Alessio Gallina1, Sue Peters1, Jason L Neva2, Lara A Boyd2, S Jayne Garland2. 1. Graduate Program in Rehabilitation Sciences, University of British Columbia, Vancouver, British Columbia, Canada. 2. Department of Physical Therapy, University of British Columbia, 212 Friedman Building, 2177 Wesbrook Mall, Vancouver, British Columbia, V6T 1Z3, Canada.
Abstract
INTRODUCTION: 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.
INTRODUCTION: 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.
Authors: Hugo Massé-Alarie; Michael J G Bergin; Cyril Schneider; Siobhan Schabrun; Paul W Hodges Journal: Hum Brain Mapp Date: 2017-09-17 Impact factor: 5.038