The ability of man’s brain can be affected through multiple factors during a stay in space: through weightlessness and its affects on the human body, the changes of the sleep-wake rhythm and through intensive work-related stress. It is about higher and highest brain efforts. Examples are the co-ordination between visual perception and movement, the visual-spatial perception and processing, language, memory and considerable control functions of the brain.
The problem in capturing and predicting the psychological state is not new in spaceflight psychology. Psychological health guarantees the normal function of all cognitive abilities. Characteristic so-called acute periods of adaptation in weightlessness for the first two to three days of flight were detected during examinations of the cosmonauts during the first manned spaceflights with VOSTOK. These observations were also noted in the seventies and eighties during the execution of the INTERKOSMOS program on the SALYUT and MIR stations. In this phase, the reaction time and operation accuracy as well as the coordination and time recording is reduced and disturbed. Normalisation comes into effect from the 5th to 7th day of flight again.
With the start of modern computer technology, examination methods were improved considerably. Within the framework of the COGIMIR experiment, computer methods for the examination of psychological functions (perception, psychomotricity, working memory, etc.) and a test program were developed during the preparation and execution of the AUSTROMIR project (Austria, 1989-1991). The brain performance of an Austrian cosmonaut during his 6-day stay in space was recorded and tested by Russian cosmonauts during his 4-6 day on the MIR space station. A connection between the cognitive capability and the psychological state was determined. This discovery was of importance both for space medicine as well as for clinical medicine (therapy and rehabilitation, sport medicine, etc.). The progress of the examinations was therefore desired in many ways, and the COGIMIR-2 experiment is the logical continuation of the examination regarding this area of space psychology. It connects the knowledge already won and the possibilities that this new methodology offers.
The goal of the COGIMIR-2 experiment was the recoding and monitoring of selected cognitive functions und normal conditions, as well as under the effects of factors of a long-term flight in space. The examined items were the cognitive processes that play an important role during the practical tasks in space, i.e.:
- Functions of attentiveness, state of wakefulness and the executive system, as well as
- So-called visual-spatial functions.
Thereby, it was assumed that the influence of environment-related, work, psychological and stress-related factors of a long-term spaceflight can change the cognitive performance and this change can be registered and measured with the help of the methods developed.
Thus, the performance-reducing factors are: body adjustment to weightlessness, the appearance of sickness symptoms, as well as a row of psychic stress-factors like, for example, isolation, sensory deprivation, disturbed sleep-wake rhythms, stress through mental exhaustion and affective components. Even the re-adjustments observed in the post-flight phase can be associated with mental performance changes. Comprehensive studies about the problem area of monitoring mental performance during and after long-term flights, and underlying their objective measuring methods, are not known in current literature.
COGIMIR-2 analyses the cognitive performances of the cosmonauts before the spaceflight, during the stay on the space station and after return to earth.
The examination methods used in the COGIMIR-2 project had the following tasks:
- The perfection of the methods developed for the capture of cognitive functions within the AUSTROMIR framework,
- The execution of computer tests with psychological test programs and the recording of time and accuracy parameters during the solving of test tasks in various flight stages,
- The examination of the function of frameworks during the optical perception in the mechanism of cognitive performance.
Functionality, Measuring principle
All tests were carried out with the DATAMIR computer system. The system consisted of a central unit, a monitor for the stimulus processing and a keyboard for the entering of response reactions. The tasks were supplied in the form of optical stimuli by the computer. The cosmonaut’s response was carried out by pressing a key on the keyboard. The accuracy and the speed during the entry and processing were recorded as test variables. The goal of all the tests was to react as accurate, but quickly, as possible. No feedback about the levied performance was offered to the cosmonaut. The test stimulus during the STROOP 2, LINE 3, MROT and DOTMIR tests was presented in random sequence in order to avoid a learning effect. The test sequence was kept for all examinations. The examination took about 25 minutes.
The MEL software system used in the project is commercially available. But all the tests were developed specifically for the tasks contrived. Apart from the planning and development of the software, the establishing of examination processes also encompassed a comprehensive trial. During the development phase spanning many weeks, numerous healthy subjects having similar age and education were tested with prototypes of the test. These examinations took place under normal conditions as well as unilateral temperature changes, and led to a customization of the tests with regard to duration, difficulty and other test-specific properties of examination conditions with the involvement of the cosmonauts. The test program consisted of five parts: SREACT, STROOP 2, LINE 3, MROT and DOTMIR.
A monocular device was manufactured as an addition to the software. This was a pyramidal attachment whose base could be fixed to the monitor screen and its tip could be placed on spectacles-shaped observation slit fixed on the subject’s head. The tube was constructed to be foldable in order to save space during transport and met the technical and material-specific requirements of a space-worthy device.
The purpose of this device was to protect the optical background during the examinations on the monitor, so that the environment did not serve as a visual reference. The working hypothesis for the deployment of this device (tube), from a comparison of examinations with and without the tube, was to record the functional meaning of the optical background as a visual reference and orientation system during two visual-spatial tests.
The monocular device (tube) used by HM 16 and 17 after its completion and verification. The tube was deployed by the long-term cosmonauts from the 6th flight examination (first on 22.8.1994). The tube was only used for the visual-spatial tests LINE 3 and MROT because no view towards the keyboard was needed for these processes. In order to facilitate a direct comparison between tests with and without the tube, the examinations were periodically executed in pairs (each examination process with the tube followed by another one without the tube after 24 hours).
Shared equipments of the Austrian payload
Results of the process examination from HM-15, HM-16 UND HM-17
Significant performance differences in all tests between the measurements in the reference phase, as well as the flight and post-flight phase resulted. The majority of performance changes consist of the reduction in the cognitive performance parameter. Practically, all subjects exhibit performance changes; no subject is excluded from this phenomenon. Many performance changes were particularly encountered in the tests STROOP 2, MROT and DOTMIR. The distribution pattern corresponds to the more difficult and therefore more sensible examination processes.
Performance reductions come into effect mostly in the first 2-3 weeks after the start and mostly decrease in scope. Far less performance reductions can be found, even if less defined, in the course of the flight months 2-4, and even after the landing where they are detectable at least for a week. Performance improvements show a low scope during the flight, but more often after the flight. The performance reductions observed affect the functions of attentiveness, vigilance and adaptation capability of the human brain as well as the so-called visual-spatial functions that are required to process spatial-visual stimuli quickly and efficiently (e.g. angle sizes, the relative localisation of optic impressions, or rotated visual stimuli).
Results of the long-term cosmonauts
The same analysis methods were used during the results of the long-term cosmonauts. However 8 (instead of 4) flight measurements were included in the regression equation and therefore significance level of p < 0.005 was determined. The executed regression analyses also show a significant effect of working accuracy (AC) and the repeated measurements (SESSION), lower even the test-specific variables (ISI, CONGR, DIFF). The vast amount of performance changes consist of significant performance losses that are even subsumable days after the landing.
Similar to the subjects of HM-15, HM-16 and HM-17, a maximum of performance loss was shown in the first three flight measurements, afterwards a harmonization reference data level was found. A performance increase of the psychomotor reaction time (SREACT) was also found in the flight measurements F3, F4 and F5.
Results from the application of the monocular device
Four subjects used the tube during their whole flight time. Long-term cosmonaut Poljakov first used the device from the 6th flight examination. The statistical rating was carried out with the help of pair comparisons between the execution with vs. the execution without the tube. MRTO and LINE 3 were used as tests. A performance change due to the tube usage was shown in one-third of the examinations. The results of the comparison with/without device are not unique to evaluate. The performance without the tube was better than with the monocular device (numerical proportion without vs. with = 14:8) in the majority of the comparisons. A subject (HM-16) showed, without exception, better performances with the tube, two persons (HM-16, HM-17) were better without the tube. The long-term cosmonaut and a further person (HM-17) showed alternating good performances with and without the monocular device.
The COGIMIR-2 project led to the creation of a first data collection that facilitated the problem of capturing and understanding evaluating cognitive performances during long-term flights. While a series of cognitive functions within short space stays are barely hindered, sojourns with duration of more than 8 days can lead to mental performance hindrances. Despite many difficulties during the execution of the project, it has been successful in achieving the project goal and answering the main questions.
The results won are the experimental confirmation of the known fact that the expenditure of time for work in the cosmos doesn’t correspond to the existing standards that are planned for the earth. This is confirmed by the teams time and time again. This is not about the specifics of work organisation in weightlessness, but about the formulation of functional requirements of cognitive performance capability limitations. The accomplishment of a professional task during the normal process of a flight program will not be disrupted. However, under certain conditions (increased stress, work at night, unforeseeable situations, etc.), additional risk factors leading to the reduction of psychological reliability can appear.
Although final conclusions can be first made after the continuation of quantitative data analysis, some important moments for the practice of medical flight care can already be formulated now, especially:
- The cosmonauts’ information in the pre-flight stage,
- The use of recommended test methods (after the corresponding adaptation) in the medical control system,
- The computer-support verifications of mental performance and reaction capability allow for an evaluation of cognitive capacity and deliver a valuable process control.
An actual, albeit not a new question of the standardization of tasks in the cosmos is to be discussed, especially with regard to the ISS space station, is also on basis of examinations from COGIMIR-2. It can be further retained that COGIMIR-2 offers measuring instruments that are suitable for testing and comparing cognitive performances in a periodical process relevant to space-flight.
The during COGIMIR used testsoftware included the following programs, which were installed on the main computer DATAMIR, on which the experiment also was taken out:
- evaluation on a simple reaction (SREACT)
- reproduction and realization of time intervalls (MROT)
- evaluation of the attention and the operative memory (STROOP 2)
- evaluation of the two-dimensional visual-spatial cerebration and cognition (LINE 3)
- determination of the spatial funktional memory (DOTMIR)
Univ.-Prof. Dr. Franz Gerstenbrand (institute manager)
Univ.-Doz. Dr. Thomas Benke (project manager)
all: University Clinic for Neurology, Innsbruck
Mag. G. Steinwender
all: Institute for Applied Physics of the university Innsbruck, Innsbruck
Dr. O. P. Koserenko
all: IMBP (Institute für Biomedical Problems), Moscow