The body perceives motion through different sensory pathways, including the ears and eyes. The ears detect angular and vertical motion while the eyes help determine the body's position in space, according to the Centers for Disease Control and Prevention. These senses must work together or a conflict can occur leading to motion sickness. Motion sickness occurs in response to real perceived or anticipated movement.
Inner Ear Structure
Although small, the inner ear contains six mechanoreceptive structures. The cochlea transforms what we hear, a mechanical energy, into electrochemical energy the brain can process, while the other five structures function in balance and equilibrium. The bony labyrinth consists of a series of cavities lined by the membranous labyrinth and containing three semicircular canals, the utricle and the saccule. A fluid known as perilymph lines the bony labyrinth while another fluid called endolymph can be found in the membranous labyrinth. The semicircular canals and the saccule function to detect motion.
Sensory Communication
The ears normally perceive motion and the eyes balance the perception by letting the brain know the placement of the body. Motion sickness occurs when the signals received by the eyes do not match the signals received and transmitted by the ears. This unbalance in sensory communication most commonly occurs when movement occurs simultaneously on multiple planes, such as on airplanes or ships.
Types of Motion
Many types of motion can result in motion sickness, including motion felt while traveling in a moving car or boat. Traveling on a large ship commonly causes motion sickness because the sensors in the inner ear feel the motion of the sea, but the eyes do not see this motion from inside. Motion experienced in an amusement park ride, such as a roller coaster, also can cause motion sickness. Perceived motion, such as that felt in a virtual reality simulation ride, sends signals to the eyes without the ears actually sensing the motion, which results in motion sickness.
Contributing Factors
Not everyone experiences motion sickness and those who do might not experience it in all situations. Several factors increase the risk of the onset of motion sickness. Children from 2 to 12 are at increased risk for motion sickness, according to the University of Maryland Medical Center. Those susceptible to experiencing nausea and vomiting also are more likely to suffer from motion sickness, as are those with a heightened sense of fear or anxiety.
Prevention Tips
The best way to deal with motion sickness is to prevent it. When traveling by car, sit in the front seat where the horizon remains in sight. Avoid taking part in activities that take your eyes away from the horizon, such as knitting or reading. When traveling by air, avoid eating a large greasy meal, salty foods or dairy foods, or drinking alcohol prior to the flight. Sitting closer to the front of the airplane also helps prevent motion sickness. On a boat, staying in a cabin on the upper deck or toward the front of the ship helps prevent motion sickness.
