Techniques for Improving the Selectivity of Electromyographic Recordings

Several methods aimed at obtaining highly selective electromyographic recordings are studied in human muscle with a multi-electrode technique. It was found that a small electrode size had a major effect in obtaining selective recording. High-pass filtering of the signal resulted in a further increase in the amplitude ratio of action potentials generated by close and remote fibers due to different frequency content of the action potentials. Additional improvement in selectivity could be achieved by bipolar recording.