What is videonystagmography (VNG)?
For those who struggle with their equilibrium and balance, VNG is a simple and painless diagnostic procedure that accurately determines the cause of dizziness.
The tests use a camera to track rapid eye movements in response to positional changes and visual cues. Neural pathways connect balance mechanisms of the inner ear to the eye, and quick eye movements are often a sign of a balance mechanism disorder.
The 4 parts of a VNG test
Advanced optical testing is the only way to detect these rapid eye movements. There are 4 main parts to the VNG test:
- Sensory organization testing
First, you’ll be asked to stand or walk on different surfaces, both with your eyes open and closed. This determines how well your sensory systems are working to maintain your balance.
- Ocular motor testing
Second, you’ll follow a light with your eyes. The light moves quickly in different directions, which might make you feel slightly dizzy.
- Positioning testing
Your audiologist will help you move your head up and down place your body in different positions, like sitting up or lying down. You’ll be asked to open and close your eyes, and your eyes will be recorded.
- Caloric testing
Last, you’ll lay on your back while your audiologist introduces warm, followed by cool, air into your ear canals. This extremely important step stimulates the vestibular system in each ear and compares the response between them. It determines if the vestibular organs are functioning properly, or whether one ear is drastically weaker than the other. Important instructions for VNG testingTo ensure accurate results, your audiologist will instruct you to:
- Avoid certain medications for 2 days, like sleeping pills and anti-dizziness medicine.
- Avoid alcoholic beverages for 2 days.
- No food or beverages (except for water) for 4 hours prior to testing.
- No smoking 3 hours before testing.
- No eye makeup should be worn to testing.
- Dress comfortably since you’ll be moving in different positions.