Visualized Quantitative Evaluation of Gastrointestinal Activity in Healthy Volunteers Using a Noninvasive Single-Channel Electroamplifier

Background. Electrogastrography and electroenterography are noninvasive methods for measuring gastric and intestinal electrical activities, respectively. Few studies have measured electroenterography in healthy humans; however, no studies have measured electrogastrography and electroenterography simultaneously. This study was performed to provide basic electrogastrography and electroenterography data for comparison with future studies in patients. Methods. Simultaneous preprandial and postprandial measurements of electrogastrography and electroenterography were taken for 30 min each in 50 healthy volunteers. Power spectrum analysis was performed to calculate dominant frequency, dominant power, and power ratio. Results. Gastric and small intestinal dominant frequencies were not significantly different between preprandial and postprandial periods. In preprandial and postprandial periods, normogastria was seen in 49 (98%) and 44 (88%) patients ( $p=0.063$ ), bradygastria in 1 (2%) and 6 (12%) patients ( $p=0.063$ ), and tachygastria in 0 (0%) patients, respectively. Dominant power was significantly increased in the stomach (828 [460–3203] μV2 vs. 1526 [759–2958] μV2, $p=0.016$ ) and small intestine (49 [27–86] μV2 vs. 68 [37–130] μV2, $p<0.001$ ). The power ratio was 1.6 (0.9–2.5) in the stomach and 1.4 (1.0–2.5) in the small intestine. Body mass index showed a negative correlation with the stomach and small intestinal dominant power in preprandial and postprandial periods ( $r_s=-0.566$ , $p<0.001$ ; $r_s=-0.534$ , $p<0.001$ ; $r_s=-0.459$ , $p<0.001$ ; and $r_s=-0.529$ , $p<0.001$ , respectively). The Bristol Stool Form Scale correlated positively with the small intestinal power ratio ( $r_s=-0.430$ , $p=0.002$ ). Conclusion. There was no change in frequency in the stomach or small intestine, but power significantly increased in both the stomach and small intestine.