Purpose of
this Cyberzine Disclaimer and Copyright Introductory Pictures
Electrogastrography
Gastric Electrical
Activity (GEA)
Selected Topics on Electrogastrography
The Cyberzine on
Electrogastrography was created to provide a free scientific forum for the
researchers in the fields of electrogastrography(EGG) and gastric
electrical activity (GEA).
The objective of the EGG cyberzine
is to present a comprehensive overview of electrogastrography
from methodological point of view, explain the quantitative information that
can be extracted from EGG, and discuss clinical studies related to gastric
electrical activity.
The cyberzine is maintained by:
Clinical and methodological aspects
of electrogastrography that are discussed in this Cyberzine are supervised by
Dr. Kenneth L. Bowes, Professor of Surgery at the University of Alberta,
technical and methodological aspects are supervised by Dr. Martin P. Mintchev, Professor
of Electrical and Computer Engineering, University of Calgary, and Adjunct
Professor of Surgery (University of Alberta).
Researchers are encouraged to
submit to the above address materials related to electrogastrography which they
consider important. The documents should be saved as files on a 3.5"
diskette using MS Word for Windows (version 6.0 or lower). Please provide your
figures in .GIF format. Note that tables and formulae might not appear as
desired. Try to avoid figures and formulae as much as you can. All submissions
will be reviewed and either completely accepted or completely rejected. In
general, all contributions will be accepted but unethical, repetitive or
offensive submissions will be excluded. The submitted diskettes are
non-refundable. You will be able to check whether your contribution is accepted
by browsing this EGG Cyberzine.
This Cyberzine was not designed to
be a medical advisory of any sort. For medical advise please refer to your
doctor.
Copyright
The material in this Cyberzine is
copyrighted. Any reproduction without permission of the editors is illegal.
Although the format of this information is electronic, the cyberzine is
subjected to the same copyright regulations that cover any other form of
publication.
<C> Copyright Martin P.
Mintchev/ Kenneth L. Bowes, 1995
FIGURE
A. Combined 4-minute recording of internal and cutaneous gastric electrical
activity: Channels 1-3 are short distance bipolar (SDB) recordings with
implanted electrodes; Channels 4-5 are long distance bipolar (LDB) recordings
with implanted electrodes; Channels 6-8 are electrogastrographic (EGG)
recordings;
FIGURE
B. Three-dimensional plots of 1-hour electrogastrographic signal (2 channels).
FIGURE C. Standard electrode
positions for electrogastrographic recordings.
Electrogastrography
is the cutaneous recording of gastric electrical activity.
Gastric Electrical Activity (GEA) - a simple overview
The electrical activity of the stomach, its interrelations with gastric motor
function, and its role in gastric motility disorders has been the research
focus of many scientists in this century. The works of Alvarez (1, 2, 3),
Alvarez and Mahoney (4, 5) and others (6, 7, 8) in the early 1920s paved the
way for decades of research in this area.
While a great deal of attention has
been directed at understanding the electrophysiological processes in the
stomach in vitro (outside the living organism),
significant efforts have also been devoted to studying these phenomena in vivo (within the living organism).
Gastric electrical abnormalities
recorded in vivo with electrodes implanted on the stomach wall can be related to certain gastric motility
disorders (9, 10, 11, 12). However, such techniques are rarely used because
they are invasive and uncomfortable (10, 11, 12).
Cutaneous recordings of gastric
eletrical activity (GEA), known as electrogastrography
(EGG), would seem to be an avenue for the non-invasive assessment of
gastric motility. Although Alvarez recorded electrogastrographic signals in
1921 (2), only recently has the technique shown practical promise. EGG has been introduced into several
gastrointestinal motility laboratories in the U.S.A., Canada, the Netherlands,
Great Britain, Germany, France, Japan and Australia. Unfortunately, the
diagnostic value of this method is still in question and much new knowledge is
required before clinical disorders can be related to EGG signals with any
certainty (10).
Selected Topics on
Electrogastrography
(this section is under development)
1.
Electrical Phenomena in the Human Stomach (by Martin Mintchev and Kenneth
Bowes)
2. Modeling
of Gastric Electrical Activity (by Martin Mintchev)
3.
Amplification of Gastric Electrical Signals (by Martin Mintchev)
4.
Methods to Assess Gastric Electrical Activity (by Martin Mintchev, Jack
Kingma and Kenneth Bowes)
5.
Accuracy of EGG (by Martin Mintchev, Jack Kingma and Kenneth Bowes)
6.
Derivation of an Objective Method to Assess EGG (by Martin Mintchev and
Kenneth Bowes)
7.
References for sections 1-6