Human electrogastrograms: comparison of techniques of recording

There are different methods for recording physiologic electrical signals cutaneously. Monopolar recording has been used, by us and by others, to record the basic electrical rhythm of the stomach. In an effort to improve our ability to routinely obtain a recording of the basic electrical rhythm of the stomach, using cutaneous electrodes (electrogastrography), we have investigated different electrode recording techniques, and compared them with monopolar recording. We studied 10 healthy asymptomatic volunteers who were fasting, using each of the techniques while simultaneously monitoring a monopolar electrogastrogram. Three different recording techniques were studied: a Wilson central terminal, comparing alternative placements of the reference electrodes; a Wilson central terminal with a single placement of the reference electrodes, but alternative placements of the active exploratory electrode; and, last, a differential recording technique. We found all of the studied techniques to be superior to monopolar recording in the amount of time a recognizable three/min basic electrical rhythm could be recorded. However, the differential recording arrangement yielded an improvement in percent of recording time so significant that the electrogastrographic signal could be visually discerned to greater than 80%, compared with 37%, of the monopolar recording. Thus, the differential recording technique is far superior for recording the electrogastrogram.