Responsiveness and Validation Study of MFM-20 in SMA Patients Treated With Nusinersen

The Motor Function Measure (MFM), a reliable tool assessing motor function and its progression in most neuromuscular diseases, is widely used in France in many teams. It can be used regardless of the severity of the motor impairment or the ambulatory status of the patient, allowing its use throughout the whole follow-up period of the patient, even in case of the loss of walking. Two versions of the MFM exist, one composed of 32 items validated for patients from 6 years old (MFM-32) and a shorter version composed of 20 items validated for patients between 2 and 6 years old (MFM-20). In order to show the possible use of MFM-20 as early as the age of 2 years to validly and reliably monitor the evolution of the motor function of children treated with Nusinersen, we propose in this project to study the sensitivity to treatment-induced change of MFM-20 and the validity of the scale in this population.