Prediction of the space adaptation syndrome

Abstract : A study was completed (a) to describe the univariate and multivariate relationships of provocative measures used by the neurophysiology laboratory, (b) to use normative subjects to develop and cross-validate sets of linear equations that optimally predict motion sickness in parabolic flights, and (c) to evaluate the possibility of reducing the number of measurements required for prediction. After describing the variables verbally and statistically for 159 subjects, a factor analysis of 27 variables was completed to improve understanding of the relationships between variables and to reduce the number of measures for prediction purposes. The results of this analysis showed that nine factors account for 100 percent of the common variance and that none of variables are significantly related to the responses to parabolic flights. Using the results of the factor analysis, a set of variables were selected to predict responses in KC-135 flights. A series of discriminant analyses were completed using part of the subjects to develop sets of predictive linear equations and part to cross-validate the equations. Results indicated that low, moderate, or severe susceptibility could be correctly predicted 64 percent and 53 percent of the time on original and cross-validation samples, respectively. Similarly, sickness or non-sickness was 60 and 68 percent correct on original and cross-validation samples, respectively. Predicting vomiting or no vomiting on the KC-135 flights was 73 and 62 percent correct on original and cross-validation samples, respectively.