included adults with clinically confirmed MS who had sufficient cognitive and physical function to complete the self-report instrument. Measurement properties were evaluated in accordance with the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) guideline, including internal consistency, test-retest reliability, structural validity, measurement invariance, and item-level analysis using the Graded Response Model (GRM).

resultsParticipants (N = 292) had a mean age of 41.72 years (SD = 5.23), with 60.6% identifying as female, and represented a diverse educational backgrounds. The Chinese version of the MSWS-12 demonstrated excellent internal consistency (Cronbach's α = 0.92; McDonald's ω = 0.91) and strong test-retest reliability (intraclass correlation coefficient [ICC] = 0.91, 95% CI [0.86, 0.94]), indicating high temporal stability. CFA supported a unidimensional structure with excellent model fit (CFI = 0.987, TLI = 0.984, IFI = 0.987, SRMR = 0.032, RMSEA = 0.038. 90% CI [0.015, 0.056]). Measurement invariance was confirmed across sex, residency, and disease duration at configural, metric, scalar, and strict levels (ΔCFI < 0.010, ΔRMSEA < 0.015). IRT analysis showed high item discrimination parameters (α = 2.01 - 2.95) and well-ordered respnse thresholds. No evidence of differential item functioning (DIF) was found (Δpseudo-R² < 0.02). Criterion-related validity was supported by strong correlations with the T25FW (r = .64, 95% CI [0.57, 0.70]) and the 6MWT (r = -.61, 95% CI [-0.67, -0.53]). Convergent validity was indicated by moderate associations with the EDSS (r = .47, 95% CI [0.37, 0.55]) and the MFIS (r = .45, 95% CI [0.36, 0.54]), while discriminant validity was confirmed by a weak association with the PHQ-9 (r = .28, 95% CI [0.17, 0.38]).

conclusionThe Chinese version of the MSWS-12 is a psychometrically sound, culturally valid tool for assessing ambulatory disability in Mandarin-speaking individuals with MS. Its demonstrated reliability, validity, and measurement invariance support its application in clinical practice and cross-cultural research.