The stability of individual patterns of autonomic responses to motion sickness stimulation.

As part of a program to develop a treatment for motion sickness based on self-regulation of autonomic nervous system (ANS) activity, this study examined the stability of an individual's pattern of ANS responses to motion sickness stimulation on repeated occasions. Motion sickness symptoms were induced in 58 people during 2 rotating chair tests. Physiological responses measured were heart rate, finger pulse volume, respiration rate, and skin conductance. Using standard scores, we examined stability of responses of specific magnitudes across both tests. Correlational analyses, analysis of variance, and a components of variance analysis all revealed marked, but quite stable, individual differences in ANS responses to both mild and severe motion sickness. These findings confirm our prior observation that people are sufficiently unique in their ANS responses to motion sickness provocation to make it necessary to individually tailor self-regulation training. Further, these data support our contention that individual ANS patterns are sufficiently consistent from test to test so as to serve as an objective indicator of individual motion sickness malaise levels.