Characteristics of the Human EEG Reaction to Artificial Hyperbaric Gaseous Environment

Abstract

EEG-reactions of subjects to breathing different artificial gas mixtures were studied at the IBMP Deepwater Diving Facility (GVK-250). The subjects descended to a depth of 2 m relative to the sea level, breathed oxygen–nitrogen and oxygen–nitrogen–argon mixtures for ten days, and an oxygen–nitrogen–argon mixture when descended to a depth of 20 m for seven days. EEG was recorded from six subjects to estimate relative values of the main band powers, global correlation dimension D2 and to perform qualitative analysis of individual EEG patterns. Significant one-way shifts in the EEG quantitative and qualitative parameters were shown by the subjects at a depth of 20 m breathing the O₂-N-Ar air mixture. When they breathed this mixture for ten days at a depth of 2 m, functioning of the brain cortex was almost optimal. Ten days in the hypoxic NO₂ atmosphere did not cause any distinct changes in the EEG spectral parameters.