Abstract
Multiple sclerosis (MS) is a chronic neurological condition that often results in language and communication difficulties, significantly affecting patients' quality of life. While several tools have been developed internationally to assess these impairments, few are validated for Arabic-speaking populations. This study aimed to translate, culturally adapt, and validate the Arabic version of the Communication and Language Assessment for Multiple Sclerosis (CALMS) questionnaire, designed to evaluate communication difficulties in individuals with MS. A cross-sectional study was conducted with 307 MS patients recruited from Al-Bashir Hospital in Amman, Jordan. Participants completed the Arabic CALMS (A-CALMS) via an online survey. Psychometric evaluation included Rasch analysis and Confirmatory Factor Analysis (CFA). Model fit, internal consistency (Cronbach's alpha), person/item reliability, threshold ordering, and Differential Item Functioning (DIF) by sex were assessed. The partial credit model (sign) provided a better fit than the rating scale model. After reordering, all threshold parameters were properly ordered, and item/person fit statistics were acceptable. Internal consistency was excellent (α = 0.935); CFA supported a one-factor solution with good model fit (χ2/df = 1.82, RMSEA = 0.052, CFI = 0.987, TLI = 0.984). No significant DIF was found across sexes. A moderate positive correlation was observed between CALMS and MSIS-29 scores (r = 0.534, p < .001), supporting construct validity. The A-CALMS demonstrated strong psychometric properties and cultural relevance, making it a reliable, valid instrument for assessing communication and language difficulties in Arabic-speaking individuals with MS. Its use in clinical and research settings may enhance diagnostic precision and inform tailored interventions.