Translation, cross-cultural adaptation, and psychometric properties of the Arabic version of the Rivermead Mobility Index (RMI) scale for patients with multiple sclerosis.

Abstract

The Rivermead mobility index (RMI) is a patient self-reported outcome (PRO) that measures patients' mobility. This study aimed to translate and cross-culturally adapt the (RMI) into Arabic and to assess its validity and psychometric properties. RMI was translated into Arabic in accordance with international consensus guidelines. Using a cross-sectional design, one hundred patients with Multiple Sclerosis completed the Arabic version of the Rivermead Mobility Index (RMI-Ar), the Barthel Index (BI), and the Multiple Sclerosis Impact Scale-29 (MSIS-29), which includes two subscales for the physical (PHYS) and psychological (PSYCH). To assess test-retest reliability, fifty participants were asked to retake the RMI-Ar after a two-week interval. The RMI-Ar was simple and understandable to patients with MS in Saudi Arabia. The internal consistency of the RMI-Ar was excellent (Cronbach's alpha = 0.908), and test-retest reliability was strong (ICC = 0.908). The minimal detectable change between the test and retest was 26.8% for RMI. Additionally, the RMI-Ar demonstrated good face and content validity, confirming that all items were relevant, clear, and concise, as well as construct validity, shown by strong positive correlations with the Barthel Index (rho = 0.73) and weak negative correlations with the MSIS-29 psychological domain (rho = -0.23). No floor or ceiling effect was observed, affirming the scale's capacity to differentiate between participation levels. The RMI-Ar questionnaire is a valid and reliable outcome measure to use in clinical and research settings.