Electrogastrographic norms in children: Toward the development of standardmethods, reproducible results, and reliable normative data

Background: Surface electrogastrography (EGG) is a noninvasive technique th at detects gastric myoelectrical electric activity, principally the underly ing pacemaker activity generated by the specialized interstitial cells of C ajal. Interest in the use of this methodology has grown because of its pote ntial applications in describing functional gastrointestinal disorders, par ticularly as a tool in the evaluation of nausea, anorexia, and other dyspep tic symptoms. Methods: Fifty-five healthy volunteers (27 female), ranging in age from 6 t o 18 years (mean, 11.7 years), were studied for a 1-hour baseline preprandi al period and a 1-hour postprandial period after consumption of a standard 448-kcal meal. Recordings were obtained with an EGG Digitrapper or modified Polygraph (Medtronic-Synectics, Shoreview, MN). Spectral analysis by an au toregressive moving average method was used to extract numerical data on th e power and frequency of gastric electrical activity from the EGG signal. Results: The authors present normative data for healthy children and adoles cents studied under a standardized protocol. Mean dominant frequency was fo und to be 2.9 +/- 0.40 cycles per minute preprandially and 3.1 +/- 0.35 pos tprandially, with 80% +/- 13% of test time spent in the normogastric range (2-4 cycles per minute) before and 85% +/- 11% after the test meal. The res ponse of several key parameters to meal consumption was considered, and the effects of age, gender, and body mass index (BMI) on the EGG were sought. Conclusions: There is a postprandial increase in the rhythmicity and amplit ude of gastric slow waves, as other investigators have shown in adults. Key nonnative values are not dependent on age, gender, or BMI. The authors dis cuss limitations in the data set and its interpretability. The authors esta blish a normative data set after developing a standardized recording protoc ol and test meal and show that EGG recordings can be obtained reliably in t he pediatric population. Development of similar norms by investigators usin g the EGG is crucial for future exploration of the validity and clinical ap plication of the EGG. Differences in test conditions of signal detection an d analytic methods influence EGG results substantially, and caution should be used when comparing results across centers.