Hana kai ii: a 17-day dry saturation dive at 18.6 ATA. VI: Cognitive performance, reaction time, and personality...

Measures of spatial orientation, associative memory, general intelligence, arithmetic ability, reaction time, and personal/social perceptions were administered to five subjects during a 31-day saturation exercise. Performance decrements were noted during 17 days of exposure to hyperbaric Hi-O2 at 18.6 ATA. Significant losses in general intellectual ability were noted, as well as trends toward significant losses in other cognitive tests. Reaction time and arithmetic errors increased significantly during the early testing sessions. Performance during a 3-day cold period was equivocal; arithmetic errors increased, but other measures improved or remained constant. Environmental stressors such as fatigue, anxiety, health problems, personal and social adjustment, and aspects of perceptual deprivation were considered to be influential in reducing performance effectiveness.