Monitoring of mental performance during spaceflight

Mental performance of astronauts during spaceflight may suffer from both di rect effects of microgravity on perceptual, cognitive, and psychomotor proc esses, and unspecific stress effects on these functions due to high workloa d, sleep disturbances, or the general burden of adapting to the extreme liv ing conditions in space. Early detection of any signs of mental performance impairments seems to be essential for mission success and to prevent obvio us performance decrements in critical mission tasks. One possible approach to this problem is to assess the astronaut's performance-on specific screen ing tests repeatedly during a space mission and to compare the results with a self-referenced baseline established pre-flight. The selection of screen ing tests for this purpose should be guided by three different criteria: 1) their reliability; 2) their sensitivity (i.e., their power to reveal subtl e mental performance changes induced by internal or external stressors duri ng spaceflight); and 3) their diagnosticity (i.e., their capability to reve al the underlying processes that lead to these performance deficits). Based on a discussion of these theoretical issues, first attempts to monitor men tal performance of astronauts during spaceflight by means of short-term lab oratory tasks are reviewed. The results of these studies suggest that, in p articular, perceptual-motor tasks (tracking) and tasks placing comparativel y high demands on attentional processes (e.g., dual-tasks) represent sensit ive monitoring measures. First studies on the diagnositicity of tracking pe rformance decrements during spaceflight suggest that they reflect both micr ogravity-related changes in the sensory-motor system as well as unspecific stress-effects, with the former factor reflected primarily in tracking perf ormance decrements during early adaptation to the microgravity environment.