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Prior muscle activation affects the compound muscle action potential
Author(s) -
Peterson Gordon W.,
Tsao Bryan E.,
Nist Laura D.,
Estevez Dennys,
Brandstater Murray E.
Publication year - 2019
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.26463
Subject(s) - compound muscle action potential , medicine , electromyography , electrophysiology , anesthesia , anatomy , cardiology , physical medicine and rehabilitation
This study was performed to evaluate the effect of prior voluntary activation of a muscle on the subsequently‐recorded compound muscle action potential (CMAP). Methods The CMAPs from the hypothenar, thenar, and extensor digitorum brevis muscles were recorded in 6 healthy volunteers at rest and for up to 30 min following 5 separate epochs of up to 20 s of voluntary muscle activation. Results There was consistent, significant ( P < 0.02) enhancement of the negative area, amplitude, and duration of the CMAP after activation. The enhancement was maximal, up to 144% of baseline, within about 1 min post‐activation; thereafter, the CMAP gradually returned to baseline over about 15 min. Discussion Activation of a muscle within several minutes prior to testing enhances the subsequently‐recorded CMAP. This observation highlights prior muscle activation as a physiological variable that influences the size of the CMAP during motor nerve conduction studies. Muscle Nerve , 2019