Evaluation of Respiratory Muscle Activity by Means of Concentric Ring Electrodes

Abstract

Surface electromyography (sEMG) can be used for the evaluation of respiratory muscle activity. Recording sEMG involves the use of surface electrodes in a bipolar configuration. However, electrocardiographic (ECG) interference and electrode orientation represent considerable drawbacks to bipolar acquisition. As an alternative, concentric ring electrodes (CREs) can be used for sEMG acquisition and offer great potential for the evaluation of respiratory muscle activity due to their enhanced spatial resolution and simple placement protocol, which does not depend on muscle fiber orientation. The aim of this work was to analyze the performance of CREs during respiratory sEMG acquisitions. Respiratory muscle sEMG was applied to the diaphragm and sternocleidomastoid muscles using a bipolar and a CRE configuration. Thirty-two subjects underwent four inspiratory load spontaneous breathing tests which was repeated after interchanging the electrode positions. We calculated parameters such as (1) spectral power and (2) median frequency during inspiration, and power ratios of inspiratory sEMG without ECG in relation to (3) basal sEMG without ECG (Rins/noise), (4) basal sEMG

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.…”

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].…”

Assessment of the Non-linear Response of the fSampEn on Simulated EMG Signals

“…Respiratory EMG signal can be recorded in different locations of the trunk such as the costal diaphragm [2], [3] in the parasternal zone [4] or also in accessory muscles This work was supported in part by the CERCA Program/Generalitat de Catalunya, in part by the Secretaria d'Universitats i Recerca de la Generalitat de Catalunya under Grant GRC 2017 SGR 01770, in part by the Spanish Ministry of Science, Innovation and Universities under Grant RTI2018-098472-B-I00 MCIU/AEI/FEDER, UE. L. Estrada-Petrocelli, M. Lozano-García, A. Torres, and R. Jané are with the Institut de Bioenginyeria de Catalunya (IBEC), the Barcelona Institute of Science and Technology (BIST), Universitat Politècnica de Catalunya (UPC)•BarcelonaTech, of neck [5]. Its evaluation has been of clinical utility in the study of respiratory muscle activity in healthy subjects [2]- [5] and in patients with respiratory conditions [6], [7].…”