EMG of Electrically Stimulated Muscles

Does the amplitude of biceps brachii M waves increase similarly in both limbs during staircase, electrically elicited contractions?

“…(i) the stimulation electrodes were positioned in the most proximal portion of biceps brachii, where the nerve trunk and primary motor branches that supply this muscle are localized (Pacha Vicente et al 2005, Lee et al 2010, Cambon-Binder and Leclercq 2015); (ii) a bipolar stimulation technique was used with stimulation electrodes positioned in the transverse direction of the muscle, maximizing their distance over the biceps. Compared with the monopolar technique, in bipolar stimulation the current crosses muscle tissue with similar density (Botter and Merletti 2016) thus reducing the effects of geometrical factors (e.g. relative electrode-axon position) on motor unit recruitment; (iii) the analysis of differential EMG signals recorded with a relatively small inter-electrode distance probably attenuated a possible contribution of potentials coming from brachialis motor units that may have been activated during the stimulation protocol (Roeleveld et al 1997, Rodriguez-Falces et al 2013b.…”

“…As the M wave represents the summation of the motor unit action potentials synchronously evoked by an external electric stimulus (Botter and Merletti 2016), changes in the M-wave amplitude are usually assumed to reflect changes in the number of motor units activated (McComas et al 1971). Therefore, variations in the magnitude of the increments in the M-wave amplitude analysed in this study reflect variations in the relative number of additional motor units elicited in the muscle for increases in current intensity.…”

“…In this study we use incremental electrical stimulation (Botter et al 2009, Botter andMerletti 2016) to indirectly assess differences in motor unit recruitment between limbs. The massed action potentials (M wave) generated by an external electric stimulus and recorded using surface electrodes represents the summation of the synchronously evoked motor unit action potentials (Botter and Merletti 2016). Based on that, changes in the M-wave amplitude are usually assumed to reflect a change in the number of motor units activated (McComas et al 1971).…”

EMG Signs of Motor Units’ Enlargement in Stroke Survivors

“…To ensure there was an effect of stroke on the biceps brachii muscles evaluated in this study, we decided to disregard patients scoring greater than 90% in the Fugl-Meyer maximum score (i.e., patients with very mild or no motor impairment). In addition, methodological issues were considered to guarantee representative and selective EMGs of most biceps brachii motor units: (i) stimulation electrodes were positioned to ensure a similar charge density [31] impinged upon the nerve trunk and the nerve primary motor branches [32,33]; (ii) differential EMGs were sampled with a relatively small inter-electrode distance, attenuating any contribution from e.g., brachialis [34,35]; (iii) the linear interpolation in the stimulus-response curve allowed to compensate for the inability to increase the stimulation intensity by the same, relative amount between limbs. This is a conservative procedure given that across participants we observed a consistently smaller current range for the paretic limb before the interpolation.…”

Estudo Numérico De Um Equipamento De Secagem

“…Para fenômeno de indução de potencial transmembrana geralmente aplica-se campos pulsados com onda quadrada mono/bipolar e exponencial truncada mono/bipolar (BOTTER;MERLETTI, 2016;MARTY et al, 2006;VIANA et al, 2016).…”