Comparison of five levels of motion sickness severity as the basis for grading susceptibility

Abstract : The Coriolis (motion) sickness susceptibility index (CSSI) of 275 healthy male subjects was calculated from data obtained by a standardized laboratory procedure at each of five specific levels of motion sickness severity, viz, frank sickness (FS), severe malaise (M III), moderate malaise (M IIA and M IIB), and mild malaise (M I). The stressor value (E factor) of a single standardized head movement associated with each rotational rate of the test chair was adjusted to yield an equivalent CSSI score independent of the endpoint selected. Close agreement among the CSSI scores obtained at each endpoint was found in intercorrelations, test-retest reliability coefficients (N = 30), and frequency distributions that reflected the orderliness and stability in the appearance, ramification, and intensification of the acute symptomatology evoked in progressing from M I to FS. The endpoint M IIA appeared, however, to yield the best balance between subject acceptability and test confidence, and was used without exception to calibrate the motion sickness susceptibility of 250 additional subjects. (Author)