September 10, 2009

Ask the Audiologist

margaretBy Tara Hartman, AU.D, CCC-A
Audiology Consultants, P.C.

I have been feeling dizzy lately and my doctor wants me to get a VNG test.
What is a VNG test?

VNG stands for Videonystagmography. Now you know why we call it VNG! People with dizziness or balance problems may be referred by their doctor for this test. It helps to determine where the balance or dizziness problem is coming from by looking at the inner ear and central motor functions. It is one of the only tests that can isolate each ear so we can tell if it is a monaural (one ear) or binaural (both ears) vestibular problem.

During the VNG test you will be asked to wear goggles over your eyes. These goggles have special video cameras in them that record eye movement in response to stimulation of your balance system. There are several parts to the VNG test and the whole process takes about an hour and a half. During the first part of the test, you will be asked to follow a moving object with your eyes. The audiologist will be looking for inaccuracies or difficulty tracking a visual target. Abnormalities during this part of the test may indicate a central or neurological problem. During the second part of the test, the audiologist will move your head and body into different positions while looking for abnormal eye movements. This is called positional testing and it is looking for problems in your inner ear system by moving the fluid in your semicircular canals (your balance center). The last part of VNG is called Caloric testing. The audiologist will stimulate the balance system using warm and cool air in the ear canal. This test will confirm that the vestibular system of each ear is responding to stimulation.

If you ever experience any vertigo (spinning sensation), dizziness, lightheadedness, unsteadiness or balance trouble, talk to your physician and ask if a VNG test would be appropriate for you. Keep track of when the episodes occur, how long they last, and if they are associated with a particular event or movement. The more detail you can give your audiologist about your symptoms, the more helpful it is in determining the problem.