Fundamental Concepts of Bipolar and High-Density Surface EMG Understanding and Teaching for Clinical, Occupational, and Sport Applications: Origin, Detection, and Main Errors

Abstract

Surface electromyography (sEMG) has been the subject of thousands of scientific articles, but many barriers limit its clinical applications. Previous work has indicated that the lack of time, competence, training, and teaching is the main barrier to the clinical application of sEMG. This work follows up and presents a number of analogies, metaphors, and simulations using physical and mathematical models that provide tools for teaching sEMG detection by means of electrode pairs (1D signals) and electrode grids (2D and 3D signals). The basic mechanisms of sEMG generation are summarized and the features of the sensing system (electrode location, size, interelectrode distance, crosstalk, etc.) are illustrated (mostly by animations) with examples that teachers can use. The most common, as well as some potential, applications are illustrated in the areas of signal presentation, gait analysis, the optimal injection of botulinum toxin, neurorehabilitation, ergonomics, obstetrics, occupational medicine, and sport sciences. The work is primarily focused on correct sEMG detection and on crosstalk. Issues related to the clinical transfer of innovations are also discussed, as well as the need for training new clinical and/or technical operators in the field of sEMG.

Customizable, reconfigurable, and anatomically coordinated large-area, high-density electromyography from drawn-on-skin electrode arrays

“…The localization of all IZs from each row of the grid reveals an IZ band, representing the collective sites of motor unit innervation. From these high-density mapping results obtained with the DoS MEA, the average muscle fiber propagation velocity was calculated to be 6.33 m/s (similar to the values reported in literature ( 3 , 40 )), and individual motor units were detected by the DoS MEA as described in the Supplementary Material Appendix, Supplementary Materials and Methods and Supplementary Material Appendix , Fig. S13 .…”

“…Previous reports of high-density EMG of the trapezius muscle show only partial coverage that misses information from either the upper, middle, or lower regions ( 38 , 39 ). The electrodes and interconnects of DoS MEAs are tuned to the subject's specific muscle shape, and the interelectrode distance is determined based on the muscle geometry and intended application ( 40 ). By tuning the electrode size, density, overall arrangement, and interconnect design at the point of care, the DoS MEAs were fabricated in minutes to demonstrate their adaptability to smaller muscles like the flexors and extensors of the forearm, biceps, and triceps (Fig.…”

Automatic Identification of Involuntary Muscle Activity in Subacute Patients with Upper Motor Neuron Lesion at Rest—A Validation Study

“…Two assessors (authors AM and IC) visually inspected all epochs. Both have over two decades of experience with surface EMG and its use in neurorehabilitation including many publications surrounding the topic [ 18 , 19 , 20 , 21 , 22 , 23 , 24 ].…”

Nonlinear spatio-temporal filter to reduce crosstalk in bipolar electromyogram

“…Surface EMG is the signal recorded by electrodes placed on the skin and reflecting the bioelectric command inducing the contraction of a muscle [1]. The electrodes have a large detection volume [2,3], so that they can record also the contribution from other muscles than the target one of interest [4,5]. This undesired contribution, called crosstalk [6], is still an open problem in surface EMG.…”