Da amplitude à variabilidade: uma abordagem integrada sobre os efeitos da colocação de eletrodos no registro do potencial motor evocado

Abstract

Objective: To investigate the influence of three different electrode montages on the variability of Motor Evoked Potentials (MEPs) elicited by Transcranial Magnetic Stimulation (TMS) and recorded using surface Electromyography (sEMG). Methods: The study was conducted in sequential stages, including a literature review, pilot studies, and a main experiment. In the main experiment, the right Biceps Brachii muscle of eight (8) adult participants was assessed using sEMG to record MEPs obtained from three different electrode montages: (1) bipolar montage with electrodes positioned over the muscle belly; (2) bipolar montage recommended for MEP recording in clinical protocols; and (3) pseudomonopolar montage (belly–tendon). The montages differed in electrode location and interelectrode distance, resulting in different detection volumes. MEPs were recorded simultaneously across the three configurations. Results: The bipolar montage (2) demonstrated lower variability compared to the other two configurations evaluated. Conclusion: Montage (2) provides MEPs with lower coefficients of variation and higher amplitudes. Significance: Electrode configuration directly influences MEP amplitude and variability and should be carefully considered in TMS assessments to ensure greater reliability of measurements.