title: Isopower maps of the electrogastrogram (EGG) after total gastrectomy or total colectomy.
abstract: Isopower or topographic electrogastrograms (EGG) correspond to topographic electroencephalograms. Both project the topographic localizations of the spectral frequencies on the abdominal surface or scalp. This paper compares the pre-operative control isopower EGG maps with those of total gastrectomy or total colectomy. EGGs were recorded simultaneously at 27 locations on the epigastro-abdominal surface. Spectral analysis by the maximal entropy method (MEM) was performed and the ensemble means of pre-prandial and post-prandial spectra were calculated. The spectral frequencies were arbitrarily classified into five groups, 1 cycle per minute (cpm) (0-2.4 cpm), 3 cpm (2.5-4.9 cpm), 6 cpm (5.0-7.4 cpm), 8 cpm (7.5-9.9 cpm) and 10 cpm (10.0-12.9 cpm). Maximal power peaks in each spectral group, and electrode locations which were expressed by x-y coordinates were the indicators for making the isopower EGG maps by using a contour map program. Thereafter, the maximal power spots or foci in each spectral group were determined. The pre-operative maximal power foci of the 1, 8 and 10 cpm groups were distributed rather evenly on the epigastro-abdominal surface. Those of the 3 and 6 cpm groups, mainly concentrated in the epigastric region, were absent in almost all patients who had undergone total gastrectomy. The infra-umbilical foci of the 3 and 6 cpm groups completely disappeared after total colectomy. The infra-umbilical foci of the 3 and 6 cpm groups (2.5-7.4) may reflect the colonic activities and the epigastric 3 cpm foci, the gastric activities. The pre-operative maximal power of the 3 cpm foci decreased significantly after total or sub-total gastrectomy.
authors.affiliation: Department of Physiology and Surgery, Niigata University School of Medicine, Niigata 951, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Homma
authors.forename: J
authors.initials: J
authors.lastname: Hasegawa
authors.forename: T
authors.initials: T
authors.lastname: Maruta
authors.forename: N
authors.initials: N
authors.lastname: Watanabe
authors.forename: H
authors.initials: H
authors.lastname: Matsuo
authors.forename: Y
authors.initials: Y
authors.lastname: Tamiya
authors.forename: T
authors.initials: T
authors.lastname: Nishimaki
authors.forename: T
authors.initials: T
authors.lastname: Suzuki
authors.forename: T
authors.initials: T
authors.lastname: Muto
authors.forename: K
authors.initials: K
authors.lastname: Hatakeyama
mesh_terms: D000328:Adult; D000368:Aged; D003082:Colectomy; D004594:Electrophysiology; D019277:Entropy; D005260:Female; D005743:Gastrectomy; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology; D009130:Muscle, Smooth / Q000502:physiology; D011184:Postoperative Period; D019518:Postprandial Period / Q000502:physiology; D013270:Stomach / Q000033:anatomy & histology / Q000502:physiology*