What is a VNG test? Do you need one?

If you have been experiencing bouts of dizziness, a loss of balance or a sensation of spinning, then your doctor may recommend you have a Videonystagmography. But do you know what it is, what it looks for, and what to expect from the test?

Videonystagmography (VNG) measures a particular type of involuntary eye movement known as nystagmus. These eye movements may be fast, slow or jerky. Your eyes may move up or down, side to side or both. This can occur if your brain gets contradictory messages from both your eyes and your balance system in the inner ear. This is what may be causing you to feel dizzy.

Nystagmus can briefly occur when you move your head a particularly way or look at certain patterns. If it happens when you don’t actually move your head or if it lasts for a long period, however, then it may mean you have a vestibular system disorder. Your vestibular system is your body’s main center of balance and works with your brain and eyes. Your brain communicates with these different systems to control your balance. A VNG is used to determine if you have disorder in the vestibular system or in the part of your brain that controls balance.

If you have symptoms of a vestibular disorder then you may need a VNG. While the main symptom is dizziness, you may also feel light-headed as if you may faint and that you or the world around you is spinning, known as vertigo. Other symptoms include:

• Involuntary eye movements
• Tinnitus or ringing in the ears
• A feeling of pressure or fullness in the ear

During your VNG test, you will be asked to sit in a dark room wearing special goggles. These goggles have a camera that records your eye movements. There are three main parts of a VNG:

1. Ocular testing. A light will move rapidly in different directions. You will be asked to follow it with your eyes.
2. Positional testing. You will move your head and body in different positions and directions. As you do so you will alternate these actions with your eyes open and closed.
3. Caloric testing. You will be asked to lay on your back as your doctor inserts warm and cool air or water into your ear canal. This stimulates the vestibular response in each ear.

Be prepared that the test may make you feel dizzy for a short period, so it's essential you don't drive home afterwards, in case you feel dizziness for a longer period.

The results of your VNG will determine whether your dizzy symptoms are as a result of an abnormality in your inner ear. Your doctor will then be able to make a conclusive diagnosis and suggest appropriate treatment options for you. This may include:

• Meniere's disease, which can cause dizzy spells, hearing loss and ringing in the ears (tinnitus). While there’s no cure for it, your doctor may recommend medication or changes in your diet to manage it
• Labyrinthitis, which causes acute vertigo and significant hearing loss. It is an otologic emergency and must be treated within 72 hours
• A condition that affects the part of the brain that helps you to control balance.

If your balance problems continue or you are concerned about your hearing, it’s a good idea to book an appointment with a licensed hearing care specialist who will be able to evaluate your hearing and determine if you have any additional issues that the VNG didn’t pick up.

While a VNG may sound daunting, if you are experiencing symptoms of dizziness, it’s one of the best ways to determine the cause of your dizziness and help your doctor to identify the best course of treatment for you.