Fig. 1

Neurophysiological examinations. a Compound muscle action potential (CMAP) of the left abductor digiti minimi muscle (8.4 mV). b Significant increment (16.2 mV) following tetanic stimulation. c 43% decrement under 3 Hz repetitive stimulation of the left anconeus muscle. d 19% decrement of the right trapezius muscle (at first visit only)