Evaluation of Swallowing Related Muscle Activity by Means of Concentric Ring Electrodes

Abstract

Surface electromyography (sEMG) can be helpful for evaluating swallowing related muscle activity. Conventional recordings with disc electrodes suffer from significant crosstalk from adjacent muscles and electrode-to-muscle fiber orientation problems, while concentric ring electrodes (CREs) offer enhanced spatial selectivity and axial isotropy. The aim of this work was to evaluate CRE performance in sEMG recordings of the swallowing muscles. Bipolar recordings were taken from 21 healthy young volunteers when swallowing saliva, water and yogurt, first with a conventional disc and then with a CRE. The signals were characterized by the root-mean-square amplitude, signal-to-noise ratio, myopulse, zero-crossings, median frequency, bandwidth and bilateral muscle cross-correlations. The results showed that CREs have advantages in the sEMG analysis of swallowing muscles, including enhanced spatial selectivity and the associated reduction in crosstalk, the ability to pick up a wider range of EMG frequency components and easier electrode placement thanks to its radial symmetry. However, technical changes are recommended in the future to ensure that the lower CRE signal amplitude does not significantly affect its quality. CREs show great potential for improving the clinical monitoring and evaluation of swallowing muscle activity. Future work on pathological subjects will assess the possible advantages of CREs in dysphagia monitoring and diagnosis.

Comprehensive Optimization of the Tripolar Concentric Ring Electrode Based on Its Finite Dimensions Model and Confirmed by Finite Element Method Modeling

“…Therefore, despite this small decrease in the Laplacian amplitude obtained for the larger electrode sizes in the FEM results ( Figure 4 , panel A), the amplitude of the raw potential signals to be recorded under experimental conditions can be expected to increase with an increase in the electrode size. In fact, in various applications [ 11 , 12 ], it has been seen that the lower amplitude of the signals captured with CREs compared with the signals recorded via conventional disc electrodes can lead to signals of a poorer quality (lower signal-to-noise ratio), therefore suggesting the need to use larger CREs while having to sacrifice the spatial resolution. In this sense, the optimal TCRE configuration has been shown to provide the highest Laplacian amplitude values for a given electrode size ( Figure 4 , panel A), thus offering a quantitative advantage over other TCRE configurations such as CIRD or LIIRD.…”

“…Not only did the obtained results show that the normalized amplitude of the P-wave of signals recorded via CRE at CMV1 was significantly greater than any of the standard 12-lead recordings, offering a better contrast for the study of the P-wave, important in practical diagnostic applications, but that the relationship between different CRE configurations in terms of their normalized amplitude of the P-wave and signal-to-noise ratio was consistent with the analytical results for the Laplacian estimation error from [ 16 ] (for two tripolar configurations assessed) and [ 15 ] (for bipolar versus tripolar versus quadripolar configurations). Other examples of recent biomedical applications of CREs that could potentially benefit from the insights stemming from this study include, but are not limited to, electroencephalogram- (source localization of high-frequency activity [ 6 ] and seizure detection [ 9 ] in epilepsy patients), electroenterogram- (identification of the intestinal slow waves [ 3 ]), and electromyogram-based (evaluation of swallowing [ 11 ] and respiratory [ 12 ] muscle activity) applications.…”

“…This ability entails enhanced spatial resolution and a better capability to differentiate the activity of dipole sources in different areas [ 1 ]. The properties shared by the majority of currently used CREs are as follows: relatively small radius of the central disc (compared with the radius of the electrode) and/or equal and small widths of concentric rings (compared with the radius of the electrode) [ 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. These properties stem, at least partially, from the use of the negligible dimensions model (NDM) of a CRE—a Cartesian grid where the central disc is represented by a single point (of negligible diameter) in the middle of the grid and the rings are represented by concentric circles (of negligible width) around it.…”

Directed Functional Coordination Analysis of Swallowing Muscles in Healthy and Dysphagic Subjects by Surface Electromyography

“…sEMG is the extracellular recording of the electrical activity of muscle fibres on the skin surface, which reflects the electrophysiological muscle response to nerve stimulation. Most swallowingrelated studies have used sparse sEMG electrodes to sense the activity and have extracted electrophysiological information from face and neck muscles, e.g., from the masseteric, submental (suprahyoid), and infrahyoid regions [14][15][16][17][18][19][20]. Unlike classical temporal and spectral parameters from a single sEMG channel, sEMG signal characterization cannot precisely characterize the complete swallowing process.…”

Solving the Inter-Ring Distances Optimization Problem for Pentapolar and Sextopolar Concentric Ring Electrodes Based on the Negligible Dimensions Model of the Electrode

“…Concentric ring electrodes (CREs; tripolar configuration shown in Figure 1A) are noninvasive and wearable sensors for electrophysiological measurement capable of estimating the surface Laplacian (second spatial derivative of surface potential) at each electrode, which is not feasible with conventional disc electrodes (Figure 1B), and constitutes CRE's practical relevance to the wearable sensor field [1][2][3][4][5][6][7][8][9][10]. Recent examples of biomedical applications utilizing CREs involve electroencephalograms (source localization of highfrequency activity [5] and seizure detection [8] in epilepsy patients), electroenterograms (identification of the intestinal slow waves [2]), and electromyograms (evaluation of swallowing [11] and respiratory [10] muscle activity). Previously, progress was made toward optimization of inter-ring distances (distances between the recording surfaces of a CRE), maximizing the accuracy of the surface Laplacian estimate based on the negligible dimensions model (NDM) of the electrode [12].…”