Mild eustachian tube dysfunction, such as blockage or edema secondary to upper respiratory infection, may cause the individual to use more force than normal. This increases the pressure in the middle ear, and certainly may cause enough pressure build-up to stimulate the vestibular organ. 5 Motion Sickness Motion sickness is a condition characterized by, nausea, cold sweats, vomiting, and pallor, which is caused by exposure to perceived motion of which the person is unfamiliar with. 6 Other symptoms of motion sickness that are not always recognized are, belching and flatulence, which lead to the development of nausea. Drowsiness is another important symptom of exposure to unfamiliar motion, though not necessarily a direct symptom of motion sickness.
Motion sickness tends to be caused by the mismatch of signals to the brain.
Two main types of motion cue mismatch can be specified according to the sensory system involved. For example, one theory states that signals stimulating the vestibular organs do not match with the visual stimulus. Another theory deals with the fact that the brain has information stored as to the effect of specific force applied to the body. If the force causes a familiar effect then all is well. If the force causes a different effect than anticipated, and for an extended period of time, motion sickness will most likely develop.