A videonystagmography, or VNG, is a procedure to evaluate dizziness and more accurately determine if the inner ear is causing it. This procedure typically requires a referral by an ear, nose and throat specialist (i.e., ENT, otolaryngologist) such as our Anchorage physicians, or a neurologist or physical therapist. You’ll also need to have a hearing evaluation prior to the procedure.
During the procedure, the patient will wear a pair of virtual reality-like goggles with cameras to measure eye movements. These eye movements are called nystagmus, and they are related to the inner ear. The results also provide specificity of which ear is causing the dizziness, as well as whether it is peripherally (i.e., at ear level) or centrally located (i.e,. in the brain).
The procedure itself is a series of four tests, lasting about 90 minutes. The first test evaluates rapid eye movements, called saccades. Then the patient follows a target that moves smoothly and is tracked with the eyes. The third part is a positional test. In this part of the evaluation, the patient’s head is placed in various positions to monitor for nystagmus. Finally, calorics are evaluated. Calorics measures the ear’s responses to cool and warm temperatures administered by air or water.
Unlike most evaluations for Alaska patients in audiology, the VNG evaluation does require preparations prior to the test day. The most important preparation is to avoid certain medications, both prescription and over-the-counter. Meclizine or any medications to help subside the dizziness cannot be taken 48 hours prior to the evaluation. In addition, avoiding caffeine and nicotine products is required. It is always recommended that the patient brings someone to drive home following the procedure.
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