Electrophysiological and clinical correlation in myasthenia gravis

Abstract
Repetitive nerve stimulation testing of the ulnar nerve was systematically performed on 21 normal controls and 120 patients with myasthenia (MG). Diagnostic sensitivity increased from 0% in MG in remission and 17.2% in ocular MG to 100% in severe generalized MG. Six types of responses were observed in MG and could be classified into two distinct patterns based upon disease severity: (1) in mild MG, an abnormal decremental response at low rate of stimulation, normal response at high rate of stimulation, and prominent posttetanic facilitation and exhaustion phenomena; and (2) in severe MG, abnormal decremental responses at low as well as high stimulation rates and less common posttetanic facilitation and rare posttetanic exhaustion phenomena. This difference is most likely due to the severity of the neuromuscular block in MG.