Quantitative Analysis of Electromyography

J Korean Assoc EMG Electrodiagn Med 2000;2(2):69-78.
Published online May 10, 2000.

Abstract

Electromyographic investigation is performed with the muscle at rest, during slight contraction, and during strong contraction. The last two steps can now be performed quantitatively with high speed; the results are reproducible and allow quantitative comparisons with follow-up studies. Thus, the knowledge and technique of quantitative analysis of EMG can easily be incorporated within the routine EMG examination to recognize and document EMG abnormalities. The configurational and behavioral properties of single motor unit action potential (MUAP) can be measured by the traditional MUAP analysis at weak contraction and decomposition of interference pattern into their constituent MUAPs. Interference pattern (IP) analysis also contains information about features of MUAP and number of active motor units and their individual firing rates. The electromyographer should use their individual, unique features in a logical way and focus the analysis on the parameters that provide optimal information in each situation. The major application of quantitative EMG is patients with known or suspected generalized neuromuscular disorders by providing accurate diagnosis and natural progression or response to treatment of the disorder for serial reexamination.

Key Words: Quantitative electromyography, Motor unit action potential, Interference pattern