Electrogastrography in healthy subjects. Evaluation of normal values, influence of age and gender

Electrogastrography (EGG) permits measurements of the gastric electrical activity. However, normal values of electrical activity are poorly defined. In addition, limited data are available on the effect of age and gender. Therefore, in 40 healthy subjects (age range: 19-90 years) normal values for several EGG parameters were assessed after an overnight fast for 1 hr in the fasting and fed state after ingestion of a standardized solid-liquid meal. The electrical signals were captured by a pair of surface electrodes sonographically placed on the skin overlying the gastric antrum. The dominant electrical frequency was predominantly in the defined normal frequency range between 2 and 4 cycles per minute (cpm) (P < 0.001) and was higher in the postprandial than in the preprandial period (3.1 cpm vs 2.8 cpm, P = 0.02). The instability of the electrical rhythm calculated by a dominant frequency instability coefficient (DFIC) was postprandially lower than in the fasting state (P = 0.04). The electrical power (amplitude) increased postprandially (postprandial to fasting power ratio = 2.4). To evaluate the influence of age and gender on normal values the subjects were divided into four groups (median age: male, 28 and 69 years; female, 25 and 67 years). The most parameters did not differ significantly between the groups. However, DFIC was different between the groups (P < 0.05), with elderly women revealing lowest DFIC. In conclusion, normal values for several EGG parameters evaluated in this study should be included in the analysis of gastric electrical activity. The magnitude of electrical frequency and power are not influenced by age and gender, whereas the instability of the electrical frequency is influenced by these factors.