Motion sickness is a syndrome that occurs in response to real or perceived motion, which can include gastrointestinal, central nervous system, and autonomic symptoms.
Motion sickness is considered a physiologic form of dizziness, since it is not indicative of a disease process and can be induced in nearly all normal human subjects. There is enormous variability in susceptibility to motion sickness, as it may be produced with minimal provocation in some individuals but can be very difficult to elicit in others.
The symptoms of motion sickness were first described by Hippocrates. They frequently occur during boat travel, and the principal symptom (nausea) is derived from the Greek word for ship (naus).
This topic discusses the pathogenesis, clinical presentation, treatment and prevention of motion sickness. A possibly related disorder, disembarkment syndrome, and other causes of vertigo and dizziness are discussed separately. (See "Pathophysiology, etiology, and differential diagnosis of vertigo".)
The brain receives numerous inputs that are used to estimate the motion and spatial orientation of the head. The principal sensory signals that contribute to this process are vestibular cues from the labyrinth, visual information, and somatosensory cues. Afferent information derived from the labyrinth encodes both angular motion (sensed by the semicircular canals) and linear acceleration and gravitational force (sensed by the otolith organs).