摘要
This paper reports the changes of the EEG of human bodies during saturation ex-posure at different depths to different mixed gases. The results of the research show thatthe most obvious on EEG was the appearance of diffused slow waves, usually θ wavesof 4- 7 times/s, and δ waves of 2- 3 times/s within individual subjects. The EEG changesat 50 m were more obvious than those at 36 .5 m. With the prolonging of time under highpressure, the EEG had some improvements, for instance, the slow waves decreased andthe α waves increased. There was a certain relationship between these changes and thesymptoms which appeared in the human body. The chief factor of the EEG changes isdue to the effect of nitrogen narcosis during the oxygen-nitrogen diving experiment. Inaddition, carbon dioxide retention under the high pressure is also a factor of the EEGchanges, because repeated inhaling of CO<sub>2</sub>-dense mixtures could aggravate the EEGchanges and the reduction of carbon dioxide in humans by hyperventilation could
This paper reports the changes of the EEG of human bodies during saturation ex-
posure at different depths to different mixed gases. The results of the research show that
the most obvious on EEG was the appearance of diffused slow waves, usually θ waves
of 4- 7 times/s, and δ waves of 2- 3 times/s within individual subjects. The EEG changes
at 50 m were more obvious than those at 36 .5 m. With the prolonging of time under high
pressure, the EEG had some improvements, for instance, the slow waves decreased and
the α waves increased. There was a certain relationship between these changes and the
symptoms which appeared in the human body. The chief factor of the EEG changes is
due to the effect of nitrogen narcosis during the oxygen-nitrogen diving experiment. In
addition, carbon dioxide retention under the high pressure is also a factor of the EEG
changes, because repeated inhaling of CO_2-dense mixtures could aggravate the EEG
changes and the reduction of carbon dioxide in humans by hyperventilation could improve
abnormal EEGs. The main changes of the EEG during the helium-oxygen exposure at 302 m
were the increase of θ waves, and even of δ waves, the decrease in α rhythm and the
decline of amplitude of α waves. Increased θ index and decreased α index could be seen
at the depth of 302 m. Under any of the above-mentioned pressure conditions when slow
waves characteristic of abnormal changes appeared in the EEGs, the EEGs could be tem-
porarily improved by photic stimulation, i.e. slow waves disappeared and a waves reap-
peared. When photic stimulation was over, α waves disappeared and slow waves reap-
peared. It was indicated that abnormal changes of the EEG under high pressure were a
kind of temporary and reversible changes of the brain function.
