Visual evoked responses and EEG's of 16 divers breathing air at 7 ATA

This study is an assessment of individual differences in electrophysiological response under diving conditions normally conducive to nitrogen narcosis. A group of 16 men made two dives each to approximately 200 ft in a pressure chamber while breathing air. The visual evoked response of the men at depth revealed several decrements; in the response to a slow rate of stimulation, there was a highly significant reduction in a component around 160 ms, and in the response to a rapid rate of stimulation, marked losses in amplitude and increases in variability were found. The latter changes were related to diving experience while the former were not. No significant changes were found in alpha or theta activity in the EEG.