Simulation and analysis of the electromyographic interference pattern in normal muscle. Part I: Turns and amplitude measurements

The electromyographic (EMG) interference pattern (IP) was simulated by adding together motor unit action potentials (MUAPs) of different sizes that had been recorded by a concentric needle EMG electrode. The number of turns (NT) of the simulated IP increased with the number of MUAP discharges. The mean amplitude (MA) difference between successive turns in the IP increased when large amplitude MUAPs were added. Our analysis demonstrates that the MA of the IP is determined mainly by the amplitude of large MUAPs in the signal and that large amplitude spikes are more likely to be generated by single large amplitude MUAPs than by summation of several small amplitude MUAPs.

[1]  H P Clamann,et al.  Activity of single motor units during isometric tension , 1970, Neurology.

[2]  E Stålberg,et al.  Automatic analysis of the EMG interference pattern. , 1983, Electroencephalography and clinical neurophysiology.

[3]  R. Willison,et al.  Analysis of electrical activity in healthy and dystrophic muscle in man , 1964, Journal of neurology, neurosurgery, and psychiatry.

[4]  R B Stein,et al.  The orderly recruitment of human motor units during voluntary isometric contractions , 1973, The Journal of physiology.

[5]  R. Stein,et al.  Changes in firing rate of human motor units during linearly changing voluntary contractions , 1973, The Journal of physiology.

[6]  Isak Gath,et al.  Measurements of the Uptake Area of Small-Size Electromyographic Electrodes , 1979, IEEE Transactions on Biomedical Engineering.

[7]  A. Fuglsang-Frederiksen,et al.  Analysis of electrical activity of normal muscle in man at different degrees of voluntary effort. , 1975, Journal of neurology, neurosurgery, and psychiatry.