Muscle biopsy correlated with electromyography: study of 100 cases

Werneck, Lineu Cesar; Lima, José Geraldo Camargo

doi:10.1590/S0004-282X1988000200006

Abstracts

To find what the correlation is and verify if is possible to avoid extensive electromyographic examination, studying only one muscle, 100 patients with neuromuscular disorders (58 primary myopathies, 32 neurogenic disorders and 10 myotonic dystrophies) were submited to quantified electromyography (EMG) and muscle biopsy (MB) with fresh-frozen section plus histochemistry in the same muscle, but on the opposite side. The EMG was abnormal in 98% and MB in 93% of the cases. EMG and MB had a concordance of 84.3% in the neurogenic disorders and 84.77% in the primary myopathies. A correlation of 80% was obtained between all MB and EMG (including the cases of myotonic dystrophies), regarding the origin of the pathogenic process (p<0.01). The EMG had 5% inconsistences and the MB 11%, with respect to the pathogenic process. When the myotonic dystrophy was separated from the primary myopathies and from the denervation disorders, a complete concordance was found in all MB and had only 3.4% inconsistences in the denervation disorders and 3.1% in the primary myopathies.

A fim de verificar qual a correlação entre uma biópsia muscular e a eletromiografia quando um único músculo é estudado, bem como verificar a possibilidade de evitar eletromiografias extensivas e dolorosas em determinadas doenças, foram investigados 100 pacientes com doenças neuromusculares (58 com miopatias primárias, 32 doenças que determinam desinervação e 10 distrofias miotônicas). Todos os casos foram submetidos a eletromiografia quantificada (EMG) e a biópsia muscular (BM), utilizando técnicas de colorações a fresco e pela histoquímica, realizadas no mesmo músculo, mas em lados opostos do paciente. A EMG foi anormal em 98% e a BM in 93% dos casos. A EMG e a BM tiveram concordância de 84,3% nas doenças neurogênicas e 84,77% nas miopatias primárias. Foi obtida correlação de 80% entre a EMG e a BM em todos os casos, com relação à patogenia do processo (p<0,01). A EMG teve 5% de inconsistências e a BM 11%, em relação ao diagnóstico patogênico. Quando a distrofia miotônica foi separada das miopatias primárias e dos processos que determinam desinervação, uma concordância completa foi encontrada entre todas as BM e a EMG mostrou inconsistências somente em 3,4% das doenças que determinam desinervação e 3,1% das miopatias primárias, sugerindo que a distrofia miotônica deva ser classificada em um grupo separado (neuromiopatias). Os autores discutem os dados encontrados em relação à literatura existente e concluem que, dependendo da avaliação clínica, é possível submeter os pacientes a somente um dos procedimentos (geralmente a BM), utilizando ambos os procedimentos somente nos casos em que não foi possível chegar a um diagnóstico, sendo então examinados diversos músculos na EMG.

Lineu Cesar Werneck^I; José Geraldo Camargo Lima^II

^IProfessor Adjunto Neurologia, UFPR - Division of Neurology, Internai Medicine Department, Universidade Federal do Paraná (UFPR) and Neurology Department, Escola Paulista de Medicina (EPM)

^IIProfessor Titular Neurologia, EPM - Division of Neurology, Internai Medicine Department, Universidade Federal do Paraná (UFPR) and Neurology Department, Escola Paulista de Medicina (EPM)

SUMMARY

To find what the correlation is and verify if is possible to avoid extensive electromyographic examination, studying only one muscle, 100 patients with neuromuscular disorders (58 primary myopathies, 32 neurogenic disorders and 10 myotonic dystrophies) were submited to quantified electromyography (EMG) and muscle biopsy (MB) with fresh-frozen section plus histochemistry in the same muscle, but on the opposite side. The EMG was abnormal in 98% and MB in 93% of the cases. EMG and MB had a concordance of 84.3% in the neurogenic disorders and 84.77% in the primary myopathies. A correlation of 80% was obtained between all MB and EMG (including the cases of myotonic dystrophies), regarding the origin of the pathogenic process (p<0.01). The EMG had 5% inconsistences and the MB 11%, with respect to the pathogenic process. When the myotonic dystrophy was separated from the primary myopathies and from the denervation disorders, a complete concordance was found in all MB and had only 3.4% inconsistences in the denervation disorders and 3.1% in the primary myopathies.

RESUMO

A fim de verificar qual a correlação entre uma biópsia muscular e a eletromiografia quando um único músculo é estudado, bem como verificar a possibilidade de evitar eletromiografias extensivas e dolorosas em determinadas doenças, foram investigados 100 pacientes com doenças neuromusculares (58 com miopatias primárias, 32 doenças que determinam desinervação e 10 distrofias miotônicas). Todos os casos foram submetidos a eletromiografia quantificada (EMG) e a biópsia muscular (BM), utilizando técnicas de colorações a fresco e pela histoquímica, realizadas no mesmo músculo, mas em lados opostos do paciente. A EMG foi anormal em 98% e a BM in 93% dos casos. A EMG e a BM tiveram concordância de 84,3% nas doenças neurogênicas e 84,77% nas miopatias primárias. Foi obtida correlação de 80% entre a EMG e a BM em todos os casos, com relação à patogenia do processo (p<0,01). A EMG teve 5% de inconsistências e a BM 11%, em relação ao diagnóstico patogênico. Quando a distrofia miotônica foi separada das miopatias primárias e dos processos que determinam desinervação, uma concordância completa foi encontrada entre todas as BM e a EMG mostrou inconsistências somente em 3,4% das doenças que determinam desinervação e 3,1% das miopatias primárias, sugerindo que a distrofia miotônica deva ser classificada em um grupo separado (neuromiopatias). Os autores discutem os dados encontrados em relação à literatura existente e concluem que, dependendo da avaliação clínica, é possível submeter os pacientes a somente um dos procedimentos (geralmente a BM), utilizando ambos os procedimentos somente nos casos em que não foi possível chegar a um diagnóstico, sendo então examinados diversos músculos na EMG.

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Especialidade Neurologia, Departamento de Clínica Médica, Hospital de Clínicas da Universidade Federal do Paraná - Rua General Carneiro 191 - 80000 Curitiba PR - Brasil.

1. Astrom KE, Adams RA - Pathological reactions of the skeletal muscle fibre in man. In Walton J (ed): Disorders of the Voluntary Musicle. Churchill-Livingstone, Edinburg, 1981.
2. Batten FE, Gibb HP - Myotonic atrophic. Brain 32: 187, 1909.
3. Begin R, Bureau MA, Lupien L, Bernier J-P, Lemieus B - Pathogenesis of respiratory insuficiency in myotonic dystrophy: the mechanical factors. Am Rev Resp Dis 125: 312, 1982.
4. Black JT, Bhatt GP, De Jesus PV, Schotland DL, Rowland LP - Diagnostic accuracy of clinical data, quantitative electromyography and histochemistry in neuromuscular disease: a study of 105 cases. J Neurol Sci 21: 59, 1974.
5. Blanton PL, Leher RP, Martin JH, Biggs NL - Further observations on the histologic response of rat skeletal muscle to EMG fine wire-electrodes: significance of insulation. Electromyography 11: 475, 1971.
6. Blanton PL, Leher RP, Morelandü JE, Biggs NL - Observation on the histologic response, of rat skeletal muscle to EMG indwelling wire electrodes. Electromyography 11: 465, 1971.
7. Brooke MH, Kaiser KK - Muscle fiber types: how many and what kind. Arch Neurol 23: 369, 1970.
8. Brooke MH, Kaiser KK - The use and abuse of muscle histochemistry. Ann NY Acad Sci 228: 121, 1974.
9. Brusa A, Loeb C, Moretti G, Sacco G - A comparison of histologic and electromyographic findings in various neuromuscular disorders. Neurology 13: 630, 1963.
10. Buchthal F - An Introduction to Electromyography. Scandinavian Univ Books, Gyldeldal-Kobenhanrm, 1957.
11. Buchthal F - Te electromyogram: its value in the diagnosis of neuromuscular disorders. World Neurol 3: 16, 1962.
12. Buchthal F, Clemmesen S - On the differentiation of muscle atrophy by electromyography. Acta Psychiat Neurol 16: 143, 1941.
13. Buchthal F, Kamieniecka Z - The diagnostic yield of quantified electromyography and quantified muscle biopsy in neuromuscular disorders. Muscle & Nerve 5: 265, 1982.
14. Buchthal F, Rosenfalck P - Spontaneous electrical activity of human muscle. Electroenceph Clin Neurophysiol 20: 321, 1966.
15. Caruso G, Buchthal F - Refractory period of muscle and electromyographic findings in relatives of patients with muscular dystrophy. Brain 88: 29, 1965.
16. Chrissian SA, Stolov WC, Hondladarom T - Needle electromyography: its effect on serum creatine phosphokinase activity. Arch Phys Med Rehabil 57: 114, 1976.
17. Conceição DNF, Silva MLM - Níveis imunoglobulínicos no soro de pacientes com distrofia miotônica. Rev Bras Pesq Med Biol 7: 549, 1974.
18. Cullen MJ, Mastaglia FL - Pathological reaction of skeletal muscle. In Mastaglia FL, Walton J (eds): Skeletal Muscle Pathology, Churchill-Livingstone, Edinburg, 1982.
19. Daube JR - The description of motor unit potentials in electromyography. Neurology 28: 263, 1978.
20. Desmedt JE, Borenstein S - Relationship of spontaneous fibrillation potentials to muscle fibre segmentation in human muscular dystrophy. Nature 258: 531, 1975.
21. Dubowitz V, Brooke MG - Muscle Biopsy: a Modern Approach. Saunders, London, 1973.
22. Duchenne GB - Reeherches sur la paralysie musculaire pseudo-hypertrophique ou para-lysie myo-sclerosique (2e. article). Archives Genérales de Médicine 11 :179, 1868.
23. Duchenne GB - Recherches sur la paralysie musculaire pseudo-hypertrophique ou paralysie myo-sclerosique (3e. article). Archives Genérales de Medicine 11: 305, 1868.
24. Engel WK - Focal myopathic changes produced by electromyographic and hypodermic needles: needle myopathy. Arch Neurol 16: 509, 1967.
25. Engel WK - Brief, small, abundant motor-unit potentials: a further critique of electromyographic interpretation. Neurology 25: 173, 1975.
26. Engel WK - Investigative approach to muscular dystrophies. In Griggs RC, Moxley RT (eds): Advances in Neurology, vol. 17, Raven, New York, 1977.
27. Engel WK, Brooke MH - Histochemistry of myotonic disorders. In Kuhn E (ed): Symposion uber progressive Muskeldystrophie, Springer, Berlin, 1966.
28. Engel WK, Brooke MH - Muscle biopsy as a clinical diagnostic aid. In Fields WS (ed): Neurological Diagnostic Techniques. Charles C. Thomas, Springfield, 1968.
29. Erb W - Dystrophia muscularis progressiva: klinische und pathologische-anatomische Studien. Dtsch Z Nervenk 1: 173, 1891.
30. Esslen E, Ische F, Lambert EH, Lieberson WT, Simpson JA - Terminology of electromyography. Electroenceph Clin Neurophysiol 26: 224, 1969.
31. Galvão PAB, Werneck LC, Germiniani H, Cunha GP - O electrocardiograma nas distrofias musculares progressivas e doenças miotônicas: estudo de 77 pacientes. Arq Bras Cardiol 42: 273, 1984.
32. Goodgold J, Eberstein A - Electrodiagnosis of Neuromuscular Disease. Williams & Wilkins, Baltimore, 1972.
33. Griesinger W - Ueber Muskelhypertrophie. Archiv der Heilkund 6: 1, 1865.
34. Hausmanowa-Petrusewicz I, Emeryk B, Wasowicz B, Kopec E - Electromyography in neuro-muscular diagnostics. Electromyography 7: 203, 1967.
35. Hausmanowa-Petrusewicz I, Jedrzejowska G - Correlation between electromyographic findings and muscle biopsy in cases of neuromuscular disease. J Neurol Sci 13: 85, 1971.
36. Hayasaka S, Kiyosawa M, Katsumata S, Honda M, Takase S, Minuzo K - Ciliary and retinal changes in myotonic dystrophy. Arch Ophthalm 102: 88, 1984.
37. Humphrey J, Shy GN - Diagnostic electromyography. Arch Neurol 6: 339, 1962.
38. Kimura J - Electrodyagnosis in Diseases of Nerve and Muscle: Principles and Practice. FA Davis, Philadelphia, 1983.
39. Lenman JAR, Ritchie AR - Clinical Electromyography. Pitman, London, 1977.
40. Maze M, Novis BH, Lurie BB, Bank S - Involuntary muscle involvement in dystrophia myotonica: case report. South Afr Med J 47: 1947, 1973.
41. McComas AJ, Sica REP - Muscular dystrophy: myopathy or neuropathy. Lancet 1: 1119, 1970.
⁴²
Medical Research Council - Aids to the Examination of Peripheral Nervous System. Mem 45 (HMSO), London, 1976.
43. Micaglio GF, Negrini P, Fardini P - The diagnostic value of EMG compared with that of muscle biopsy in 71 myopathies. Acta Neurol (Napoli) 35: 51, 1980.
44. Moxley RT, Corbett AJ, Minaker KL, Rowe JW - Whole body Insulin resistance in myotonic dystrophy. Ann Neurol 15: 157, 1984.
45. Moxley RT, Griggs RC, Goldblati D - Muscle insulin resistance in myotonic dystrophy: effect of supraphysiologic insulinization. Neurology 30: 1077, 1980.
46. Okuno T, Mori K, Furomi K, Takeoka T, Kondo K - Myotonic dystrophy and hyperthyroidism. Neurology 31: 91, 1981.
47. Paakari I, Mumenthaler M - Needle myopathy: an experimental study. J Neurol 208: 133, 1974.
48. Panayiotopoulos CP, Scarpalezos S - Neural and muscular involvement in dystrophia myotonica. Lancert 2: 329, 1975.
49. Pollock M, Dyck PJ - Peripheral nerve morphometry in myotonic dystrophy. Arch Neurol 33: 33, 1976.
50. Roses AD, Appel SH - Muscular dystrophies. Lancet 2: 1400, 1974,
51. Roses AD, Butterfield A, Appel SH, Chestnut DB - Phenytoin and membrane fluiditi in myotonic dystrophy. Arch Neurol 32: 535, 1975.
52. Sandstedt PER - Effects of previous electromyographic examination studied by frequency analysis, muscle biopsy and creatine kinase. Acta Neurol Scand 64: 303, 1981.
53. Schwartz RA, Archibald KC, Hagstrom JW - Correlative findings by electromyography and muscle biopsy in neuromuscular disorders. Arch Phys Med Rehab 47: 653, 1966.
54. Seay AR, Zitter FA, Hill HR - Abnormal leucocyte electrophoretic mobility in myotonic dystrophy. J Neurol Sci 44: 13, 1979.
55. Steinert H - Uber das klinische und anatomische Bild der Muskelschwunds der Myotoniker. Dtsch Z Nervenk 37: 58, 1909.
56. Takahashi K, Kameyama M - Electromyography and histopathology of muscle and spinal cord: analysis of 105 skeletal muscle from 31 autopsy cases. J Neurol Sci 16: 465, 1972.
57. Uemura N, Tanaka H, Niimura T, Hashiguchi N, Yoshimura M, Terashi S, Kanehisa T - Electrophysiological and histological abnormalities of heart in myotonic dystrophy. Am Heart J 86: 616, 1973.
58. Werneck LC - O valor da biópsia muscular em neurologia: análise de 290 exames a fresco e pela histoquimica. Rev Bras Clin Terap 10 (supl): 2, 1971.
59. Zellweger H, Ionasescu V - Myotonic dystrophy and its differential diagnosis. Acta Neurol Scand 49 (supl): 1, 1973.

Muscle biopsy correlated with electromyography: study of 100 cases

Correlação entre biópsia muscular e eletromiografia: estudo de 100 casos

Publication Dates

Publication in this collection
22 June 2011
Date of issue
June 1988

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

[1] 1. Astrom KE, Adams RA - Pathological reactions of the skeletal muscle fibre in man. In Walton J (ed): Disorders of the Voluntary Musicle. Churchill-Livingstone, Edinburg, 1981.

[2] 2. Batten FE, Gibb HP - Myotonic atrophic. Brain 32: 187, 1909.

[3] 3. Begin R, Bureau MA, Lupien L, Bernier J-P, Lemieus B - Pathogenesis of respiratory insuficiency in myotonic dystrophy: the mechanical factors. Am Rev Resp Dis 125: 312, 1982.

[4] 4. Black JT, Bhatt GP, De Jesus PV, Schotland DL, Rowland LP - Diagnostic accuracy of clinical data, quantitative electromyography and histochemistry in neuromuscular disease: a study of 105 cases. J Neurol Sci 21: 59, 1974.

[5] 5. Blanton PL, Leher RP, Martin JH, Biggs NL - Further observations on the histologic response of rat skeletal muscle to EMG fine wire-electrodes: significance of insulation. Electromyography 11: 475, 1971.

[6] 6. Blanton PL, Leher RP, Morelandü JE, Biggs NL - Observation on the histologic response, of rat skeletal muscle to EMG indwelling wire electrodes. Electromyography 11: 465, 1971.

[7] 7. Brooke MH, Kaiser KK - Muscle fiber types: how many and what kind. Arch Neurol 23: 369, 1970.

[8] 8. Brooke MH, Kaiser KK - The use and abuse of muscle histochemistry. Ann NY Acad Sci 228: 121, 1974.

[9] 9. Brusa A, Loeb C, Moretti G, Sacco G - A comparison of histologic and electromyographic findings in various neuromuscular disorders. Neurology 13: 630, 1963.

[10] 10. Buchthal F - An Introduction to Electromyography. Scandinavian Univ Books, Gyldeldal-Kobenhanrm, 1957.

[11] 11. Buchthal F - Te electromyogram: its value in the diagnosis of neuromuscular disorders. World Neurol 3: 16, 1962.

[12] 12. Buchthal F, Clemmesen S - On the differentiation of muscle atrophy by electromyography. Acta Psychiat Neurol 16: 143, 1941.

[13] 13. Buchthal F, Kamieniecka Z - The diagnostic yield of quantified electromyography and quantified muscle biopsy in neuromuscular disorders. Muscle & Nerve 5: 265, 1982.

[14] 14. Buchthal F, Rosenfalck P - Spontaneous electrical activity of human muscle. Electroenceph Clin Neurophysiol 20: 321, 1966.

[15] 15. Caruso G, Buchthal F - Refractory period of muscle and electromyographic findings in relatives of patients with muscular dystrophy. Brain 88: 29, 1965.

[16] 16. Chrissian SA, Stolov WC, Hondladarom T - Needle electromyography: its effect on serum creatine phosphokinase activity. Arch Phys Med Rehabil 57: 114, 1976.

[17] 17. Conceição DNF, Silva MLM - Níveis imunoglobulínicos no soro de pacientes com distrofia miotônica. Rev Bras Pesq Med Biol 7: 549, 1974.

[18] 18. Cullen MJ, Mastaglia FL - Pathological reaction of skeletal muscle. In Mastaglia FL, Walton J (eds): Skeletal Muscle Pathology, Churchill-Livingstone, Edinburg, 1982.

[19] 19. Daube JR - The description of motor unit potentials in electromyography. Neurology 28: 263, 1978.

[20] 20. Desmedt JE, Borenstein S - Relationship of spontaneous fibrillation potentials to muscle fibre segmentation in human muscular dystrophy. Nature 258: 531, 1975.

[21] 21. Dubowitz V, Brooke MG - Muscle Biopsy: a Modern Approach. Saunders, London, 1973.

[22] 22. Duchenne GB - Reeherches sur la paralysie musculaire pseudo-hypertrophique ou para-lysie myo-sclerosique (2e. article). Archives Genérales de Médicine 11 :179, 1868.

[23] 23. Duchenne GB - Recherches sur la paralysie musculaire pseudo-hypertrophique ou paralysie myo-sclerosique (3e. article). Archives Genérales de Medicine 11: 305, 1868.

[24] 24. Engel WK - Focal myopathic changes produced by electromyographic and hypodermic needles: needle myopathy. Arch Neurol 16: 509, 1967.

[25] 25. Engel WK - Brief, small, abundant motor-unit potentials: a further critique of electromyographic interpretation. Neurology 25: 173, 1975.

[26] 26. Engel WK - Investigative approach to muscular dystrophies. In Griggs RC, Moxley RT (eds): Advances in Neurology, vol. 17, Raven, New York, 1977.

[27] 27. Engel WK, Brooke MH - Histochemistry of myotonic disorders. In Kuhn E (ed): Symposion uber progressive Muskeldystrophie, Springer, Berlin, 1966.

[28] 28. Engel WK, Brooke MH - Muscle biopsy as a clinical diagnostic aid. In Fields WS (ed): Neurological Diagnostic Techniques. Charles C. Thomas, Springfield, 1968.

[29] 29. Erb W - Dystrophia muscularis progressiva: klinische und pathologische-anatomische Studien. Dtsch Z Nervenk 1: 173, 1891.

[30] 30. Esslen E, Ische F, Lambert EH, Lieberson WT, Simpson JA - Terminology of electromyography. Electroenceph Clin Neurophysiol 26: 224, 1969.

[31] 31. Galvão PAB, Werneck LC, Germiniani H, Cunha GP - O electrocardiograma nas distrofias musculares progressivas e doenças miotônicas: estudo de 77 pacientes. Arq Bras Cardiol 42: 273, 1984.

[32] 32. Goodgold J, Eberstein A - Electrodiagnosis of Neuromuscular Disease. Williams & Wilkins, Baltimore, 1972.

[33] 33. Griesinger W - Ueber Muskelhypertrophie. Archiv der Heilkund 6: 1, 1865.

[34] 34. Hausmanowa-Petrusewicz I, Emeryk B, Wasowicz B, Kopec E - Electromyography in neuro-muscular diagnostics. Electromyography 7: 203, 1967.

[35] 35. Hausmanowa-Petrusewicz I, Jedrzejowska G - Correlation between electromyographic findings and muscle biopsy in cases of neuromuscular disease. J Neurol Sci 13: 85, 1971.

[36] 36. Hayasaka S, Kiyosawa M, Katsumata S, Honda M, Takase S, Minuzo K - Ciliary and retinal changes in myotonic dystrophy. Arch Ophthalm 102: 88, 1984.

[37] 37. Humphrey J, Shy GN - Diagnostic electromyography. Arch Neurol 6: 339, 1962.

[38] 38. Kimura J - Electrodyagnosis in Diseases of Nerve and Muscle: Principles and Practice. FA Davis, Philadelphia, 1983.

[39] 39. Lenman JAR, Ritchie AR - Clinical Electromyography. Pitman, London, 1977.

[40] 40. Maze M, Novis BH, Lurie BB, Bank S - Involuntary muscle involvement in dystrophia myotonica: case report. South Afr Med J 47: 1947, 1973.

[41] 41. McComas AJ, Sica REP - Muscular dystrophy: myopathy or neuropathy. Lancet 1: 1119, 1970.

[42] ⁴²
Medical Research Council - Aids to the Examination of Peripheral Nervous System. Mem 45 (HMSO), London, 1976.

[43] 43. Micaglio GF, Negrini P, Fardini P - The diagnostic value of EMG compared with that of muscle biopsy in 71 myopathies. Acta Neurol (Napoli) 35: 51, 1980.

[44] 44. Moxley RT, Corbett AJ, Minaker KL, Rowe JW - Whole body Insulin resistance in myotonic dystrophy. Ann Neurol 15: 157, 1984.

[45] 45. Moxley RT, Griggs RC, Goldblati D - Muscle insulin resistance in myotonic dystrophy: effect of supraphysiologic insulinization. Neurology 30: 1077, 1980.

[46] 46. Okuno T, Mori K, Furomi K, Takeoka T, Kondo K - Myotonic dystrophy and hyperthyroidism. Neurology 31: 91, 1981.

[47] 47. Paakari I, Mumenthaler M - Needle myopathy: an experimental study. J Neurol 208: 133, 1974.

[48] 48. Panayiotopoulos CP, Scarpalezos S - Neural and muscular involvement in dystrophia myotonica. Lancert 2: 329, 1975.

[49] 49. Pollock M, Dyck PJ - Peripheral nerve morphometry in myotonic dystrophy. Arch Neurol 33: 33, 1976.

[50] 50. Roses AD, Appel SH - Muscular dystrophies. Lancet 2: 1400, 1974,

[51] 51. Roses AD, Butterfield A, Appel SH, Chestnut DB - Phenytoin and membrane fluiditi in myotonic dystrophy. Arch Neurol 32: 535, 1975.

[52] 52. Sandstedt PER - Effects of previous electromyographic examination studied by frequency analysis, muscle biopsy and creatine kinase. Acta Neurol Scand 64: 303, 1981.

[53] 53. Schwartz RA, Archibald KC, Hagstrom JW - Correlative findings by electromyography and muscle biopsy in neuromuscular disorders. Arch Phys Med Rehab 47: 653, 1966.

[54] 54. Seay AR, Zitter FA, Hill HR - Abnormal leucocyte electrophoretic mobility in myotonic dystrophy. J Neurol Sci 44: 13, 1979.

[55] 55. Steinert H - Uber das klinische und anatomische Bild der Muskelschwunds der Myotoniker. Dtsch Z Nervenk 37: 58, 1909.

[56] 56. Takahashi K, Kameyama M - Electromyography and histopathology of muscle and spinal cord: analysis of 105 skeletal muscle from 31 autopsy cases. J Neurol Sci 16: 465, 1972.

[57] 57. Uemura N, Tanaka H, Niimura T, Hashiguchi N, Yoshimura M, Terashi S, Kanehisa T - Electrophysiological and histological abnormalities of heart in myotonic dystrophy. Am Heart J 86: 616, 1973.

[58] 58. Werneck LC - O valor da biópsia muscular em neurologia: análise de 290 exames a fresco e pela histoquimica. Rev Bras Clin Terap 10 (supl): 2, 1971.

[59] 59. Zellweger H, Ionasescu V - Myotonic dystrophy and its differential diagnosis. Acta Neurol Scand 49 (supl): 1, 1973.