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Discriminating neurogenic from myopathic disease via measurement of muscle anisotropy
Author(s) -
Garmirian Lindsay P.,
Chin Anne B.,
Rutkove Seward B.
Publication year - 2009
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.21115
Subject(s) - amyotrophic lateral sclerosis , anisotropy , biceps , medicine , electrical impedance myography , neuromuscular disease , tibialis anterior muscle , anatomy , skeletal muscle , pathology , disease , physics , quantum mechanics , vasodilation
Skeletal muscle is electrically anisotropic, with a tendency for applied electrical current to flow more readily along muscle fibers than across them. In this study, we assessed a method for non‐invasive measurement of anisotropy to determine its potential to serve as a new technique for distinguishing neurogenic from myopathic disease. Measurements were made on the biceps brachii and tibialis anterior muscles in 15 normal subjects and 12 patients with neuromuscular disease (6 with amyotrophic lateral sclerosis and 6 with various myopathies) using 50 kH Z applied current. Consistent multi‐angle anisotropic patterns were found for reactance and phase in both muscles in normal subjects. Normalized anisotropy differences for each subject were defined, and group average values identified. The amyotrophic lateral sclerosis (ALS) patients demonstrated increased and distorted anisotropy patterns, whereas myopathic patients demonstrated normal or reduced anisotropy. These results suggest that non‐invasive measurement of muscle anisotropy has potential for diagnosis of neuromuscular diseases. © 2008 Wiley Periodicals, Inc. Muscle Nerve, 2009