SINGLE-FIBER ELECTROMYOGRAPHY OF EXTRAOCULAR-MUSCLES - A SENSITIVE METHOD FOR THE DIAGNOSIS OF OCULAR MYASTHENIA-GRAVIS

We performed single fiber electromyography (SFEMG) in the superior rec tus and levator palpebralis (SR-LP) muscles of 17 patients with pure o cular myasthenia gravis (MG) and 9 controls. Thirteen patients were al so assessed with SFEMG in the orbicularis oculi (OO) muscle. All the M G patients but none of the control subjects showed abnormal SFEMG jitt er in the SR-LP muscles. On the other hand, only 62% of the MG patient s had abnormal SFEMG jitter in the OO muscle. The procedure was well t olerated by the patients, and complications were minor. We conclude th at SFEMG of the SR-LP muscles is a safe and highly sensitive technique for the diagnosis of ocular MG. (C) 1995 John Wiley and Sons, Inc.