Studies on the function of concentration maintenance (TAF). 5. An experimental study on autonomic nervous balance and TAF] (Jap

Abstract

The results of our studies on school examinations, automation work, jet-flight and over-time clerical work at a bank suggested a close relationship existing between autonomic nervous balance and TAF. With a view of clarifying this relationship, we conducted an experiment.The examinees, 12 in number, were exposed to a noise, which was made variable in its tone and sound level within the range of 250∼4, 000c/s and 80∼95 phon, for two hours until a disagreeable feeling was produced in them. In addition to the TAF-test, serum cholin-esterase activity test (Ch-E), galvanic skin reflex test (GSR), Kestner's capillary cold reaction test and mecholyl test were used as autonomic nervous function tests. The post-exposure values were compared to the pre-exposure values, and the results obtained were as follows:1. The comparison of the pre- and the post-TAF-L value, showed a decrease in all of the examinees. Especially in 6 of them, the decrease was even greater than 0.5, which, according to our previous studies, occurs only in a state of obvious fatigue. The pre- and the post-exposure values were on average 1.9 and 2.4 respectively.2. Autonomic nervous function tests.a) Ch-E activity was measured with Hesterin's method in regard to sera taken before and after the exposure. The result was a significant increase, with the average pre-value of 25.5 and the average post-value of 37.5.b) No consistent patterns were seen in the GSR wave-types.c) Kestner's reaction: A piece of ice with a contact phaset of 2.5cm2 was applied to the skin surface of the frontal chest for 3 seconds. The latent period between the removal of the ice and the occurrence of rubeosis, and the duration of rubeosis until its disappearance were measured. The duration of rubeosis showed a significant diminution from 134.5sec, of the average pre-value to 114.7sec. of the average post-value while no consistent changes were seen in the latent period.d) Mecholyl-test initiated by Funkenstein and supported by Gellhorn's experimental and physiological studies, has been variously modified. In this paper, the fall degree (FD) and swing degree (SwD) were computed and the Suwa's index (SI) was also used for comparison. FD showed no consistent changes, but SwD showed a significant increase after the exposure for all of the examinees, with 1.9 for the pre-average and 2.6 for the post-average. This increase correlated with the decrease in TAF-L. Also, the variations in SI in absolute values significantly correlated with the decrease in TAF-L as well as with those in SwD. Except these, no other correlation was seen among the tests.Exposure to a disagreeable multi-tone noise brought about significant changes in the Ch-E activity, Kestner's reaction and mecholyl test, which indicate some changes are taking place in the autonomic nervous function. The noise caused also a decrease in TAF-L. Since this change was ascertained to have correlation with the changes in the mecholyl test, it is presumed that these changes are due to some common factors. It may be thought that stress stimulus such as noise, is projected, on one hand, on the cerebral cortex through the reticular formation and influences the ability to concentrate attention, and causes, on the other hand, disturbance in the autonomic nervous centrum. In summary, the organic communication and mutual influence between the autonomic nervous balance and the concentration ability which are effected through the reticular formation were demonstrated by the close correlation between TAF and the autonomic nervous functions.These results experimentally demonstrate an accurate grasp of mental stress by the TAF test and the reasonableness of its principle.