VNG = Videonystagmography
VNG testing is used to determine if a vestibular (inner ear) disease may be causing a balance or dizziness problem, and 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 may be felt by some patients during testing as a result of wearing the infrared goggles. Appointments usually last about 1.5 hours, and testing is covered by all insurances.
There are 4 Parts to the Test
1. Occular Mobility
The patient is asked to have their eyes follow objects that move around in various patterns. The technician will be looking for any slowness or inaccuracies in their 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
The patient is asked to view a large, continuously moving image to see if their eyes can appropriately track these movements. The technician will again be looking for any slowness or inaccuracies in their 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 the patient’s 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 assesses the inner ear system and the condition of the endolymph fluid in the semi-circular canals. The technician is verifying that small calcium carbonate particles called otoconia are not suspended in the fluid, causing a disturbance in the flow of the fluid.
4. Caloric Testing
The technician will stimulate both of the patient’s inner ears (one at a time) with warm and then cold air. They will be monitoring the movements of the patient’s eyes using goggles to make sure that both of their ears can sense this stimulation. This test assesses the functional stimulation response of the vestibular balance system in each ear. This test is the only test available that can decipher between a unilateral and bilateral loss.