Advances in space biology and medicine最新文献

The aim of this study was to investigate changes in the psychological state of the crew members and the needs for psychological support during prolonged isolation. For the purpose methods employed that have been widely used in psychological evaluation during Soviet spaceflights. Communication between Commander and Crew Interface Coordinator (CIC) was analyzed. Crew disposition was observed and analyzed for information about the process of group formation and the role of each crew member in this process. Operation of the CIC's was investigated for evidence of a psychological support function. During isolation certain adaptive changes in communication took place: (1) use of unplanned contacts and intensive contacts with a preferred ground crew member, (2) resistance to penetration in the life of the crew (increase of aggressive statements and self-justifications, reduction of report length and claims), and (3) closing communication to "outsiders" by using a special code and decreasing discussion of problems. A process of group formation was noted in the course of isolation, but the final structure of the group was not stable. The relations of subjects B, D and G were crucial in the creation of an effective crew. The woman in the crew was never involved in conflicts and acted as a peacemaker. The crew regarded the communication channel between Commander and CIC as belonging to the entire crew for expressing feelings about crew relations, administration and services, and the CIC can provide needed psychological support, confirming earlier experience from Soviet simulated and actual spaceflights.

A subset of the AGARD-STRES battery including memory search, unstable tracking, and a combination of both tasks (dual-task), was applied repeatedly to the four chamber crew members before, during, and after the 60-day isolation period of EXEMSI. Five ground control group members served as a control group. A subjective state questionnaire was also included. The results were subjected to a quantitative single-subject analysis. Electroencephalograms (EEG) were recorded to permit correlation of changes in task performance with changes in the physiological state. Evaluation of the EEG focused on spectral parameters of spontaneous EEG waves. No physiological data were collected from the control group. Significant decrements in tracking ability were observed in the chamber crew. The time course of these effects followed a triphasic pattern with initial deterioration, intermediate recovery to pre-isolation baseline scores after the first half of the isolation period, and a second deterioration towards the end. None of the control group subjects displayed such an effect. Memory search (speed and accuracy) was only occasionally impaired during isolation, but the control group displayed a similar pattern of changes. It is suggested that a state of decreased alertness causes tracking deterioration, which leads to a reduced efficiency of sustained cue utilization. The assumption of low alertness was further substantiated by higher fatigue ratings by the chamber crew compared to those of the control group. Analysis of the continuous EEG recordings revealed that only two subjects produced reliable alpha wave activity (8-12 Hz) over Pz and, to a much smaller extent, Fz-theta wave activity (5-7 Hz) during task performance. In both subjects Pz-alpha power decreased consistently under task conditions involving single-task and dual-task tracking. Fz-theta activity was increased more by single-task and dual-task memory search than by single-task tracking. The alpha attenuation appears to be associated with an increasing demand on perceptual cue utilization required by the tracking performance. In one subject marked attenuation of alpha power occurred during the first half of the confinement period, where he also scored the highest fatigue ratings. A striking increase in fronto-central theta activity was observed in the same subject after six weeks of isolation. The change was associated with an efficient rather than a degraded task performance, and a high rating of the item "concentrated" and a low rating of the item "fatigued." This finding supports the hypothesis that the activation state associated with increased fronto-central theta activity accompanies efficient performance of demanding mental tasks. The usefulness of standardized laboratory tasks as monitoring instruments is demonstrated by the direct comparability with results of studies obtained from other relevant research applications using the same tasks. The feasibility of a self-administered integr

The Homeostat test system was used to determine the interaction effectiveness of the chamber crew during isolation. The group had a complex and unique structure, reflected in the fact that all four subjects expressed considerable leadership activity. The course of the Homeostat task solution parameters testifies to the formation of an intergroup communicative net, which was not completed. This phenomenon was accompanied by emotional tension in the group. The individual contributions to the interaction were investigated. The crew represents a small group with a complex communicative structure. This was due to the presence of above normal leadership activity in all four crew members. The complex course of the leadership activity parameter and the presence of elements of group management allow us to label the crew as a complementary group, which is capable of coping with a wide range of tasks in problem situations. At the same time, the complex group structure caused a certain level of emotional tension in the group. This tension was drained to the outside world by conflicts with the project management. Subjects B and H played a positive role in the reduction of intergroup tension.

Self-administered psychophysiological assessment during a mission is not only feasible, but yields reliable data that can be related to mission demands in a meaningful way. The unique methodology that has been employed during the EXEMSI campaign, may be of great promise for the development of techniques that provide daily monitoring of physiological cost of mission demands. This approach can thus be used for obtaining a better understanding of problems that can arise with regard to the functioning of individual crew members. The response profiles of the individual crew members showed remarkable quantitative and qualitative differences during isolation. Due to the limitations of this study, these differences could by no means all be explained in terms of mission demands, operator workload or other relevant parameters. However, the findings do seem to permit some tentative conclusions. In subjects B and D the cardiovascular response profiles suggested that cumulative stress effects emerged, in particular during the second part of the mission. It is important to note that both subjects carried specific responsibilities for the success of the mission, and that there was evidence for a conflict between them. Concerning the question which physiological measures are most appropriate for in-mission psychophysiological assessment, these results can appear to imply that cardiovascular measures yield more valid information about the effects of mission demands that respiratory measures. However, it should be noted that important aspects of respiratory activity, namely, respiratory volume measures and ventilation, could not be reliably determined in this study. Therefore, definitive conclusions concerning the choice of measures wait until the validity of the measures has been more extensively evaluated. Although the methodology that was developed for this study appears to be promising, it is obvious that its value can only be properly assessed when the physiological findings are correlated with behavioral, performance and subjective data. An extensive analysis of the covariation of the daily variations in physiological response, performance measures, and subjective assessments of workload and mood, is currently in progress in collaboration with Hockey and Sauer. Finally, if the usefulness and validity of this type of in-mission self-administered psychophysiological assessment are confirmed in ongoing and future studies (e.g., the 1994 HUBES mission), protocols will have to be worked out for practical implementation during actual spaceflights. In this regard, it has been advocated that psychophysiological monitoring techniques should include feedback and support policies, make crew members aware of potential risks for breakdown, and enable them to take appropriate measures when necessary. Initially, this can perhaps best be realized by procedures which include a data-link between the spacecraft and ground mission control. On the basis of ground-based ana

In summary, the results provide several lines of evidence for the assumption that confinement and isolation for a period of 60 days attenuate attentional capacity differentially during auditory classification: the extraction of information from low probability events, but not from high probability events, is decreased by attentional limitations. With the advent of automatic control systems there is an increasing number of operations which require the monitoring of information sources for low probability critical stimuli for extended periods of time. Given the functional similarities of the task employed in this study and the monitoring tasks in practical settings, the results of this study should be considered as a human factor concern for control operations taking place under conditions of confinement and isolation.

The effects of various space scenarios on the circadian system and alertness were investigated. The study of the circadian system under various conditions is important because core body temperature and many other physiological parameters (e.g., hormone levels) exhibit prominent circadian variation. The circadian system has a direct influence on the sleep-wake behavior and thus on performance. Alertness is an easily accessible subjective parameter which is strongly linked to cognitive performance. Simulation of alertness for different sleep-wake schedules may help to delineate crucial phases during missions and to plan counteractions. Although the level of alertness can be accounted for by the combination of circadian and homeostatic processes, additional factors such as motivation or excitement play a role.