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

Abstract

Purpose

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.

Materials and Methods

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.

Results

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.

Conclusion

The MSIS-29-Ar questionnaire is a valid and reliable outcome measure among Saudi patients with MS.

IMPLICATION FOR REHABILITATION

• Rehabilitation 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.

Keywords:

• Multiple sclerosis
• self-reported outcome measure
• health-related outcome measure
• psychometrics
• reliability
• Arabic population

Acknowledgments

The authors extend their appreciation to the Researchers Supporting Project number (RSPD2024R798), King Saud University, Riyadh, Saudi Arabia.

Disclosure statement

No potential conflict of interest was reported by the author(s).