Measurement Properties' Evaluation of the Arabic Version of the Patient-Specific Functional Scale in Patients with Multiple Sclerosis

Purpose: The aim of this study was to assess the reliability and validity of the Arabic version of the patient-specific functional scale (PSFS-Ar) in patients with multiple sclerosis (MS) disorder. Materials and Methods: Reliability and validity were examined in patients with multiple sclerosis using a longitudinal cohort study design. One hundred (N = 100) patients with MS were recruited to examine the PSFS-Ar, test-retest reliability (using the interclass correlation coefficient model 2,1 (ICC2,1)), construct validity (using the hypothesis testing method), and floor-ceiling effect. Results: A total of 100 participants completed the PSFS-Ar (34% male, 66% female). The PSFS-Ar showed an excellent test-retest reliability score (ICC2,1 = 0.87; 95% confidence interval, 0.75-0.93). The SEM of the PSFS-Ar was 0.80, while the MDC95 was 1.87, indicating an acceptable measurement error. The construct validity of the PSFS-Ar was 100% correlated with the predefined hypotheses. As hypothesized, the correlation analysis revealed positive correlations between the PSFS-Ar and the RAND-36 domains of physical functioning (0.5), role limitations due to physical health problems (0.37), energy/fatigue (0.35), and emotional well-being (0.19). There was no floor or ceiling effect in this study. Conclusions: The study results showed that the PSFS-Ar is a self-reported outcome measure that is useful for detecting specific functional difficulties in patients with multiple sclerosis. Patients are able to express and report a variety of functional limitations easily and effectively, as well as to measure their response to physical therapy. The PSFS-Ar is, therefore, recommended for use in Arabic-speaking countries for clinical practice and research for patients with multiple sclerosis.

Automated summary

The purpose of this study was to examine the reliability and validity of the Arabic version of the patient-specific functional scale (PSFS-Ar) in patients with multiple sclerosis. A longitudinal cohort study design was used to assess reliability and validity in 100 participants with MS. The PSFS-Ar demonstrated excellent test-retest reliability and acceptable measurement error, and was positively correlated with predefined hypotheses.