Summer vacation season brings distress to a number of people who suffer from motion sickness. Motion sickness causes a variety of symptoms, including queasiness, sweating and pale skin color. Some people also experience fatigue and, occasionally, vomiting.
We still don’t know why people get motion sickness, but the circumstances that produce the condition are well known. Motion sickness occurs when the brain receives input about the orientation and movement of the body that differ from those that are expected. For example, when reading a book in a car, our eyes tell us that the body is not moving while receptors in the inner ear, which are part of the vestibular system, tell the brain that the movement is occurring. These contradictory senses can trigger motion sickness. However, we don’t have to be moving to get motion sick. People watching a movie can get motion sick, too, as movement on the screen signals to their brain that they are moving, but the vestibular system tells them they are stationary.
Input from the inner ear seems to be a key component in producing motion sickness, as people with damage to the inner ear on both sides cannot be made motion sick. Some people are also more likely to get motion sick than others, such as those who suffer from frequent migraine headaches.
How can you prevent motion sickness? A number of drugs have been used to treat the condition, including over-the-counter medications such as Dramamine. But these medications tend to cause drowsiness. Other treatments, such as wristbands that apply pressure at acupressure points are available, and some people claim they work well. However, most scientists think that such treatments provide only a “placebo effect”: the patient expects to feel better, and thus they claim that they do.
Perhaps the simplest treatment for motion sickness is avoiding the misleading sensory cues that produce the condition. Drivers of vehicles rarely get motion sick because they focus on the road and get both visual and vestibular cues that they are moving. People on boats or planes tend not to get motion sick if they look to the horizon instead of focusing on the inside of the vehicle. If you don’t confuse your brain about your movement, then travel will be more enjoyable!
Bill Yates, PhD, is a professor of otolaryngology and neuroscience and clinical and translational science at the University of Pittsburgh. He is also editor-in-chief of the Journal of Neurophysiology.