Farshad Molhemi, Narjes Saadi, Razieh Mofateh, Narges Shakerian, Ludovico Pedullà, Saeideh Monjezi
Background Assessing dual-task (DT) difficulties during activities of daily living is of substantial importance in people with multiple sclerosis (PwMS). The Dual-task Impact on Daily-living Activities Questionnaire (DIDA-Q) is a recently developed patient-reported outcome measures designed to assess the perceived DT difficulties. The purpose of this study was to translate and culturally adapt the DIDA-Q into Persian and to examine its validity and reliability in Iranian PwMS.Methods Sixty-nine PwMS participated in this cross-sectional study. During the initial session, participants completed the Persian DIDA-Q, Arm Function in Multiple Sclerosis Questionnaire (AMSQ), and DT performance assessments including the Nine-Hole Peg Test (NHPT) and Timed Up and Go (TUG) with cognitive or motor secondary tasks. To assess test – retest reliability, the Persian DIDA-Q was re-administered one week later. Construct validity was examined using correlation analysis, while reliability was assessed through internal consistency and test – retest reliability. The standard error of measurement (SEM) and minimal detectable change (MDC95) were also calculated.Results No ceiling or floor effects were observed for the Persian DIDA-Q. Construct validity was supported by significant moderate-to-strong correlations between the DIDA-Q and the AMSQ, as well as objective DT performance on the NHPT and TUG tests (r = 0.31–0.69, p < .05). The Persian DIDA-Q showed excellent test – retest reliability (Intraclass Correlation Coefficient3,1 = 0.98) and high internal consistency (Cronbach’s α = 0.94). The SEM and MDC95 were 2.08 and 6 points, respectively.Conclusion The Persian DIDA-Q provides a clinically interpretable and culturally adapted tool for identifying and monitoring perceived DT difficulties in Persian-speaking PwMS, thereby supporting both clinical assessment and future rehabilitation research.