Tests · Balance
Videonystagmography: the test that investigates dizziness
Videonystagmography assesses the balance system by recording eye movements under different stimuli. Because the eyes and the labyrinth work in concert, that recording shows which part of the system is failing. It is the principal test in the investigation of dizziness and vertigo.
Medically reviewed by Prof. Aline Bittencourt, MD, PhD, CRM-MA 7562 · RQE 1832 Updated on
Why look at the eyes to investigate dizziness?
The labyrinth, in the inner ear, and the eye muscles are linked by a reflex: when the head moves, the eyes move in the opposite direction to keep the image stable. If the labyrinth on one side is working differently from the other, that reflex becomes unbalanced and nystagmus appears — an involuntary, rhythmic movement of the eyes.
Recording that movement precisely means recording, indirectly, how the labyrinth is working. That is the principle of the test.
What are the stages?
| Stage | What it assesses |
|---|---|
| Recording at rest | Whether spontaneous nystagmus is present, without stimulus |
| Eye movements | Tracking of targets and central coordination |
| Positional testing | Whether changing position triggers vertigo and nystagmus |
| Caloric test | The response of each labyrinth, stimulated separately |
The caloric test is the stage that provokes brief dizziness. It is the only way to test one labyrinth at a time, which is why it is performed.
What does the result show?
The report describes the responses at each stage and indicates whether there are signs of peripheral involvement, in the labyrinth or vestibular nerve, or central involvement, in the nervous system. It also shows whether there is asymmetry between the two sides.
Interpretation takes place at the consultation, alongside the history and physical examination. An abnormal result does not, on its own, establish the cause of dizziness; it narrows the possibilities.
Where it is carried out
At Clínica Rhinus, in the Renascença district of São Luís, as part of the neurotologic assessment, performed by the speech-language pathologists on our team and discussed at the consultation with the ENT specialist.
How should I prepare for this test?
- Bring the medical request: it is required for all tests, whether under insurance or self-pay.
- Stop medication for dizziness, sedatives and antihistamines as advised by the doctor who requested the test — never on your own initiative.
- Avoid alcohol for 24 hours beforehand.
- Have a light meal before; do not come after prolonged fasting nor straight after a heavy meal.
- Do not use make-up, sunscreen or moisturiser on the face on the day of the test: they interfere with electrode contact.
- Do not wear contact lenses on the day of the test.
- Come accompanied if possible: brief dizziness after the test is common.
Sources: Brazilian Association of Otorhinolaryngology and Cervico-Facial Surgery (ABORL-CCF) · Flint PW, Francis HW, Haughey BH, et al. Cummings Otolaryngology: Head and Neck Surgery. 7th ed. Elsevier; 2020. · Bento RF, Bittencourt AG, Voegels RL. Seminários em Otorrinolaringologia. Fundação Otorrinolaringologia.
Frequently asked questions
Questions about balance
Does the test cause dizziness?
One stage, the caloric test, stimulates the labyrinth with air or water at different temperatures and provokes brief, controlled dizziness. This is expected and is part of the test: the response to that stimulus is what provides the information. The sensation passes within a few minutes.
Do I need to stop any medication beforehand?
Frequently yes. Medication for dizziness, sedatives and some antihistamines can mask responses and compromise the test. Stopping them must be advised by the doctor who requested the test — never decided on your own, particularly with long-term medication.
How long does it take?
Between 40 and 60 minutes, covering the several stages: recording at rest, eye movements following targets, changes of position, and the caloric test.
Does the test establish the cause of dizziness?
It contributes a great deal, but not on its own. Diagnosis comes from the combination of clinical history, physical examination with manoeuvres, audiometry and videonystagmography. Some frequent causes of vertigo, such as BPPV, are identified mainly through manoeuvres performed during the consultation itself.