Vertigo, dizziness, and balance problems can be life altering. For many people it can affect their ability to do even the simplest daily tasks. If you are experiencing vertigo or balance issues, your doctor may want to refer you for a VNG balance evaluation, VEMP, and/or ECOG test. Audiologic testing may also be recommended to help differentiate certain ear conditions.
What is a VNG Balance Evaluation?
VNG stands for videonystagmography, which is a series of tests that evaluate the health of your inner ear and your central motor function. VNG testing can possibly uncover the root cause of your vertigo, dizziness or balance issues, and allow your physician or audiologist to treat it appropriately and effectively.
What Tests Will Be Performed?
VNG testing consists of a variety of tests to uncover the root cause of your symptoms. Prior to the testing, a medical and dizziness history will be discussed that can help lead to a diagnosis. The sense of balance will then be qualitatively measured using a combination of tests of balance. Some basic screenings will also be performed to help with differential diagnosis. The VNG evaluation consists of several tests:
Gaze and Ocularmotor Testing
This testing checks for your ability to follow visual targets. You will attempt to follow targets with your eyes while an object is jumping, moving slowly, or standing still. Inability to track objects properly could indicate central or neurological problems or possibly an issue with the vestibular system connecting to the brain.
Positional Nystagmus
This test will help to give an idea of the health of your inner ear system. You will be asked to move your head and body into different positions, checking for inappropriate eye movements in each position.
Caloric Testing
This test can determine if you have vestibular weakness in one or both ears by checking to see if your ears can detect sensations properly. Your eyes will be monitored while your inner ears are stimulated (one at a time) with warm or cool air.
Preparing for VNG Testing
Because of the nature of the tests, there are some preparations you will need to make before your evaluation. Our staff will provide you with clear instructions on how to prepare for your examination. For example, we may ask you to discontinue certain medications and not to consume any alcoholic beverages at least 48 hours before the tests. If you have any questions about your instructions or how to prepare for the test, please ask us.
The entire VNG evaluation typically lasts between 60 to 90 minutes and can cause some dizziness. This dizziness usually subsides within a short period of time. It is advised that you bring someone with you who can drive you home afterward if you are unable to drive or do not feel well after the tests.
VEMP Testing
VEMP stands for vestibular-evoked myogenic potential testing. This test provides information regarding portions of the inner ear that is not provided in the VNG test. For patients, the procedure of this test is very similar to the ABR test such that sounds are presented in each ear while electrodes placed on the head and neck measure the reflex potentials from these sounds. The VEMP not only can provide information about the inner ear balance system, it has traditionally provided information on certain neurologic conditions.
ECOG Testing
ECOG, or ECochG, stands for Electrocochleography testing. This is another test that measures electrical activity in the inner ear in response to a sound. For patients, the procedure of this test is also very similar to the ABR test such that sounds are presented in each ear while electrodes placed on the head and in the ear measure the reflex potentials from these sounds. Just like the VEMP or ABR, no responses are required from the patient. Actually, the patient can even sleep during the test session. The responses recorded from the ECOG test may help aid in the diagnosis of certain inner ear disorders associated with dizziness or vertigo.