Glossary
Motion Sickness Glossary
21 motion sickness terms, each defined in one paragraph of plain English. It covers the medical names (kinetosis, sopite syndrome, mal de debarquement), the anatomy that causes it (vestibular system, semicircular canals, otolith organs), the treatments (dimenhydrinate, meclizine, scopolamine, acupressure) and the colloquial names people actually use (sea legs, VR legs, the dots).
Key facts
- Kinetosis is the medical name for motion sickness. Travel sickness is the British name for the same condition.
- Cybersickness is the reverse mismatch: the eyes see motion while the body stays still, which is why VR triggers it.
- Sopite syndrome is motion sickness that shows up as drowsiness, fatigue and low mood rather than nausea, so it often goes unrecognised.
- Mal de debarquement syndrome is the rocking sensation that persists for days or longer after a voyage ends. It is distinct from seasickness itself.
- The vestibular system is five sensors per side: three semicircular canals for rotation and two otolith organs for linear acceleration and gravity.
Jump to a term
- Motion Sickness
- Car Sickness
- Seasickness
- Airsickness
- Cybersickness (VR Sickness)
- Vestibular System
- Sensory Mismatch
- Semicircular Canals
- Otolith Organs
- Sound Therapy
- Dimenhydrinate (Dramamine)
- Meclizine (Bonine)
- Scopolamine
- Acupressure Wristband
- Sopite Syndrome
- Mal de Débarquement Syndrome (MdDS)
- Vestibular Migraine
- Sea Legs
- VR Legs
- Motion Cues
- Area Postrema
- Motion Sickness
- A common condition caused by a sensory mismatch between the inner ear (which detects motion) and the eyes (which may see a still view). The brain interprets the disagreement as poisoning and triggers nausea as a defense. Also called kinetosis or travel sickness.
- Car Sickness
- Motion sickness experienced specifically in cars. Most common in children aged 2-12 and backseat passengers. Often triggered by reading or phone use during travel.
- Seasickness
- Motion sickness on boats and ships, caused by rolling and pitching motion. In a large survey of passengers at sea, 21% felt slightly unwell and 7% vomited; in genuinely rough seas the rate approaches everyone aboard. Bigger ships and midship low-deck cabins produce less perceived motion.
- Airsickness
- Motion sickness on airplanes, most often during turbulence and descent. Window-seat passengers over the wing typically feel the least motion.
- Cybersickness (VR Sickness)
- Motion sickness from virtual reality. Caused by the reverse sensory mismatch: the eyes see motion but the body stays still. In a controlled study, 65.2% of participants experienced it during a 10-minute immersion and 22.8% could not finish. Most people build tolerance ("VR legs") over repeated short sessions.
- Vestibular System
- The sensory system in the inner ear that tracks motion, balance, and spatial orientation. Consists of three fluid-filled semicircular canals plus two otolith organs in each ear - five sensors total per side.
- Sensory Mismatch
- The fundamental cause of motion sickness. Occurs when the vestibular, visual, and proprioceptive systems give the brain conflicting reports about body motion. The brain pattern-matches this to ancient poisoning signals and triggers nausea.
- Semicircular Canals
- Three small fluid-filled hoops in each inner ear, oriented at right angles. They detect rotational motion of the head by sensing how fluid sloshes against hair cells.
- Otolith Organs
- Two structures in each inner ear (utricle and saccule) containing calcium-carbonate crystals that detect linear acceleration and gravity.
- Sound Therapy
- The use of precisely calibrated audio, played through ordinary headphones, as a drug-free approach to motion sickness. Because it needs no view of the horizon, it can be used with the eyes closed and after symptoms have already started. Used in apps like Dizzout.
- Dimenhydrinate (Dramamine)
- An over-the-counter antihistamine used to prevent motion sickness. Onset 30-60 minutes. Causes significant drowsiness; not recommended for drivers.
- Meclizine (Bonine)
- An over-the-counter antihistamine for motion sickness. Slower onset than Dramamine but longer duration (up to 24 hours) and less sedating.
- Scopolamine
- A prescription anticholinergic medication, typically delivered via a transdermal patch applied behind the ear. Lasts up to 72 hours. Side effects include dry mouth and blurred vision. Not recommended during pregnancy.
- Acupressure Wristband
- A band designed to press the P6 acupressure point on the inner wrist, reported by many users to reduce nausea. Sea-Bands is the most common brand. Evidence is mixed; risk profile is zero.
- Sopite Syndrome
- A subtle form of motion sickness with drowsiness, fatigue, low motivation, and mood changes instead of nausea. Often unrecognized because it lacks the classic symptoms.
- Mal de Débarquement Syndrome (MdDS)
- A rare condition where the rocking or swaying sensation persists for days, weeks, or months after disembarking from a cruise or other long voyage. Distinct from seasickness itself; tends to fade on its own but can require vestibular therapy.
- Vestibular Migraine
- A type of migraine featuring episodes of vertigo or motion sensitivity, with or without typical migraine headache. Lifetime prevalence in the general population is reported at roughly 1%. Sufferers are usually more prone to ordinary motion sickness as well.
- Sea Legs
- Colloquial term for the adaptation to ship motion that develops over hours to days at sea. Once "sea legs" set in, motion sickness usually resolves for the duration of the voyage.
- VR Legs
- Colloquial term for the tolerance to VR motion that develops over repeated short sessions. Once a user has "VR legs," cybersickness usually diminishes substantially. No trial has fixed how long it takes, and it varies widely between people.
- Motion Cues
- Visual cues that help the brain anticipate motion. Apple's iOS 18 Vehicle Motion Cues feature (launched 2024) adds animated dots to the phone screen that respond to vehicle motion, reducing the sensory mismatch when reading in a car.
- Area Postrema
- A small region in the brainstem that sits outside the blood-brain barrier and acts as a chemical and signal alarm. It is the brain area that triggers nausea in response to vestibular sensory conflict (and to actual toxins).