Vertigo
Vertigo is a medical condition where a person feels as if they or the objects around them are moving when they are not. Often it feels like a spinning or swaying movement. This may be associated with nausea, vomiting, sweating, or difficulties walking. It is typically worsened when the head is moved. Vertigo is the most common type of dizziness.
The most common diseases that result in vertigo are benign paroxysmal positional vertigo (BPPV), Ménière’s disease, and labyrinthitis. Less common causes include stroke, brain tumors, brain injury, multiple sclerosis, and migraines. Physiologic vertigo may occur following being exposed to motion for a prolonged period such as when on a ship or simply following spinning with the eyes closed. Other causes may include toxin exposures such as to carbon monoxide, alcohol, or aspirin. Vertigo is a problem in a part of the vestibular system. Other causes of dizziness include presyncope, disequilibrium, and non-specific dizziness.
Motion sickness
Motion sickness is one of the most prominent symptoms of vertigo and develops most often in persons with inner ear problems. The feeling of dizziness and lightheadedness is often accompanied by nystagmus (an involuntary movement of the eye characterized by a smooth pursuit eye movement followed by a rapid saccade in the opposite direction of the smooth pursuit eye movement). During a single episode of vertigo, this action will occur repeatedly. Symptoms can fade while sitting still with the eyes closed.
Virtual reality sickness
Virtual reality sickness occurs when exposure to a virtual environment causes symptoms that are similar to motion sickness symptoms. The most common symptoms are general discomfort, headache, stomach awareness, nausea, vomiting, pallor, sweating, fatigue, drowsiness, disorientation, and apathy. Other symptoms include postural instability and retching. Virtual reality sickness is different from motion sickness in that it can be caused by the visually-induced perception of self-motion; real self-motion is not needed. It is also different from simulator sickness; non-virtual reality simulator sickness tends to be characterized by oculomotor disturbances, whereas virtual reality sickness tends to be characterized by disorientation.