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Discharge rates in electromyography distinguish early between peripheral and central paresis
Author(s) -
Jürgens Tim P.,
Puchner Christoph,
SchulteMattler Wilhelm J.
Publication year - 2012
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.23453
Subject(s) - paresis , electromyography , lesion , peripheral , medicine , motor unit , weakness , surgery , anatomy , physical medicine and rehabilitation
Abnormally increased discharge rates (DRs) of motor unit potentials on concentric needle electromyography (CNEMG) indicate a loss of motor units in peripheral neurogenic lesions. Methods: To determine when increased DRs occur during the course of a peripheral nerve lesion, we retrospectively analyzed CNEMG recordings of 19 patients with acute weakness of peripheral origin. Results: The initial CNEMG studies took place from 3.7 hours to 10 days after the onset of the lesion. Abnormally increased DRs (≥20/s) were found in all but 1 of the muscles in which MRC grade was <4. Peripheral neurogenic damage was confirmed in all patients thereafter. The DRs depended on neither the kind of lesion nor the time between onset and CNEMG examination. Conclusions: The measurement of DRs of motor unit potentials is helpful immediately after a sudden paresis of MRC grade 3 or worse to differentiate between a central and a peripheral lesion. Muscle Nerve 46: 596–598, 2012