Fifty-four quantitative electromyographic (EMG) studies were made in 37 patients with inflammatory myopathy (IM) at different points in their clinical course and tretment. All studies were performed in the biceps brachii which varied in clinical strength. Motor unit action potentials (MUAPs) in 45 studies and EMG interference pattern (IP) in 48 studies were recorded using a concentric needle electrode. Macroelectromyographic (Macro-EMG) MUAPs were recorded from 10 patients in 14 studies. MUAP analysis revealed a myopathic pattern (decreased duration and/or area: amplitude ratio) in 69% of studies. IP analysis was more sensitive than MUAP analysis, demonstrating a myopathic pattern in 83% of studies. Macro-EMG MUAP amplitudes were reduced in two studies, minimally increased in one study and normal in the remainder; in 6 (40%) studies, fiber density was slightly increased. Thus, reinnervation does not seem to play an important role in motor unit remodeling in IM.

References

1 Banker BQ, Engel AG: The polymyositis and dermatomyositis syndromes, in AG Engel, BQ Banker (eds): Myology. New York, McGraw Hill, 1986, vol 2, pp 1385–1422.
Google Scholar
2 Bohan A, Peter JB: Polymyositis and dermatomyositis. New Engl J Med 1975; 292: 344–347, 403–407.
10.1056/NEJM197502132920706
CAS PubMed Web of Science® Google Scholar
3 Buchthal F, Pinelli P: Muscle action potentials in polymyositis. Neurology 1953; 3: 424–436.
10.1212/WNL.3.6.424
CAS PubMed Web of Science® Google Scholar
4 Buchhal F: Diagnostic significance of the myopathic EMG, in LP Rowland (ed): Pathogenesis of Human Muscular Dystrophies. Amsterdam, Excerpta Medica, 1977, pp 205–218.
Google Scholar
5 Buchthal F: Electrophysiological signs of myopathy as related to muscle biopsy. Acta Neurol (Napoli) 1977; 32: 1–29.
CAS PubMed Google Scholar
6 Buchthal F, Kamieniecka Z: The diagnostic yield of quantified electromyography and quantified muscle biopsy in neuromuscular disorders. Muscle Nerve 1982; 5: 265–280.
10.1002/mus.880050403
CAS PubMed Web of Science® Google Scholar
7 Daube Jr: Electrodiagnosis of muscle disorders, in AG Engel, BQ Banker (eds): Myology. New York, McGraw-Hill, 1986, vol 1, pp 1081–1121.
Google Scholar
8 Dubowitz V, Brooke MH: Muscle Biopsy: A Practical Approach, 1st ed. London, Saunders, 1973, pp 319–321.
Google Scholar
9 Henriksson KG, Stålberg E: The terminal innervation pattern in polymyositis: a histochemical and SFEMG study. Muscle Nerve 1978; 1: 3–13.
10.1002/mus.880010103
CAS PubMed Web of Science® Google Scholar
10 Kimura J: Electrodiagnosis in Diseases of Nerve and Muscle: Principles and Practice. Philadelphia, Davis, 1983, pp 538–540.
Google Scholar
11 Nandedkar SD, Stålberg EV: Simulation of macro EMG motor unit action potentials. EEG Clin Neurophysiol 1983; 56: 52–62.
10.1016/0013-4694(83)90006-8
CAS PubMed Web of Science® Google Scholar
12 Nandedkar S, Sanders DB, Stålberg EV: Automatic analysis of the electromyographic interference pattern. Part I: Development of quantitative parameters. Muscle Nerve 1986; 9: 431–439.
10.1002/mus.880090508
CAS PubMed Web of Science® Google Scholar
13 Nandedkar S, Sanders DB, Stålberg EV: Automatic analysis of the electromyographic interference pattern. Part II: Findings in control subjects and in some neuromuscular diseases. Muscle Nerve 1986; 9: 491–500.
10.1002/mus.880090604
CAS PubMed Web of Science® Google Scholar
14 Nandedkar SD, Barkhaus PE, Sanders DB, Stålberg EV: Analysis of amplitude and area of concentric needle EMG motor unit action potentials. EEG Clin Neurophysiol 1988; 69: 561–567.
10.1016/0013-4694(88)90168-X
CAS PubMed Web of Science® Google Scholar
15 Nandedkar SD, Sanders DB, Stålberg EV: Andreasson S: Simulation of concentric needle EMG motor unit action potentials. Muscle Nerve, 1988; 11: 151–159.
10.1002/mus.880110211
CAS PubMed Web of Science® Google Scholar
16 Nandedkar SD, Sanders DB: Simulation of myopathic motor unit action potentials. Muscle Nerve, 1989; 12: 197–202.
10.1002/mus.880120306
CAS PubMed Web of Science® Google Scholar
17 Stålberg EV, Electrogenesis in human dystrophic muscle, in LP Rowland (ed): Pathogenesis of Human Muscular Dystrophies. Amsterdam, Excerpta Medica, 1977, pp 570–1982.
Google Scholar
18 Stålberg EV, Fawcett PRW: Macro EMG in healthy subjects of different ages. J Neurol Neurosurg Psychiatry 1982; 45: 870–878.
10.1136/jnnp.45.10.870
CAS PubMed Web of Science® Google Scholar
19 Stålberg EV: Macro EMG. Muscle Nerve 1983; 6: 619–630.
10.1002/mus.880060902
CAS PubMed Web of Science® Google Scholar
20 Stewart CR, Nandedkar SD, Massey JM, Gilchrist JM, Barkhaus PE, Sanders DB: Evaluation of an automatic method of measuring features of motor unit action potentials. Muscle Nerve, 1989; 12: 141–148.
10.1002/mus.880120209
CAS PubMed Web of Science® Google Scholar
21 Trojaborg W: Motor unit disorder and myopathies, in AM Halliday, SR Butler, R Paul (eds): A Textbook of Clinical Neurophysiology. New York, John Wiley & Sons, 1987, pp 417–437.
Google Scholar

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Volume13, Issue3

March 1990

Pages 247-253

Quantitative EMG in inflammatory myopathy

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