Remote measurements of the electrical gastric signals - between theory and practice

The paper analyses the gastric signal acquiring with electrodes, placed at few centimeters distance from the gastric tissue. The electrogastrography EGG was accurately extracted as invasive method, by penetrating needles into the stomach walls since 15 years ago. Relatively recent, a non-invasive method, based on skin electrodes on the abdominal region, was investigated as a remote organ test. The technical and medical particularities for the EGG signal recording are presented. The paper presents a versatile solution for the acquiring, filtering and processing of the cutaneous electrophysiological signal recording from the abdominal skin. Low-pass filters coupled to band pass filters are connected in order to abruptly cut higher frequencies than 50-25Hz and to allow the useful signal transmission. The data vectors are recorded by a specialized medical analog platform ADS1298 and transmitted to a mobile PC. This allows a subsequent digital signal processing, followed by a signal characterization.