| Research Abstract |
In this research, the peristalsis of stomach was selected and quantitative measurement of mental stress in daily life was examined. This peristole was expected to be sensitive to the comparatively weak and chronic mental stress, while heart rate variability is popular for the measurement of strong and transient stress.
In the first research year, a portable digital biological signal monitoring device was developed, which can continue to operate about 3 days. The possibility of the quantitative measurement of mental stress using the electrogastrogram (EGG) was also examined, and an amplifier with high gains (80dB) and ultra low frequency (0 - 0.016 Hz) was developed. In the experiment, EGG change was recorded in some scenes of daily life. As a result, it was proved that the amplitude of EGG increases and the period shortened when mental stress is applied on the subject.
In the second year, infrared light was examined to measure the stomach peristole, and a light measurement system was dev
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eloped. First of all, atony reflection of the stomach for food was measured and the periodic movement was observed one hour after meals, and this light measurement system was shown to be effective to measure the stomach peristalsis.
In the last year, this infrared light measurement system was improved, because light emitting diode has to be lighted as strong as possible, and it became too hot. Then, a new measurement system was developed in which this diode emits light in a short time and at this instance the reflection light is gathered into PC. In the experiment, the following experiments were conducted: Reactive stomach peristole for drinking-water, thermal stress experiment with hand soaking in iced water, and mental arithmetic experiment. Results showed that light luminance was observed to change according to stomach atony reflection when drinking-water, and it became clear that this method could monitor the stomach peristalsis. Abnormal contraction of stomach caused possibly by mental stress was confirmed, though the reaction is different in each subject on the thermal stress experiment and the mental arithmetic experiment. Therefore, it was shown that the measurement of stomach peristole can become an index to the stress evaluation. Less
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