Concentric ring electrodes for non-invasive recording of gastric myoelectric activity

Vectorgastrogram: dynamic trajectory and recurrence quantification analysis to assess slow wave vector movement in healthy subjects

“…Previous studies have proposed using the dominant frequency in the multichannel EGG recording cross-spectrum (DFCS) for robust assessment of high spatial stability components [ 46 , 60 ] or applying empirical mode decomposition to detect intrinsic mode functions [ 20 , 61 ]. Other works use a second order blind identification (SOBI) technique for this purpose, especially in magnetogastrographic [ 62 ] and manetoenterographic recordings [ 63 ].…”

“…To assess both the raw signals and mode signal extracted from the MVMD and their effectiveness in detecting the gastric SW and also to characterise the gastric SW in the fasting and fed states, we computed the following fasting and fed indicators per channel: Detection rate, DFCS (%): the ratio between the number of 5-min windows with a dominant SWF within the range of GSWF ± 0.3 cpm and the total number of windows analysed and channels [ 46 ]. Frequency instability coefficient, FIC (%): the ratio between the standard deviation and the average value of the SWF, which represents gastric SW variability throughout the recording [ 46 , 52 , 53 ]. Lower values indicate higher stability of frequency components over time.…”

“…Detection rate, DFCS (%): the ratio between the number of 5-min windows with a dominant SWF within the range of GSWF ± 0.3 cpm and the total number of windows analysed and channels [ 46 ].…”

“…Frequency instability coefficient, FIC (%): the ratio between the standard deviation and the average value of the SWF, which represents gastric SW variability throughout the recording [ 46 , 52 , 53 ]. Lower values indicate higher stability of frequency components over time.…”

Looking for optimal concentric ring electrodes: influence of design aspects on their performance

“…Therefore, one of the main benefits of CREs over disc electrodes is the enhanced spatial resolution, which has led to a better contrast to study the cardiac P-wave and its subcomponents than the traditional 12-lead electrocardiogram [3], more accurate identification of atrial fibrillation [4] and of cardiac depolarization waves on the body surface [5], better localization of activity in electroencephalogram movement-related potentials [1] and visual evoked potentials [6], and high-frequency activity in epileptic patients [7]. This enhanced spatial resolution also helps in reducing crosstalk and interference, facilitating the analysis and characterization of the target signal in a wide range of applications such as respiratory [8], uterine [9], intestinal [10], gastric [11], forearm [12,13], masticatory [14] and swallowing muscle [15] myoelectrical recordings. Furthermore, due to their spatial filtering function [16], CREs have been shown to reduce the low-pass filtering effect on body surface recordings, providing signals with a greater bandwidth than conventional disc electrodes and closer to that of the intramuscular recordings obtained with needle electrodes [15,17].…”