The motor function measure (MFM) in the facio scapulo humeral dystrophy (FSHD) population: Description and responsiveness

Abstract

To assess the applicability and the responsiveness of the motor function measure 1 (MFM) in a facio scapulo humeral dystrophy (FSHD) population. It is an observational, retrospective and multicenter, cohort study. MFM data came from the MFM database (see http://www.motor-function-measure.org/data-bank.aspx ). Only FSHD patients with at least one MFM-32 were included. The distributions of the MFM scores (total score and MFM D1, D2 and D3 subscores) were analyzed by age. MFM responsiveness was estimated in patients with at least two MFMs (at least six months between the two evaluations). Hypothetical sample sizes for specific effect sizes in clinical trial scenarios are given. The descriptive study includes 269 patients aged 6.1–82.8 years (145 males/124 females) from 26 physical medicine and rehabilitation or neurology departments. 467 MFM-32 for FSHD patients are registered in the MFM database and 117 patients have a least two evaluations registered. 393 MFM were realized in adults’ patients (> 18 years old). Mean age of first signs was 24.5 years ± 15.9 (available for 124 patients). MFM D1 subscore (standing and transfers) is the more sensitive score to show deterioration (–2.75 points + –4.3/year). MFM D2 (proximal and axial motricity) and D3 (distal motricity) subscores showed less changes over time (–0.98 + –3.27 points/year for D2, –0.81 + –4.07 points/year for D3). Significant responsiveness was obtained with the D1 subscore (standardized response mean [SRM] = 0.640). MFM scale and particular D1 subscore is a reliable and valid outcome measure to applied in longitudinal follow-up and in clinical trials address to FSHD population.