Translation, cross-cultural adaptation, validation, reliability, and reproducibility of the arm function in multiple sclerosis questionnaire (AMSQ) for upper limb function assessment in individuals with multiple sclerosis in Brazilian Portuguese

INTRODUCTION: Multiple Sclerosis (MS) is a chronic neurological condition that frequently compromises upper limb (UL) function. Despite its functional relevance, few instruments validated in Brazilian Portuguese are specific to this population. The Arm Function in Multiple Sclerosis Questionnaire (AMSQ) was originally developed in Dutch to measure this function in individuals with MS. OBJECTIVE: To translate, cross-culturally adapt, and validate the AMSQ for Brazilian Portuguese. METHODS: The study was approved by the HCPA Research Ethics Committee (CAAE: 82069424.0.0000.5327) and followed international guidelines, including translation, synthesis, back-translation, content validation and reliability. The Content Validity Index (CVI) was calculated. In the reliability stage, 50 individuals with MS answered the AMSQ at two time points, with an interval of 3-5 days. Internal consistency was assessed using Cronbach's alpha, and test-retest reproducibility was evaluated by the Intraclass Correlation Coefficient (ICC 2,1). RESULTS: The questionnaire was well understood by the participants, confirming its cultural appropriateness. The AMSQ-BR showed a CVI above 90% for all items and presented excellent reproducibility (ICC = 0.932) and internal consistency (α = 0.984). CONCLUSION: The Brazilian version of the AMSQ-BR is valid and reliable for the assessment of upper limb function in individuals with multiple sclerosis. It presents content validity, test-retest reproducibility, and internal consistency, making it a relevant tool for clinical and research use in the Brazilian context.