Observations of canal sickness and adaptation in chimpanzees and squirrel monkeys in a "slow rotation room".

I N AN EARLIER experiment s in which human subjects were exposed to bizarre patterns of angular acceleration in the "slow rotation room" (SRR), the syndrome of "canal sickness" was defined. The main symptoms characterizing this syndrome were headache, malaise, nausea, and apathy, associated with pallor, sweating, and often vomiting. Since these symptoms are believed to result indirectly from stimulation of the semicircular canals, the term "canal sickness" was coined to cover this particular type of motion sickness. In the human, adaptation generally occurred after a period of hours or days of constant rotation, the symptoms either gradually decreasing in severity or disappearing? ,3 After cessation of rotation, symptoms reappeared (post rotation effects), but recovery was relatively rapid. To complement the studies otl man, a variety of animals (monkeys, mice, ratst ground squirrels, racoon and possum) were subjected to rotation, and it was found that the squirrel monkey was particularly susceptible to canal sickness. Systematic investigations were carried out on these monkeys and on chimpanzees: The objectives of the present study were to measure the susceptibility of the animals to canal sickness at different levels of Coriolis acceleration, to