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The analysis of the firing intervals of motor units has been suggested as a diagnostic tool in patients with neuromuscular disorders. Part of the increase in number of turns seen in patients with myopathy could be secondary to the decrease in motor unit firing intervals at threshold force of the motor units, as noted in previous studies. In the brachial biceps muscle we have studied the firing intervals of 164 motor units in 14 controls, 140 motor units in 13 patients with myopathy and 86 motor units in 8 patients with neurogenic disorders, and related the findings to those of the turns analysis and the analysis of properties of individual motor unit potentials. To ensure comparable conditions we have examined motor unit firing intervals and turns at a force of 10% of maximum. The average of motor unit firing intervals and of interval variability was the same in controls and in patients, and the diagnostic yield of the motor unit firing intervals analysis was none. Although the number of turns increased with decreasing motor unit firing intervals, this relation was physiological rather than pathophysiological. In patients with neurogenic disorders, interval variability indicated unstable firing in severely affected muscles.
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- Computerized analysis of motor unit firing.in: Desmedt J.E. Computer-aided Electromyography. Progress in Clinical Neurophysiology. Vol. 10. Karger, Basel1983: 150-163
- An Introduction to Electromyography.in: Gyldendal, Copenhagen1957: 43
- Statistical analysis of motor unit firing patterns in a human skeletal muscle.Biophys. J. 1969; 9: 1233-1251
- Discharge characteristics of single motor fibres of hand muscles in lower motoneurone diseases and myopathies.in: Kunze K. Desmedt J.E. Studies on Neuromuscular Diseases. Karger, Basel1975: 122-127
- An analyser for use in human electromyography.Electron. Engng. 1967; 39: 240-243
- Electrical activity and force during voluntary contraction of normal and diseased muscle.Acta Neurol. Scand. 1981; 63: 1-60
- Analysis of electrical activity of normal muscle in man at different degrees of voluntary effort.J. Neurol. Neurosurg. Psychiat. 1975; 38: 683-694
- Diagnostic yield of analysis of the pattern of electrical activity and of individual motor unit potentials in myopathy.J. Neurol. Neurosurg. Psychiat. 1976; 39: 742-750
- The firing rate of motor units in neuromuscular disorders.J. Neurol. 1981; 225: 269-276
- Firing rates of human motor units in partially denervated muscle.Neurology. 1978; 28: 1241-1248
- Clinical electromyographic studies of diseases of the motor unit.Electroenceph. Clin. Neurophysiol. 1974; 36: 395-401
- Quantitative electromyography using automatic analysis: studies in healthy subjects and patients with primary muscle disease.J. Neurol. Neurosurg. Psychiat. 1967; 30: 403-410
- The behavior of motor units in healthy and paretic muscles in man.Acta Psychiat. Scand. 1941; 16: 79-109
- The behavior of motor units in healthy and paretic muscles in man.Acta Psychiat. Scand. 1941; 16: 261-278
- Analysis of electrical activity in dystrophic muscle in man.J. Neurol. Neurosurg. Psychiat. 1964; 27: 386-394
Accepted: September 12, 1986
Received in revised form: September 11, 1986
Received: June 10, 1986
☆This work was supported by grants from the Danish Medical Research Council and the Danish Muscular Dystrophy Association.
© 1987 Published by Elsevier Inc.