Aim: To assess changes in motor function in patients with Duchenne muscular dystrophy using the Motor Function Measure (MFM).
Method: Three studies were performed. Two studies included only physiotherapy-treated patients, with 13 patients (males mean age 11y 7mo, SD 1y 10mo, range 8-14y) in the 3-month study and 41 patients (males mean age 14y 1mo, SD 5y 5mo, range 6-32y) in the 1-year study. A third study compared 12 patients treated with steroids with 12 age- and motor-function-matched untreated patients (males mean age of treated patients 10y 2mo, SD 2y 2mo range 6-14) over a 12-month period.
Results: Over 3 months, the MFM D1 subscore (standing and transfers) decreased significantly (-4.7%; p<0.01). Over 1 year, all MFM subscores decreased significantly: -4.9% for D1 (p<0.01); -7.7% for D2 (axial and proximal motor capacity; p<0.01); -4.3% for D3 (distal motor capacity; p=0.03); and -5.8% for the total score (p<0.01). A threshold value for loss of ambulation and a predictive value 1 year before loss were estimated (total score 70% and D1 subscore 40%). Compared with the controls, patients treated with steroids had more stable total scores (-0.59 vs -5.87; p=0.02) and D2 subscores (0.98 vs -8.50; p<0.01).
Interpretation: These results support the use of the MFM in everyday patient management to prepare for loss of ambulation and in clinical trials to follow up patients receiving various treatments.