[Facilitation phenomenon in electrophysiological diagnosis of myasthenia gravis]

A group of 10 patients with atypical result of repetitive stimulation was selected out of the patients examined in our EMG Laboratory. The diagnosis of myasthenia was clinically confirmed. In all those 10 patients no essential amplitude decrement was found on stimulation, so the electrophysiological confirmation of the diagnosis was lacking. On repetitive stimulation (3 Hz) all increment of the response was observed and also post-tetanic facilitation was present. In SFEMG moderate neuromuscular transmission disturbances were found in those patients. It suggests that, sometimes, facilitation may reflect disturbed neuromuscular transmission even despite the absence of the typical amplitude decrement.