Personality and coping strategies during submarine missions.

Relations between personality profiles, measured by the Personality Characteristics Inventory (PCI), and habitual coping strategies, measured by the Utrecht Coping List (UCL), were investigated in a sample of submarine personnel and office employees. The predictive validity of these instruments were examined for reported stress, health complaints, and salivary cortisone measures during 3 submarine missions. PCI and UCL were completed before the missions, and questionnaires and saliva were collected weekly. The results showed no significant relations between PCI profiles and coping strategies. Interpersonal orientation, achievement motivation, and habitual coping strategies were predictors for coping during the submarine missions. Problem-directed strategies and interpersonal sensitivity combined with strong achievement motivation were related to low indicated stress from social factors (lack of privacy, interpersonal tension, and crowding) and homesickness. The findings suggest that interpersonal characteristics need to be considered in the selection of submariners and personnel for other military settings in which units are exposed to prolonged stress and isolation.

Psychological reactions during polar expeditions and isolation in hyperbaric chambers.

BACKGROUND: Psychological data from environments that are considered as analog to space was collected from 68 subjects; 18 in hyperbaric chambers, 16 in polar expeditions, and 34 on Arctic stations. The objective was to identify psychological reactions expected in different phases of spaceflights and examine personality variables associated with superior adaptation. METHOD: Helmreich Personality Characteristic Inventory was administered before the isolation. Adaptation to the environment was assessed through a questionnaire once a week. RESULTS: Crews in hyperbaric chambers indicated a steady increase in coping over the isolation. Polar expeditions members reported high aggressiveness and anxiety in the first quarter and an increase in homesickness over time. A personality characterized by strong expressiveness and instrumentality ("the right stuff") predicted superior adaptation in hyperbaric chambers. CONCLUSION: The data suggest that isolation in hyperbaric chambers and polar expeditions should be considered as models for different aspects of the space environment.

Crew compatibility and interaction.

A crew of four (three males and one male) were isolated for 60 days in hyperbaric chambers at DLR, Cologne, Germany. The aim of the study was to investigate how group functioning, relations with ground control, and interaction between crew members would change during isolation. A broad array of methods was used, including analysis of communication, peer ratings, questionnaires, and a post-isolation interview. The main findings are: 1. Group functioning declined at three times, immediately before and after the start of isolation, and in weeks 2 and 5; 2. Conflicts were often focused on project management. 3. Crew members showed a marked tendency to deny team conflicts, making them vulnerable to "group think;" 4. Towards the end of isolation, social factors were given more importance than task-related factors; 5. Lasting antagonism between two of the male crew members were noted, which made one of them withdraw from interaction, while the other one--the most dominant crew member--developed an alliance with the Commander. Several findings in this study are consistent with our earlier results from the ISEMSI study. The existence of several interpersonal issues has been identified, which are also likely to occur during actual space missions. Many of the interpersonal problems could probably be prevented or reduced through behavioral and sensitivity training, composition of crews according to compatibility, and monitoring of group functioning during the flight. We suggest that future simulation studies should be directed towards gaining practical experience in how to influence interpersonal relations in a desirable way. The joint training of ground crew and chamber crew created good co-operation between the two crews, but the adjustment to management requires more experience and new training procedures. The lack of formalized rules caused serious frustrations and negative feelings in both crews towards project management. Data from management and principal investigators were not available, but we suggest that such information should be collected in future simulation studies.

Interpersonal relations during simulated space missions.

The present article derives from two isolation studies performed for the European Space Agency (ESA) as simulations of space travels, lasting for 4 and 9 weeks. The aim was to study how interpersonal relations were affected by time, and how individual characteristics related to conflicts and tension among crewmembers. A broad battery of methods was used, including video-recording, peer-ratings and self-reports. In both studies, group-functioning declined in the middle of the isolation and towards the end of the stay. Dominance and task motivation seemed to be important characteristics for compatibility between crewmembers, and negative relations established early in the isolation remained stable over time. These findings have implications for composition, training, and support of crews for extended spaceflights.

European isolation and confinement study. Mental performance.

Six EMSInauts were confined for 28 days in a hyperbaric chamber complex at a low overpressure. During this period they were repeatedly given four different standard mental performance tests: (1) Operational Test of sustained attention vigilance; (2) short-term memory; (3) visual reaction time; and (4) cognitive evoked brain potentials (N100 and P300). The aim of the study was to determine whether there were any general or specific effects on mental performance during the isolation period. For the simple mental performance tests (operational test and visual reaction time), a distinct learning effect over the 28 days of isolation could be detected. On the more cognitive demanding tasks such as in the short-term memory test, patterns of impairment were found. Of the cognitive evoked brain potentials recorded, the noncognitive N100 wave latency was unchanged throughout the isolation period. The P300 wave latency, related to cognitive functioning, showed lower values in the middle and higher values at the end of the isolation period, compared with the pre-isolation values. Although a few individual, transient impairments of function were noticed in the more demanding tests, it is concluded that the mental performance of the six EMSInauts appeared to remain basically unchanged throughout the isolation phase, both at the group level and the individual level.

European isolation and confinement study. Water and salt turnover.

Intake and output of water were studied in six male subjects from six European countries during 28 days of isolation and confinement in order to assess whether the observed reactions can be compared with those observed during space travel. On the average, the subjects drank 17.5 ml/kg/day fluids. An additional 25 ml/kg/day was recruited from food intake and metabolism. The lowest fluid intake of 11.3 and 12.1 ml/kg/day was shown by two subjects who concurrently lost 3 to 4% of body weight. Three subjects maintained body weight, and one subject gained. A linear correlation existed between the total water output and the fluid intake by drinking. The time series of fluid intake, urine output, and sodium excretion revealed a weekly pattern for these parameters, characterized by low values on Sundays and high values on Fridays. This pattern was most apparent for sodium excretion. Low water turnover rates were seen in the first week of isolation; in the last week the values were above average. In conclusion, it can be said that with respect to the water balance, strong individual differences and time dependent variations (day to day, week to week) of the respective parameters have to be taken into account for the data analysis during such long-term studies.

European isolation and confinement study. Group functioning and communication.

Six EMSInauts were isolated in the hyperbaric chambers at NUTEC for a period of 28 days at 5-msw overpressure. Based on previous studies of analogous conditions, the hypothesis was advanced that group and communication problems could possibly occur during the isolation period, and that this could be partly related to personality aspects. The scientific methods for the present study consisted of the following: (1) the team members were systematically observed through wide-angle cameras, and the activities in the working chamber were taped during the entire isolation period; (2) daily questionnaires regarding group functioning and communication were administered; and (3) post-isolation assessment interviews were given. Results were obtained by analysis of: (1) video tapes from the daily meetings; (2) questionnaires on group behavior and communication; (3) post-isolation interviews; and (4) personality inventories (DMT, Helmreich Test, MMPI). The following observations were made: 1. All team members were able to complete the 4-week isolation period while remaining functioning. 2. The commander became ever more central during the isolation period. Communications went more directly through him and less between the EMSInauts. At the same time he became evaluated less positively by the other EMSInauts. 3. There was a steady increase in emotional responses among all EMSInauts during the isolation period. In particular, there was an increase in negative emotional content. 4. Week 3 was evaluated by the EMSInauts as being the most positive period. They scored themselves then as being very task oriented. 5. The EMSInauts gave a low score to problems with the mission control room personnel, indicating few problems. There were indications of temporary increases during week 2 and at the end of the isolation period. In summary, it can be stated that all team members completed the 4-week isolation in good condition. The commander developed increasing control during the isolation period, which resulted in increasingly negative responses towards him from the other team members. During the isolation period there was an increase in emotional content. In particular, during the last week there was an increase of frustrations. There were few communication problems with mission control, though the scores were elevated in week 2 and on the final two days.

European isolation and confinement study. Workload and stress: effects on psychosomatic and psychobiological reaction patterns.

Six healthy males, the EMSInauts, were isolated in hyperbaric chambers for a period of 28 days at 5-msw overpressure. During that period they had to carry out meaningful operational and research tasks in addition to monitoring their psychological and physiological reactions. The actual workload was evaluated and compared with the planned workload, and its effects on symptomatology and psychobiology. The perceived workload and its effects on psychosomatic symptomatology and on some biological indices were monitored. Thus it was possible to evaluate how the workload carried during 4 weeks of isolation affected the psychological and biological well-being of the six EMSInauts. The following three types of assessments were performed: 1. Workload assessment: The objective workload was calculated based on the schedule which was revised daily, and the actual load calculated by the commander. A workload questionnaire was administered daily after each working session. 2. Psychosomatic assessment: Morning and evening questionnaires were administered daily. The state of health and of anxiety were also evaluated. 3. Biological indices: Cortisol, testosterone, adrenalin, and noradrenaline were determined once a week. In addition, cardiac activity was monitored every day. The workload assessment showed that on the average the planned workload was accomplished in slightly less than the scheduled time. The workload was not perceived as severe in terms of cognitive, emotional, and physical load. The group rated the support received from each other and from the mission control personnel as average, with minor changes during the isolation period. They gave a high rating to the amount of control they had over their activities. Fatigue and tension were scored in the middle range. The psychosomatic assessment showed that there were few symptoms, and these were mostly of low severity. The most common symptom was general fatigue. Furthermore, minor dizziness, headache and light tremor was in some cases reported. The sleep quality was good, but complaints about poor sleep increased somewhat with the passing of time. Few and mostly minor health problems were experienced during isolation. Only one EMSInaut had to miss one day of work due to a bout of flu. The state of anxiety was below that of the general population throughout the isolation period. The biological indices used showed no evidence of stress from the workload handled during the isolation period. The level of the "stress hormone" cortisol actually decreased during isolation. The adrenalin excretion, which tends to go up during acute stress, remained unchanged during this period. Neither was there any evidence of changes in cardiac activity throughout the isolation period.(ABSTRACT TRUNCATED AT 400 WORDS)

[Acute and chronic effects of deep diving on the nervous system]. / Akutte og kroniske effekter på nervesystemet ved dypdykking.

Diving deeper than 180 metres of seawater (msw) will impose neurological symptoms in most divers. Atactic signs and abnormal EEGs were found in five of 18 divers immediately after deep diving. Neuropsychological testing before and after deep diving in 64 divers revealed a reduction in autonomic reactivity (48%), increased hand tremor (27%) and impairment of spatial memory and reduced finger coordination (8%) after the dives. These results had not improved one year later. A follow-up study of 40 divers one to seven years after their last deep dive revealed that the divers experienced more problems of concentration and paresthesia in feet and hands than the controls. Two had had seizures, one had suffered episodes of transitory cerebral ischemia and one had experienced transitory global amnesia after the deep dives. In the future, oil installations at depths below 180 msw should be installed and maintained with remote control and robot technology.

Visual evoked and brain stem auditory evoked potentials in divers.

Visual evoked potentials (VEP) were examined in 14 divers during dives to 360 metres of seawater (msw). All latencies increased significantly with depth. VEP and brain stem auditory evoked potentials (BAEP) were similarly examined in 18 divers before and after these dives. N75 was significantly increased after compared to before the dive, while there was no significant difference in the P100 and N145 latencies. BAEP I-V latency was significantly decreased after the dives. VEP and BAEP were examined in 156 divers and 99 controls. There was no significant difference in VEP. BAEP I-III interpeak latency was significantly increased for the divers, but with no significant changes in I-V and III-V latencies. VEP and BAEP were examined in 26 divers after treatment for neurological decompression sickness. There was no significant difference compared to the control group. The conclusions are that VEP and BAEP change transitorily with influence of hyperbaric pressure, but do not measure major permanent disturbances in the divers' visual and auditory pathways.

Analysis of neurologic symptoms in deep diving: implications for selection of divers.

Eighteen professional divers (age range 24-33 yr, mean 28.3) participated in one simulated dive to 360 meters of seawater (msw) in a helium-oxygen (heliox) atmosphere with equal compression and decompression profiles. All divers were given an extensive neurologic examination before diving. Clinical neurologic symptoms observed during the dives were equilibrium disorder, sleep disturbances, fatigue, nausea, loose stools, stomach pain, tremor, mental disturbances, reduced appetite, and headache. Symptoms were scored individually by each diver. The symptoms were analyzed statistically by factor analysis, which grouped them into four factors. These symptoms are presumably related to functional disturbances in the brain stem and the cerebellum. Factor 3 symptoms (tremor, mental disturbances, reduced appetite) correlated significantly to a history of predive decompression sickness (P = 0.006) and to cerebral concussion (P = 0.023). Three divers were periodically unable to work at bottom due to equilibrium disorder, diarrhea, or nausea. One diver with mild polyneuropathy and slight cerebral atrophy as seen by computerized tomography and another diver with abnormal electroencephalography were periodically unable to work due to equilibrium disorder and nausea, respectively. We advocate that divers with signs of central or peripheral nervous system dysfunction should not be selected for deep diving.

Evoked potential and other CNS reactions during a heliox dive to 360 msw.

Six divers were compressed to 360 msw on heliox. Visual and cognitive evoked responses were performed repeatedly predive, during the dive, and postdive. The evoked response changes were compared with other neuropsychological and neurophysiological results from the dive. The individual diver analysis revealed normal visual evoked responses (P100) for 5 out of 6 divers. The diver with significant increase in P100-latency had more marked HPNS than the others. On the cognitive evoked responses, the P300-waves were not obtainable at the deepest depths (for 4 out of 6 divers) even if the shorter wave forms were normal. The P300-wave was obtainable at 354 msw and 215 msw for 4 divers, and 3 of them had increase in the P300-latency compared with their predive average. There was a significant correlation between P100 change and the sign-index on the other CNS-tests. In conclusion, valid results on the visual and cognitive evoked responses were obtained at pressure. Mild symptoms and signs of HPNS led to normal visual evoked responses, while more marked effects gave significant increases in the visual evoked latency. The more major changes in cognitive evoked responses at pressure, even on minor HPNS-affected divers, indicated that higher cortical functions are affected at high pressures (greater than 300 msw).

Effects of underwater escape training--a psychophysiological study.

The effect of underwater escape training was analysed among 78 participants at the Norwegian Underwater Technological Center (NUTEC), Bergen, in a psychophysiological study. The training caused significant physiological activation. Perceived training effect was found to be inversely related to anxiety during training. Most of the participants developed a positive response outcome expectancy and increased confidence in flying. The learning aspects were versatile and partly dependent on personality factors. A more individualized approach to training is recommended.

Neuropsychologic effects of saturation diving.

Neuropsychologic status of saturation divers was assessed before and after 300-500 msw dives (deep saturation diving--DSD group) and before and after 3.5 yr of ordinary saturation diving (saturation diving--SD group). Average baseline results showed the divers to be slightly superior to nondiving controls. Mild-to-moderate neuropsychologic changes (greater than 10% impairment) were found in measures of tremor, spatial memory, vigilance, and automatic reactivity in 20% of the divers after deep dives (DSD group). One year postdive no recovery was observed except for a vigilance test. In the SD group, 20% of the divers showed greater than 10% impairment after 3.5 yr of ordinary saturation diving. Significant reduction in autonomic reactivity was also found and there was a relationship between low autonomic reactivity before saturation diving and number of greater than 10% impairments. For the whole group (DSD + SD divers), negative correlations were found between saturation experience and results on memory and complex visuomotor tests. Years of diving from first to last examination was positively correlated with number of greater than 10% impairments and with reduction in autonomic reactivity. No similar correlations were found to dive variables after about 3 yr of air diving. The mild-to-moderate changes seen in some divers, therefore, seem to be the effects of saturation diving. Since one deep dive may cause an effect similar to the effect of 3.5 yr of ordinary saturation diving, there is reason to believe that repeated deep diving may lead to more pronounced neuropsychologic impairment.

HPNS effects among 18 divers during compression to 360 msw on heliox.

Heliox compression deeper than 16 ATA can lead to EEG changes associated with confusion and somnolence. In man the symptoms termed the high pressure neurologic syndrome (HPNS) can also include increased tremor, memory problems, dizziness, nausea, and vomiting. In a series of 3 dives at NUTEC, a compression profile developed for operational use down to 360 msw was evaluated. In each dive 6 different divers were compressed to 360 msw on heliox. Neuropsychologic and neurophysiologic testing were performed repeatedly. The HPNS testing revealed only mild effects of the compression. Only 3 divers had impairments of more than 2 SD in peripheral motor function compared to their predive average. Memory was impaired periodically in 2 divers. The same was found for perceptual speed and reasoning. Fifty percent of the divers had an increase of more than 2 SD in postural tremor, but that had minimal effect on their motor performance. Six of the 18 divers had an EEG power spectrum with both alpha band inhibition and theta increase. While the performance impairment was most marked around 240 msw, the EEG changes occurred mainly deeper than 300 msw. In only 1 of the 18 divers marked EEG changes, marked tremor increase, and marked cognitive performance impairment were observed at the same time. Although mild HPNS was observed, the divers were little impaired during the compression to 360 msw. The results confirm that using a compression profile with rates decreasing progressively with increasing depth, and with several intermediate stops, provides fit divers at depth. By using standard batteries of HPNS testing we were able to obtain evidence for the acceptability of this compression profile.