This Publication Is Searchable The Merck Manual of Diagnosis and Therapy Section 20. Disorders Due To Physical Agents Chapter 282. Sea, air, car, train, and swing sickness and the space adaptation syndrome are specific forms. Etiology Excessive stimulation of the vestibular apparatus by motion is the primary cause.
Individual susceptibility varies greatly.
Afferent pathways from the labyrinth to the vomiting center in the medulla are undefined, but motion sickness occurs only when the 8th nerve and cerebellar vestibular tracts are intact. This syndrome reduces the efficiency of astronauts during the first few days of space flight, but adaptation occurs over several days. Symptoms and Signs Cyclic nausea and vomiting are characteristic. They may be preceded by yawning, hyperventilation, salivation, pallor, profuse cold sweating, and somnolence. Aerophagia, dizziness, headache, general discomfort, and fatigue may also occur.