Proposal of a new clinical protocol for evaluating fatigability in adult SMA patients

Objective: Spinal Muscular Atrophy (SMA) is a genetic neuromuscular disease affecting the lower motor neuron, carrying a significant burden on patients' general motor skills and quality of life, characterized by a great variability in phenotypic expression. As new therapeutic options make their appearance on the scene, sensitive clinical tools and outcome measures are needed, especially in adult patients undergoing treatment, in which the expected clinical response is a mild improvement or stabilization of disease progression. Methods: Here, we describe a new functional motor scale specifically designed for evaluating the endurance dimension for the upper and lower limbs in adult SMA patients. Results: The scale was first tested in eight control healthy subjects and then validated in ten adult SMA patients, proving intra- and inter-observer reliability. We also set up an evaluation protocol by using wearable devices including surface EMG and accelerometer. Conclusions: The endurance evaluation should integrate the standard clinical monitoring in the management and follow-up of SMA adult patients.