TEN-MINUTE RHYTHM IN ELECTROGASTROGRAM AND ELECTROENCEPHALOGRAM UNDER MENTAL STRESS

Abstract

In order to clarify the relationship between gastric electrical activity and brain activity, an electrogastrogram (EGG) and electroencephalogram (EEG) were recorded and analyzed simultaneously. The amplitude rhythm derived from the EGG was investigated, in addition to the alpha wave band rhythm of the EEG. The data obtained from 20 healthy female subjects with a mean age of 22.6±3.6 under mental stress was analyzed and the following parameters were extracted; 1) EGG period, 2) EGG amplitude (A-EGG), which was estimated by the least-squares-cosine spectrum method; and 3) the percent of the EEG alpha wave band (α-EEG). In 20 subjects, the mean value of the EGG period was 20.0 ± 0.8 sec. Ten-minute rhythm both in α-EEG and in A-EGG was observed during the study, and it was especially increased during mental stress. In 11(55%) subjects, the 10-min rhythm of A-EGG and α-EEG increased simultaneously during stress testing. Brain and gastric activity are suspected of having a close relationship with the 10-min rhythm.