Cross-cultural adaptation and validation of the Arabic version of the Multiple Sclerosis Impact Scale-29.

Abstract

The Multiple Sclerosis Impact Scale-29 (MSIS-29) is a patient self-reported outcome (PRO) that measures patients' quality of life, and it is divided into two sub-scales for the physical (PHYS) and psychological (PSYCH) domains. This study aimed to translate the MSIS-29 into Arabic, cross-culturally adapt it, and examine its psychometric properties. One hundred fifty patients with MS completed the MSIS-29-Ar, the Functional Assessment of Multiple Sclerosis (FAMS), and the Short-Form Health Survey (SF-36). After one week, 60 participants were asked to complete the MSIS-29-Ar again to examine test-retest reliability. The MSIS-29-Ar was clear and understandable among patients with MS in Saudi Arabia. The internal consistency for the MSIS-29-Ar-PHYS was excellent, with a Cronbach's alpha of 0.955, and was good for the MSIS-29-Ar-PSYCH, with a Cronbach's alpha of 0.891. The test-retest reliability for MSIS-29-Ar-PHYS was ICC_2,1 = 0.97; 95% confidence interval (0.93, 0.99) and ICC_2,1 = 0.95.; 95% confidence interval (0.897, 0.976) for MSIS-29-Ar-PSYCH domains. The minimal detectable change with 95% confidence (MDC₉₅) was 10.28 and 13.37 for the MSIS-29-Ar-PHYS and MSIS-29-Ar-PSYCH, respectively. No floor and ceiling effects were observed. Convergent and divergent validity was supported by 75% of the predefined hypotheses and correlated with the other health-related quality-of-life measures, SF-36 and FAMS. The MSIS-29-Ar questionnaire is a valid and reliable outcome measure among Saudi patients with MS.IMPLICATION FOR REHABILITATIONRehabilitation specialists can confidently interpret patient scores in the MSIS-29-Ar to measure physical and psychological factors impacting patients' quality of life with Multiple Sclerosis (MS).Patients with unchanged clinical status will have similar scores in the MSIS-29-Ar with repeated scale administrations over time.The MSIS-29-Ar can be used in clinical practice and research studies to measure factors that impact the quality of life in Arabic-speaking patients with MS.