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Single‐fiber electromyography in neuromuscular disorders: Correlation of muscle histochemistry, single‐fiber electromyography, and clinical findings
Author(s) -
Bertorini Tulio E.,
Stalberg Erik,
Yuson Carlo P.,
Engel W. King
Publication year - 1994
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880170314
Subject(s) - reinnervation , denervation , electromyography , medicine , myotonic dystrophy , muscle biopsy , myopathy , neuromuscular disease , myotonia , anatomy , biopsy , disease , physical medicine and rehabilitation
We performed single‐fiber electromyography (SFEMG) and correlated the results with muscle‐biopsy histochemistry in 56 patients with various neuromuscular diseases. Increased muscle‐fiber density, delineated by SFEMG, was most prominent in diseases of ordinary denervation, namely motor neuron disorders and peripheral neuropathies, and it correlated with histochemical fiber type grouping. Both phenomena reflect denervation followed by reinnervation. In patients with central core disease and rod disease, fiber density was not increased despite massive type I fiber predominance. The normal distribution of type I fiber subtypes in those patients indicated that their fiber predominance was not due to sprouting and reinnervation, but probably to paucity of the type II fibers. In type I fiber hypotrophy with central nuclei, fiber density was increased, perhaps attributable to the small diameter and consequent denser packing of the type I fibers. Fiber density was slightly increased in the majority of patients with acidmaltase deficiency, limb‐girdle dystrophy, and polymyositis, in nearly half with mitochondrial myopathy, and in 1 older Duchenne dystrophy patient. In these myopathic disorders, myogenous deinnervation (followed by reinnervation) is one possible explanation. Normal fiber density was present in all patients with muscle phosphorylase deficiency, myotonia congenita, and in the hypokalemic periodic paralysis patients under age 40. © 1994 John Wiley & Sons, Inc.