Validating the Arabic MOS Pain Effects Scale for Adults With MS

PES-Ar, the Arabic version of the 6-item MOS Pain Effects Scale, has been validated for adults with multiple sclerosis in Saudi Arabia, showing strong test–retest reliability and a minimal detectable change at the 95% confidence level.

Cross-cultural adaptation was described as a stepwise process designed to preserve concepts rather than mirror wording. Two independent forward translations into Modern Standard Arabic (one medically trained, one non-medical) were reconciled into a single version, followed by two blinded back-translations and expert committee review to produce a pre-final instrument.

Cognitive debriefing and pilot testing in 20 people with MS used structured probing to confirm item comprehension, prompting minor edits to improve everyday fit without altering constructs. For pain-interference items, these refinements matter; rapid, consistent recognition of each life domain supports more stable scoring in routine use. Overall, the workflow indicates PES-Ar was adapted to protect item meaning and patient comprehension rather than translated word-for-word.

Content validity was assessed through expert ratings that translated qualitative judgments (clarity and relevance) into reproducible indices, using separate 4-point Likert scales for each dimension. The item-level content validity index (I-CVI) captured single-item agreement, and the scale-level content validity index (S-CVI) summarized endorsement across all six items. Using the authors’ interpretation framework, I-CVI and S-CVI were reported as excellent, supporting readiness for field administration in this population.