Responsiveness of the motor function measure in neuromuscular diseases

International audience; OBJECTIVES: To study the responsiveness (sensitivity to change) of the Motor Function Measure (MFM) in detecting change in neuromuscular disease patients with the intent of using this measure in future clinical trials. DESIGN: Prospective cohort observational study. SETTING: Inpatient and outpatient facilities for follow-up and treatment of neuromuscular diseases. PARTICIPANTS: Patients (N=152) with various neuromuscular diseases aged 6 to 60 years. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE(S): We used the MFM total score and its 3 subscores on 2 measurements grossly 1 year apart. The physicians and the patients (or proxy) were asked to provide their perceived change in functional status since the first MFM. These changes were expressed in 3 outcomes: deterioration, stability, or improvement. RESULTS: The overall 12-month-standardized mean change of the total score mean ± SD annual total score change was -2.4±5.5 points (P