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Development of an Index of Habitability Using Converging Indicators: Physiology, Performance, and Subjective Reports
Investigators
Principal Investigator —
Patricia S. Cowings, Ph.D.
Research Psychologist
Human Systems Integration Division (Code TH)
NASA-Ames Research Center
Moffett Field, California 94035
(650) 604-5724
FAX (650) 604-1484
e-mail: Patricia.Cowings@mail.arc.nasa.gov
Coinvestigators —
William B. Toscano, Ph.D.
Research Psychologist
Human Systems Integration Division (Code TH)
NASA-Ames Research Center
(650) 604-2324
A. Seleimeh Hines, Ph.D.
National Research Council Postdoctoral Associate
(650) 604-3084
Bruce Taylor, Ph.D.
University of Akron, Ohio
(330) 972-5232
Charles DeRoshia, M.A.
Research Physiologist
Human Systems Integration Division (Code TH)
NASA, Ames Research Center
Moffett Field, CA. 94035
(650) 604-5456
Abstract
The purpose of this project is to develop and validate a quantitative method for assessing environmental effects on individual crewmembers during spaceflight. This project will involve analyses of data acquired during previous laboratory tests, field studies and spaceflight. NASA Ames Psychophysiological Research Laboratory has a unique database collected over a 25-year period on approximately 300 people exposed to a variety of environmental stressors, and the effects of both behavioral and pharmacological countermeasures on their stress tolerance. Previous research has shown that the use of converging indicators (physiological and subjective self-report measures) is a significantly more reliable method for assessing environmental effects on performance than any one indicator alone. We anticipate that the deliverable from this project will be a reliable methodology for accurately assessing microgravity effects on individual crew performance and for evaluating countermeasures designed to facilitate adaptation to space and readaptation to Earth.
Teachnical Background
In space, the absence of gravity alone causes unique physiological stress. Significant biomedical changes, across multiple organ systems such as body fluid redistribution, diminished musculoskeletal strength, changes in cardiac function and sensorimotor control have been reported (Sandler and Vernikos, 1986). The time course of development of these disorders and severity of symptoms experienced by individuals varies widely. Space motion sickness (SMS) is an example of maladaptation to microgravity, which occurs early in the mission and can have profound effects on physical health and crew performance. Both the Russian and American space programs have a varied list of human errors and mistakes which adversely impacted mission goals (Bluth, 1982; Connors, Harrison, and Akins, 1985). Continued probability of human exposure to microgravity for extended time periods provides a rationale for the study of the effects of stress, workload, and fatigue on human physiology and performance. And further, because the crew complements of specific space missions will be small in number yet likely to be of diverse nationalities, physical condition and professional backgrounds, it is essential that space human factors measures of habitability be sufficiently robust and effective to determine or predict environmental effects on these specific individuals. The proposed project will developed a new index of environmental effects on individual crewmembers of aerospace missions by mapping the relationship of physiological responses and measures of behavior, (i.e., perception, cognition, subjective reports and performance) through analyses of an existing data base of a large population of human subjects.
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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