Diagnostic yield of stimulation and voluntary single-fiber electromyography in myasthenia gravis

Voluntary and stimulation single-fiber electromyography were performed in the extensor digitorum communis muscle of 15 myasthenic patients. The increase in mean and individual mean consecutive difference as well as the proportion of blocking in the volitional activation were greater than in the stimulation method. These differences may be explained in part by the different degree of alteration in large as compared with small motor units in patients with myasthenia gravis. © 1998 John Wiley & Sons, Inc. Muscle Nerve 21:1081–1083, 1998.