What is a VNG?
Videonystagmography (VNG) is designed to test inner ear and central motor functions. Think of it as an MRI for your balance system. VNG testing is considered the new gold standard for testing inner ear functions over Electronystagmography (ENG), this is due to the fact that a VNG measures the movements of the eyes directly through infrared cameras, instead of measuring the mastoid muscles around the eyes with electrodes like the previous ENG version. By recording and measuring eye movements, the VNG can assess the function of your inner ear, brain, and balance system to determine the cause of your symptoms. The test takes between 30-60 minutes total. VNG testing is considered to be more accurate, consistent, and comfortable for the patient. Due to these facts, a superior test is more easily achieved.
When is a VNG used?
VNG testing is used to determine if a vestibular (inner ear) disease may be causing a balance or dizziness problem. A VNG test is one of the only tests available today that can decipher between a unilateral (one ear) and bilateral (both ears) vestibular loss. VNG testing is a series of tests designed to document a person’s ability to follow visual objects with their eyes and how well the eyes respond to information from the vestibular system.
This test also addresses the functionality of each ear and if a vestibular deficit may be the cause of a dizziness or balance problem. To monitor the movements of the eyes, infrared goggles are placed around the eyes to record eye movements during testing. VNG testing is non-invasive, and only minor discomfort is felt by the patients during testing as a result of wearing goggles. Appointments usually last about 1.5 hours, and testing is covered by all insurances.
What Does a VNG Test Entail?
A VNG test consists of four parts. These parts include:
1. Occular Mobility
You will be asked to have your eyes follow objects that jump from place to place, stand still, or move smoothly. The technician will be looking for any slowness or inaccuracies in your ability to follow visual targets. This may indicate a central or neurological problem, or possibly a problem in the pathway connecting the vestibular system to the brain.
2. Optokinetic Nystagmus
You will be asked to view a large, continuously moving visual image to see if your eyes can appropriately track these movements. Like the occular mobility tests, the technician will be looking for any slowness or inaccuracies in your ability to follow visual targets. This may indicate a central or neurological problem, or possibly a problem in the pathway connecting the vestibular system to the brain.
3. Positional Nystagmus
The technician will move your head and body into various positions to make sure that there are no inappropriate eye movements (nystagmus), when your head is in different positions. This test is looking at your inner ear system and the condition of the endolymph fluid in your semi-circular canals. The technician is verifying that small calcium carbonate particles called otoconia are not suspended in the fluid and causing a disturbance to the flow of the fluid.
4. Caloric Testing
The technician will stimulate both of your inner ears (one at a time) with warm and then cold air. They will be monitoring the movements of your eyes using goggles to make sure that both of your ears can sense this stimulation. This test will confirm that your vestibular system for each ear is working and responding to stimulation. This test is the only test available that can decipher between both unilateral and bilateral hearing loss.
What do I need to do to get ready for the VNG?
Make sure your ears are clean.
Please have your physician check to make sure your ears are clear and free of wax prior to your appointment. Why? Because this test requires that your ear canals are free of wax and that your eardrums are intact.
You may have to stop taking some of your medications.
These instructions are very important…you may have to read the next section again. Certain medications may interfere with the test results. It is important that you read and comply with these instructions. DO NOT STOP TAKING MEDICATIONS FOR HIGH BLOOD PRESSURE, SEIZURES, DIABETES, OR OTHER DISORDERS.
- 2 days prior to your appointment: Discontinue all medications for dizziness (Antivert, meclizine, Dramamine Scopolamine, valium) If unsure, consult your physician.
- 24 hours prior to your appointment: Alcohol or caffeine must be discontinued(including wine, beer, & cough medicines containing alcohol).
And, it is necessary that you DISCONTINUE the following medications:
- Anti-nausea medicine (Dramamine, Bonine, Marezine, Phenergan, Thorazine)
- Antivertigo medicines (Antivert, meclizine, Dramamine Scopolamine, etc)
- Narcotics or Barbituates (Codeine, Demerol, Percodan, Hydrocodone, Vicodin)
- Antihistamines or any over-the-counter cold remedies.
On the day of your appointment
- Do not wear make-up or apply oils or lotions to your face the day of the evaluation. This is important for assessing eye movements correctly.
- Wear comfortable clothing.
- Do wear your eye glasses. Comfortable contacts may be worn, but are not recommended if you have dry eyes or irritation.
- Bring someone with you to drive you home. Rarely, some people may continue to feel a little dizzy after the testing. Most people, however, feel fine after a few minutes.
- Arrive on time or reschedule your appointment if necessary. Because this test takes about an 1 hour, a late or absent person greatly affects our schedule.
- Do not have any food or beverages for four (4) hours before the test. You will not be put to sleep, but you will be more comfortable during the test with an empty stomach.
Please call us if you have any questions, 941-957-8288.
What do I need to bring?
Photo ID and insurance card(s), names of all of your medications, and any paperwork we asked you to complete in advance.