242 



PHYSCHOPHYSIOLOGICAL FINDINGS 



was present in two men. The individual with the mental slowness and mild confusion was seen 

 at the laboratory a few minutes after completing a two to three hour dive to 200 ft. A repeat 

 evaluation when the diver was rested and had not been diving for a few days was completely 

 normal. This diver's EEG showed an irregular pattern with dominant 4 to 7 cps activity on 

 the first examination which was not present on the repeat examination. 



Neurological changes were found in the postdive examinations in only one man; marked 

 improvement was noted in the man who exhibited the cerebellar findings on predive examination. 



The men were questioned in order to ascertain whether neurological symptoms were pres- 

 ent while they were in the habitat. Sixteen men reported suboccipital, retro-orbital, or gener- 

 alized headaches. For most the headaches were mild, but for three divers, the headache was 

 so severe they were obliged to go to bed. The headaches were most severe on awakening and 

 abated with activity. Three individuals reported that their thought processes were slowed, and 

 two subjects experienced euphoria for the first few days. Sleep problems, getting to sleep as 

 well as staying saleep, were reported by some divers. 



Psychophysiological 



Basal level values were obtained during the initial 15 minutes of both pre and postdive 

 examinations. During this period, the subject was told to relax, but stay awake, and to keep 

 his eyes closed. The basal levels were the average values for each of the variables during 

 this period. Skin resistance values were converted to microohms and will be reported as 

 conductance. Heart rate and respiratory rate variabilities were the average of the variations 

 in rate from beat to beat for one minute. For skin resistance the measure of variability was 

 number of GSRs occurring without any known external stimuli. A similar measure of spon- 

 taneous activity was used for FPR, i.e., the number of vasoconstrictions during this 15-minute 

 period which were not a response to external stimuli. 



Autonomic responsiveness was evaluated by measuring the response to the flickering light. 

 The response to the first flicker as well as the average response to the 21 flicker presentations 

 was scored. The flicker was presented at each frequency from 5 to 20 for 30 seconds, after a 

 30-second off period between frequencies. Spontaneous GSRs and FPRs were not counted while 

 the flicker was on. More complete scoring procedures are presented in the reports by Johnson. 



The pre-post basal values are listed in Table 19. Since there were no statistical differ- 

 ences among the three teams on any of the predive or postdive measures, they were combined 

 into one sample. As four men from Team 1 were not available for predive examination, the 

 pre-post comparisons are based on 24 subject examinations. 



Table 19 

 PREDIVE -POSTDIVE AUTONOMIC BASAL LEVEL VALUES 



