Current status of multichannel electrogastrography and examples of its use

Abstract

Electrogastrography (EGG) is a non-invasive diagnostic motility for recording gastric myoelectrical activity. Gastric myoelectrical activity was first recorded in 1922. Advances in recording equipment enabled widespread use of cutaneous EGG after 1985. Later, introduction of multichannel EGG (M-EGG) enabled measurement of electrical activity transmission. At present, M-EGG findings are used as objective indicators of gastric motility disorders caused by various diseases. EGG measures two categories of gastric electrical activity: electrical response activity, or spike potentials; and electrical control activity, or slow waves. The appearance of abnormal rhythmic electrical activity is indicative of abnormalities in gastric motility. The normal frequency range of gastric electrical activity (normogastria) is around 3 cycles per min. Multiple EGG parameters assist in the assessment of gastric myoelectrical activity, and significant correlations between EGG and other gastric motility tests have been demonstrated in many studies. In Japan, however, EGG remains in the exploratory stage, and its clinical use is limited. There are large variations in procedures and systems used in previous studies, thus there is a need for standardization of EGG procedures and technical terminology. Here, we outline the current status of EGG and report the M-EGG procedures used in our department in addition to our M-EGG findings.The abstract of this manuscript was presented during an educational seminar titled "Current status of gastrointestinal motility tests and keys for immediate implementation" at the 54th Annual Meeting of the Japan Society of Smooth Muscle Research

Lessons Learned: Gastric Motility Assessment During Driving Simulation

“…Non-invasive recording of myoelectrical potentials from stomach smooth muscles (EGG) was first described in the literature by Alvarez in 1921 [9]. Since then, the major progress in that area has been made during the past three decades, but the application of EGG in clinical practice is still limited [10,11]. The main component of EGG signals consists of a slow-wave, i.e.…”

A Combined Methodology to Eliminate Artifacts in Multichannel Electrogastrogram Based on Independent Component Analysis and Ensemble Empirical Mode Decomposition

“…The proposed work differs from the conventional methodology 1–7 of extracting gastric signals. Conventional acquisition of EGG 4,12–14 uses a lower sampling rate of (e.g 3–4 Hz) which partly avoids cardiac artifacts to be measured along with gastric signals. In contrary, this work advocates acquiring EGG at a higher sampling rate of 1000 Hz, there by allowing all the features of the cardiac cycle.…”

“…Still, acquiring gastric signals and identifying them in the presence of artifacts is not straightforward, like in cardiac signals, where the features are evident most of the time. The proposed work differs from the conventional methodology [1][2][3][4][5][6][7] of extracting gastric signals. Conventional acquisition of EGG 4,12-14 uses a lower sampling rate of (e.g 3-4 Hz) which partly avoids cardiac artifacts to be measured along with gastric signals.…”

“…The passband used in this work, that is, 0.015-0.15 Hz, is the most employed frequency range. [1][2][3][4]18 It can be easily noticed that artifacts occurring below 0.02 Hz (associated with drifts or body movements 29 ), which fall within this passband of the BPF, could be attenuated by the EEMD method, as seen in Figure 4 and Table 1. Both the EMD and EEMD methods use selective attenuation of artifacts with prior knowledge (by looking at their IFs in IMFs) of each artifact.…”

“…2,3 Meanwhile, apart from measuring EGG signals using a limited number of electrodes, multichannel measurements are thought to be suitable to understand the physiology of gastric slow waves in a better way. 4,5…”