Electrogastrography in healthy children: evaluation of normal values, influence of age, gender, and obesity.

Electrogastrography (EGG) is a reliable technique to record gastric electrical activity. However, the normal values of electrical activity in children and the effects of age, gender, and body mass index (BMI) are not well defined. To evaluate these items, EGG signal was picked up before and after a meal in 114 healthy children (age range: 6-12 years) by means of a pair of cutaneous electrodes sonographically placed on the abdominal surface. The dominant frequency was prevalently found in the 2.0-4.0 cpm range (P < 0.001). A significant difference was found comparing the pre- and postprandial instability coefficient of dominant frequency (P < 0.05). The EGG power increased postprandially (power ratio = 3.6), and the power ratio was not correlated to the approach of the wall of the gastric antrum to the abdominal surface (Spearman r = 0.0045, NS). In obese children, the postprandial pattern in response to a mixed test meal containing carbohydrate as the major caloric source was similar to that recorded in normal-weight children. EGG parameters were not affected by age and gender apart from a significant difference in the postprandial instability coefficient obtained from the "girls > or = 9 years" group compared to the "girls <9 years" and "boys > or = 9 years" groups (P < 0.05). In conclusion, in children 6-12 years old, EGG parameters are not affected by BMI in response to a mixed test meal. Gastric electrical rhythm and rate, and gastric power are not influenced by age and gender, whereas the instability coefficient seems to be influenced by these factors. The normal values of the EGG parameters evaluated in this study should be introduced in the analysis of gastric electrical activity for an effective interpretation of the EGG signal from children with functional or organic diseases.