Simulation Techniques in Electromyography

A motor unit action potential (MUAP) recorded in clinical electromyography (EMG) is the spatial and temporal summation of the action potentials (AP's) from all muscle fibers in a motor unit (MU). An important determinant of MUAP waveform characteristics is the size of the recording electrode. In this paper, we have described the use of a modified line source model of single muscle fiber action potentials to simulate MUAP's as recorded by single fiber (SF) EMG, concentric needle (CN) EMG, and macro-EMG electrodes. Results indicate that SFEMG recordings from a normal MU contain mainly the AP's of the closest one to three muscle fibers of the MU. The amplitude, area, and duration of the simulated CNEMG MUAP's are determined mainly by the number and size of muscle fibers within a semicircular territory of 0.5, 1.5, and 2.5 mm, respectively, around the tip of the electrode. The amplitude and area of simulated macro-EMG MUAP's increase with the number of muscle fibers in the MU.

[1]  E Stålberg,et al.  Macro EMG in healthy subjects of different ages. , 1982, Journal of neurology, neurosurgery, and psychiatry.

[2]  P. Lawrence,et al.  On Modeling the Single Motor Unit Action Potential , 1978, IEEE Transactions on Biomedical Engineering.

[3]  E Stålberg,et al.  Simulation of macro EMG motor unit potentials. , 1983, Electroencephalography and clinical neurophysiology.

[4]  P. Rosenfalck.  Intra- and extracellular potential fields of active nerve and muscle fibres. A physico-mathematical analysis of different models. , 1969, Acta physiologica Scandinavica. Supplementum.

[5]  J Ekstedt,et al.  How the size of the needle electrode leading-off surface influences the shape of the single muscle fibre action potential in electromyography. , 1973, Computer programs in biomedicine.

[6]  C. Håkansson.  Conduction velocity and amplitude of the action potential as related to circumference in the isolated fibre of frog muscle. , 1956, Acta physiologica Scandinavica.

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

[8]  Håkan Askmark,et al.  Topographical localization of motor endplates in cryosections of whole human muscles , 1984, Muscle & nerve.

[9]  V. Dubowitz,et al.  Muscle biopsy: A modern approach , 1973 .

[10]  F Buchthal,et al.  Diagnostic yield of the analysis of the pattern of electrical activity of muscle and of individual motor unit potentials in neurogenic involvement. , 1977, Journal of neurology, neurosurgery, and psychiatry.

[11]  F. Buchthal,et al.  Motor unit territory in different human muscles. , 1959, Acta physiologica Scandinavica.

[12]  E Stålberg,et al.  Motor unit size in muscular dystrophy, a macro EMG and scanning EMG study. , 1983, Journal of neurology, neurosurgery, and psychiatry.

[13]  R PLONSEY,et al.  VOLUME CONDUCTOR FIELDS OF ACTION CURRENTS. , 1964, Biophysical journal.

[14]  H B Boom,et al.  Calculation and registration of the same motor unit action potential. , 1982, Electroencephalography and clinical neurophysiology.

[15]  E Stålberg,et al.  Macro EMG, a new recording technique. , 1980, Journal of neurology, neurosurgery, and psychiatry.

[16]  E CHRISTENSEN,et al.  TOPOGRAPHY OF TERMINAL MOTOR INNERVATION IN STRIATED MUSCLES FROM STILLBORN INFANTS , 1959, American journal of physical medicine.

[17]  E Stålberg,et al.  The motor unit in muscular dystrophy, a single fibre EMG and scanning EMG study. , 1983, Journal of neurology, neurosurgery, and psychiatry.

[18]  L Antoni,et al.  Electrophysiological cross section of the motor unit. , 1980, Journal of neurology, neurosurgery, and psychiatry.

[19]  S. Andreassen,et al.  Relationship of intracellular and extracellular action potentials of skeletal muscle fibers. , 1981, Critical reviews in bioengineering.

[20]  E Stalberg,et al.  Propagation velocity in human muscle fibers in situ. , 1966, Acta physiologica Scandinavica. Supplementum.

[21]  F Buchthal,et al.  Diagnostic yield of analysis of the pattern of electrical activity and of individual motor unit potentials in myopathy. , 1976, Journal of neurology, neurosurgery, and psychiatry.

[22]  F BUCHTHAL,et al.  ACTION POTENTIAL PARAMETERS IN DIFFERENT HUMAN MUSCLES , 1955, Acta psychiatrica et neurologica Scandinavica.

[23]  C. Sherrington.  Ferrier lecture.—Some functional problems attaching to convergence , 1929 .