Electromyographic findings in the so-called non-progressive myopathies

Electrophysiological findings in 40 cases of non-progressive myopathies are reported, and compared with a group of 20 cases of Duchenne progressive muscular dystrophy and a control group. In all cases the electrophysiological changes were of the mild s. c. myogenic type. The involvement of proximal and distal muscles was equal without prevalence in proximal muscles as is typical for Duchenne's dystrophy. EMG reexaminations showed a slight progression of the diseases. A peculiar feature of myotubular myopathy was spontaneous activity (fibrillation) in 70% of muscles. A myogenic character of the process of congenital deficiency of muscle innervation with preserved number of motor units is suggested.