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Selectivity of conventional electrodes for recording motor evoked potentials: An investigation with high‐density surface electromyography
Author(s) -
Gallina Alessio,
Peters Sue,
Neva Jason L.,
Boyd Lara A.,
Garland S. Jayne
Publication year - 2017
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.25412
Subject(s) - electromyography , transcranial magnetic stimulation , physical medicine and rehabilitation , stimulation , medicine , evoked potential , electrophysiology , psychology , neuroscience , audiology
The objective of this study was to determine whether motor evoked potentials (MEPs) elicited with transcranial magnetic stimulation and measured with conventional bipolar electromyography (EMG) are influenced by crosstalk from non‐target muscles. Methods MEPs were recorded in healthy participants using conventional EMG electrodes placed over the extensor carpi radialis muscle (ECR) and high‐density surface EMG (HDsEMG). Fifty MEPs at 120% resting and active motor threshold were recorded. To determine the contribution of ECR to the MEPs, the amplitude distribution across HDsEMG channels was correlated with EMG activity recorded during a wrist extension task. Results Whereas the conventional EMG identified MEPs from ECR in >90% of the stimulations, HDsEMG revealed that spatial amplitude distribution representative of ECR activation was observed less frequently at rest than while holding a contraction ( P < 0.001). Conclusions MEPs recorded with conventional EMG may contain crosstalk from non‐target muscles, especially when the stimulation is applied at rest. Muscle Nerve 55 : 828–834, 2017