Italian translation and psychometric validation of the Manual Ability Measure-36 (MAM-36) and its correlation with an objective measure of upper limb function in patients with multiple sclerosis

Background: Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system with an unpredictable course. During its course, deficits affecting upper limb functions may occur. Hence, there is a need for self-administered scales providing a comprehensive assessment of upper limb functions. The Manual Ability Measure-36 (MAM-36), which investigates patients’ performance in activities of daily living requiring upper limb function, has not been adapted and validated in the Italian context. Objectives: We develop an Italian translation and validation of the MAM-36 in a population of people with MS (PwMS), explore its psychometric properties and investigate its associations with clinical data and the Nine Hole Peg Test (9-HPT). Research plan and methods: The multicentre study involved five Italian neurological centres. Subjects were evaluated using EDSS, 9-HPT and the MAM-36 scale. We used confirmatory factor analysis and Rasch analysis to investigate the properties of the MAM-36. Results: We enrolled 218 PwMS. Results supported the unidimensionality of the MAM-36, and adequate functioning of rating scale and items. Additionally, the MAM-36 showed weak negative associations with age and disease duration, and moderate associations with EDSS and 9-HPT scores. Discussion: The adapted MAM-36 showed adequate psychometric properties. However, indications of problematic targeting to PwMS with low disability emerged. For this reason, use of the scale appears to be more suitable among patients with moderate-to-severe disability.