The role of motion sickness in predicting anticipatory nausea.

Susceptibility to motion sickness has been demonstrated to be a predictor of anticipatory nausea in cancer patients receiving chemotherapy. However, previous research did not test whether motion sickness increases anticipatory nausea only by increasing the base rate of posttreatment nausea and vomiting (which has traditionally served as the unconditioned stimulus in the conditioning model for anticipatory nausea) or, alternatively, whether motion sickness might facilitate the association of external stimuli to posttreatment nausea and vomiting. Using two different analytic approaches--a series of logistic analyses that controlled for drug-induced nausea and vomiting following the initial injection, along with an event history analysis which allows for updating on the posttreatment nausea and vomiting factors--motion sickness was found to be an independent predictor of anticipatory nausea. Further, the predictive power of motion sickness is also independent of the effects of pretreatment anxiety, taste during injection, and age.