Macro EMG.

A new EMG recording technique called macro EMG is described. The recording electrode is the cannula of the modified single fiber electromyography (SFEMG) electrode. By means of spike triggered averaging, the contribution from all muscle fibers in a motor unit is extracted. The resulting signal reflects the number and size of muscle fibers in one motor unit. This paper presents the details of the technique, the neurophysiological basis for generation of the macro EMG signal, and the typical findings in normal and diseased muscles. Finally, examples are given of the additional information that can be obtained by combining investigations with SFEMG, conventional EMG, and macro EMG in the same muscles.