Videonystagmography (VNG) is a labyrinth examination, which is one of the most modern methods of diagnosing vertigo. VNG examination is an indispensable element of the diagnosis of vertigo and balance disorders of various etiologies, therefore patients may be referred for this examination by ENT specialists, neurologists and, in some cases, family doctors. How does videonystagmography work?

Videonystagmography (VNG)tolabyrinth examinationto explain why the patient feels dizzy. Videonystagmography consists in registering nystagmus movements with the use of a camera placed in a mask, resembling ski goggles, which the patient puts on the eyes during the examination. The eye movements recorded by the camera are transferred to a computer and then displayed as a graph on the monitor.

Videonystagmography: unpleasant symptoms

Irritation of the labyrinths during the VNG examination triggers symptoms such as:

  • dizziness
  • nystagmus
  • nausea
  • sometimes even vomiting

Therefore, it is recommended to fast before the test or only after a light meal to minimize unpleasant feelings.

Videonystagmography: caloric test

Irritation of the labyrinths in the caloric test consists in pouring water into both ears (cool and warm), therefore the contraindication to the water test is the presence of inflammation of the middle and outer ear. Therefore, the necessity to exclude inflammatory changes in the ear requires an ENT consultation immediately before the examination.

In these cases, the test may be performed using variable temperature air applicators that are equipped with some test systems.

Videonystagmography: preparation for the test

The test result may be disturbed in patients taking sedatives (sedatives, some drugs used to treat dizziness) on a permanent basis, therefore, approximately 10 days before the test, the patient is asked to discontinue these drugs. Of course, after prior consultation with the attending physician.

Videonystagmography and electronystagmography

VNG is currently the most modern method of registering eye movements. In some centers, still withthe method of electronystagmography (ENG) is successfully used, which differs from VNG only in the way of registering eye movements.

W ENG uses the phenomenon of the eyeballs generating an electric field, the changes of which, caused by eye movement, are registered by electrodes placed on both sides in the temporal area.

As in videonystagmography, the signal is sent to a computer, where it is processed into a graph and then analyzed.

The advantage of VNG over ENG is the lack of electrical artifacts, which often make it difficult to interpret the record.

With VNG it is also possible to record movements in all planes of movement and analyze "live" eye movement, the image of which is additionally displayed on the monitor screen.

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