Incomplete Relationship between Dominant Power of Electrogastrography and Gastric Myoelectrical Activity in Patients with Functional Dyspepsia

Background ＆ Aims : The aim of this study was to investigate the change of dominant power with observation of gastric myoelectrical activity and its parameter linkage in electrogastrography. Methods : Electrogastrography was performed on a total of 123 subjects (113 patients with functional dyspepsia, 10 healthy controls) for 30 min in fasting state and 50 min in postprandial state. Average myoelectrical activity per frequency and accumulated electrical activity of 5 min duration in each bradygastria, normogastria, and tachygastria were measured at the moment of frequency switchover of slow wave. Assumed parameter linkages were also investigated among dominant frequency, ％ of normal regularity, and dominant power (or power ratio). Results : Average myoelectrical activity per frequency was highest in bradygastria (mean 1.10-1.47 Volt/s), next highest in normogastria (mean 0.50-0.82 Volt/s), and lowest in tachygastria (mean 0.44-0.47 Volt/s). Average accumulated myoelectrical activity was highest in normogastria (mean 114.90-126.29 Volt/ss), next highest in tachygastria (mean 71.02-90.00 Volt/ss), and lowest in bradygastria (mean 12.93-51.94 Volt/ss). Significance of parameter linkages were noted in dominant frequency (p< 0.01) and in ％ of normal regularity (p< 0.01), but not in dominant power in case of frequency shift from bradygastria to normogastria (p=0.376). Conclusion : Dominant power is not a parameter that reflects the gastric myoelectrical activity related with only gastric contraction. Bradygastric dominant power does not follow the inter-parameter linkage of electrogastrography for gastric motility assessment.