Producing Worst Nausea

Walter Johnson examined the question of what kinds of motion would cause the worst motion sickness. "This research culminated in a new finding, an essential finding, as to how the inner ear is maximally stimulated to produce nausea," he said. "We showed that the inner ear acts like a gyroscope. If you spin it in one plane and tilt the gyro in another plane, forces are set up to produce a stronger stimulus that is very nauseating. Say you’re in boat or plane that’s pitching up and down and your turn your head sideways—that’s the worse thing you could do. It’s more effective in causing nausea than anything."

The researchers invented diabolical machines that "would produce these terrible effects on people," said Johnson, who created a device that produced vertigo by spinning test subjects around like a top. Later, another machine, called the Precision Angular Mover, was developed; it rotated test subjects around all three axes—pitch, yaw and roll.

For vertical motion (heave), oscillation at a frequency of about 0.2 hz is the most provocative. (http://www.dizziness-and-balance.com/disorders/central/motion.htm)

http://www.space.gc.ca/asc/eng/astronauts/osm_aviation.asp