A TRIAL OF GRADING MYOPATHY BY EMG ANALYSIS AND ITS CLINICAL USE

Electromyography has been one of the most important ways of diagnosing myopathy. Especially analysis of EMG can yield quantitative informations for its diagnosis. Automatic frequency analysis and wave integration have been in clinical use in our daily outpatient clinic. EMG recording of 32 myopathy cases were reviewed and 12 healthy subjects were examined. EMG was classified in to 4 types according to its grading by the combination of automatic frequency spectrogram and a value of wave integration. Four types were graded normal, slight moderate, and advanced. This grading of myopathy was useful to follow a course of muscle disease which changed its severity by treatment such as thyrotoxic myopathy, while in such a disease as Duchenne muscular dystrophy, EMG analysis already showed advanced grading at the time when clinical diagnosis became apparent. In these cases application of EMG grading to subclinical stage might be suitable.