Abstract
Automatic decomposition electromyography (ADEMG) is a commercially available software package with installed reference values that enables the objective measurement of motor unit action potentials (MUAPs). To assess the diagnostic yield of this package in idiopathic inflammatory myopathies (IIM) we performed biceps brachii ADEMG in 17 patients with polymyositis, dermatomyositis and inclusion body myositis. Results were compared with those in 12 controls, and with the results of conventional EMG of the biceps and other muscles. Decreased mean values for MUAP duration occurred significantly more frequently in IIM patients than in controls; other MUAP characteristics did not differ. In IIM patients, decreased mean amplitude and increased mean number of turns occurred significantly less frequently on ADEMG than did corresponding abnormalities on conventional biceps EMG. Decreased mean values for duration and amplitude, and increased mean values for number of turns were seen significantly less often on ADEMG than corresponding abnormalities on conventional EMG of four different, individually chosen muscles. Overall evaluation of ADEMG resulted in a diagnosis of “possible myopathy” in 1 and “probable myopathy” in 8 patients, whereas overall evaluation of conventional EMG led to a diagnosis “suggestive of IIM” in 13 patients. We conclude that, although measurement of mean MUAP duration might be valuable in IIM diagnosis, our results do not favour the use of biceps brachii ADEMG and the installed reference values for the diagnosis of IIM. We suggest modifications to improve ADEMG's applicability.
Similar content being viewed by others
References
Buchthal F (1958) Einfuehrung in die Elektromyographie. Urban & Schwarzenberg, Munich, p 34
Chan RC, Hsu TC (1992) Motor unit potential analysis under submaximal contraction: ADEMG study in normal and radiculopathy (English abstract). Chung Hua I Hsueh Tsa Chin 50:19–25
Dalakas MC (1991) Polymyositis, dermatomyositis, and inclusion-body myositis. N Engl J Med 325:1487–1498
Daube JR (1991) AAEE Minimonograph no. 11: Needle examination in clinical electromyography. Muscle Nerve 14:685–700
Dorfman LJ, McGill KC (1988) AAEE Minimonograph no.29: Automatic quantitative electromyography. Muscle Nerve 11:804–818
Dorfman LJ, Howard JE, McGill KC (1989) Motor unit firing rates and firing rate variability in the detection of neuromuscular disorders. Electroencephalogr Clin Neurophysiol 73:215–224
Dorfman LJ, Howard JE, McGill KC (1989) Clinical studies using automatic decomposition electromyography (ADEMG) in needle and surface EMG. In: Desmedt JE (ed) Computer-aided electromyography and expert-systems. Elsevier, The Hague, pp 198–204
Falck B, Andreassen S, Groth T, Lang H, Melander M, Nurmi A, Puusa A, Rosenfalck A, Stalberg E (1991) The development of a multicenter database for reference values in clinical neurophysiology — principles and examples. Computer Methods Programs Biomed 34:145–162
Fuglsang-Frederiksen A (1987) Quantitative electromyography. I. Comparison of different methods. Electromyogr Clin Neurophysiol 27:327–333
Hausmanowa-Petrusewicz I, Rowinska-Marcinska K, Emeryk-Szajewska B, Ryniewicz B, Kopec A, Kopec J, Szmidt-Salkowska E (1988) The diagnostic yield of automated EMG analysis in neuromuscular diseases. Acta Physiol Pol 39:11–19
Howard JE, McGill KC, Dorfman LJ (1988) Properties of motor unit action potentials recorded with concentric and monopolar needle electrodes: ADEMG analysis. Muscle Nerve 11:1051–1055
Iani C, Stalberg E, Falck B, Bishoff C (1994) New approaches to motor unit potential analysis. Proceedings of the Comprehensive EMG Congress, 26–29 April 1994, Uppsala, chapter 14
Kimura J (1989) Electrodiagnosis in diseases of nerve and muscle. Davis, Philadelphia
McGill KC, Dorfman LJ (1989) Automatic decomposition electromyography (ADEMG). Methodological and technical considerations. In: Desmedt JE (ed) Computer-aided electromyography and expert-systems. Elsevier, The Hague, pp 91–101
McGill KC, Cummins KL, Dorfman LJ (1985) Automatic decomposition of the clinic electromyogram. IEEE Trans Biol Eng BME-32:470–477
Nandedkar SD, Sanders DB, Stalberg EV (1986) Automatic analysis of the electromyographic interference pattern. II. Findings in control subjects and in some neuromuscular disorders. Muscle Nerve 9:491–500
Robinson LR (1991) AAEE Case report no.22: Polymyositis. Muscle Nerve 14:310–315
Sandstedt PER, Henriksson KG, Larsson L-E (1982) Quantitative electromyography in polymyositis and dermatomyositis, a long-term study. Acta Neurol Scand 65:110–121
Stalberg E, Andreassen S, Falck B, Lang H, Rosenfalck A, Trojaborg W (1986) Quantitative analysis of individual motor unit potentials: a proposition for standardized terminology and criteria for measurement. J Clinical Neurophysiol 3:313–348
Walton J (1988) Inflammatory disorders of muscle: clinical features and differential diagnosis. In: Mastaglia FL (ed) Inflammatory diseases of muscle. Blackwell, Oxford, pp 1–16
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Jongen, P.J.H., Vingerhoets, H.M., Roeleveld, K. et al. Automatic decomposition electromyography in idiopathic inflammatory myopathies. J Neurol 243, 79–85 (1996). https://doi.org/10.1007/BF00878536
Received:
Revised:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00878536