Cardiovascular and respiratory responses during a complex decision-making task under prolonged isolation

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 analysis and evaluation of the data, psychologists at mission control may decide to provide information to the crew concerning potential individual or intragroup overload or stress problems, and to implement specific supportive measures. The effectiveness of the supportive activities should be closely monitored by mission control. Future work should also be aimed at developing expert-systems, which will enable the crew to maintain an appropriate degree of inflight biobehavioral self-regulation by providing a range of support techniques, like biofeedback, coping techniques against individual and group stressors, work/rest and sleep/wake schedules, and emergency procedures.