Investigators
Abstract Technical background There are a number of environmental factors (i.e., background noise, lighting, heat sensitivity, isolation and confinement) during spaceflight that may negatively impact the operational efficiency of crew. Noise increases irritability and contributes to sleep disorders, resulting in a decrease in work productivity (Bayevskiy, and Semenova, 1986; Connors, Harrison, and Akins, 1985). Lighting effects on productivity and circadian rhythm desynchrony have been widely researched on Earth and in space, (Berry, et al 1966; Bluth, 1982). Alterations in sleep-wake cycles, sleep patterns, sleep quality, workload and fatigue can also adversely affect performance (Naitoh, 1969; Santy, et al. 1988). A shift of 6 hours in the sleep-wake cycle precipitated an “autonomic crisis” in a Salyut-5 commander, manifested by weakness, perspiration, and variable blood pressure, (Stepanova, 1986). Arctic and Antarctic research stations, submarines, undersea laboratories, among others, have been studied extensively to find that prolonged confinement causes decrements in psychomotor skills, memory, judgment (Fraser, 1966; Connors, Harrison, and Akins, 1985; Palinkas, et al., 2000). Psychological and emotional factors can also have a detrimental effect on crew performance. During a Skylab mission, performance of crew improved with reduced errors when the crew-ground conflict was worked out (Cooper, 1976). A dramatic decrease in performance capacity on the third day of a Russian space flight resulted from increased psychological stress where quality and accuracy improved with decreasing signs of stress (Smirichevskiya, 1979). Psychological tension, sleep disturbances and psychosensory discomforts (i.e., vestibular-autonomic reactions or space motion sickness, perceptual and sensory illusions) are the most typical states that affect crew members neuropsychological adaptation to flights of up to 15 days in duration. These adverse conditions or states, occurring separately or together, essentially determine the formation of more generalized states (e.g., psychological fatigue or exhaustion) which may occur during extended duration flights (Holland. and Marsh ,1994; Myasnikov, and Zamaletdinov,1996). Cumulative fatigue is indicative of “asthenia”, which describes an abnormal state marked by weakness, increased tendency for fatigue, irritability and disorders of attention and memory (Kanas, 2000). This condition constituted a risk factor with regard to psychological and professional reliability of crewmembers, and has been confirmed by observations of incidences of impaired operational performance and conflict among crewmembers (Shaposhnikov, et al., 1991). Russian scientists have developed a set of methods for describing functional state, the physiological and psychological state during which performance is highest, which can be calculated using both performance and physiological indices. In general, those individuals whose physiological indices were elevated substantially above group means, were also those individuals who performed poorly (Bodrov, et al., 1985). During performance of assigned tasks for a 26-hour uninterrupted period, physiological changes tend to precede associated performance decrements (Epishkin and Skrypnikov, 1986). In a study of sensorimotor performance capacity during the initial period of weightlessness, five cosmonauts decreased the quality of their performance. Simultaneously, heart rate increased from 15-35%. As cosmonauts participated in more sessions, the quality and accuracy of performance increased, with heart rate decreasing to baseline levels. The principal finding consistent within this Russian research is that the combination of physiological measures and performance metrics is a reliable method for evaluating environmental effects of spaceflight on individual crewmembers (Salnitskey, Shevchenko, and Dudkin, 1991). The variety of environmental and endogenous factors of space flight interacts with each other and with performance levels in very complex ways, and emphasizes the importance of assessing multiple variables to evaluate functional state. The methodology of converging indicators, which includes performance variables, mood state scales, symptom reports, and physiological responses, has been found to increase the accuracy of the assessment of motion sickness in ground-based studies (Cowings et. al, 1986; Cowings, Naifeh and Toscano, 1990; Stout, Toscano and Cowings, 1993; Cowings, et al., 2000; 2001) and the space environment, in which components of sleep, circadian rhythms and performance in space were integrated to assess adaptation (Monk, et al., 1998; Toscano and Cowings, 1994; Toscano, Cowings, and, Miller, 1993). Hockey (1986), states that a set of standard indicators is needed that will provide a comprehensive picture of the nature of the adapting system. For this purpose, it is necessary to be able to measure changes in a number of components and examine the overall pattern or “map” as a set of vectors in a multidimensional space. |
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