An electrophysiological investigation of limb-girdle and facioscapulohumeral dystrophy

A detailed electrophysiological study has been made of the extensor digitorum brevis muscle and its motor innervation in 11 patients with limb-girdle or facioscapulohumeral dystrophy. In nine patients there were reductions in the populations of motor units and many surviving units appeared to be abnormally large. Most of the investigated muscles had slowed isometric twitches and decremental evoked potentials after repetitive nerve stimulation. The experimental observations have been interpreted in terms of a neuropathic process.