The significance of electrogastrographically determined amplitudes--is there a correlation to sonographically measured antral mechanical contractions?

Cutaneous electrogastrography (EGG) allows the measurement of gastric electrical activity. An association of EGG with gastrointestinal motility disorders has been shown. Abnormalities of electrical rate or rhythm are accepted as the most important parameters in EGG. However, the reliability of the magnitude of electrical amplitude in the assessment of motility is discussed controversially. Therefore in a prospective study we investigated the relation between amplitude and antral contractions by means of ultrasonography. 8 healthy volunteers (4 men, 4 women, 24-31 years) ingested 400 ml carbonated mineral water after an overnight fast at two separate study days. Over a period of 10 min preprandial and 10 min postprandial small and intense antral contractions were measured employing sagittal antral planimetry. Simultaneous amplitudes were determined during contractions and at 1 min intervals (average amplitude) by cutaneous electrogastrography. Data were analyzed by Wilcoxon's rank sum test and Spearman rank correlation test. The coefficient of variation of the postprandial/preprandial amplitude ratio was nearly two times greater between subjects than between recordings in the same subject, which reflects a moderate intraindividual reproducibility. We found a significant increase in the average amplitude postprandially (p < 0.05). Although postprandial contractions (n = 243) predominated preprandial contractions (n = 127) significantly (p = 0.02), no significant correlation between the number of contractions and the average amplitude existed (R = 0.1; p = 0.7). Moreover the average amplitude did not differ from amplitudes during intense and small contractions significantly (p = 0.7; p = 0.1). The magnitude of the amplitude measured by EGG does not correlate with the mechanical gastral activity significantly.(ABSTRACT TRUNCATED AT 250 WORDS)