What are ENG and VNG Testing?
Electronystagmography (ENG) literally means electrical recording of nystagmus – a specific type of eye movement. Videonystagmograpy (VNG) is a similar test with the added enhancement of video recordings. ENG/VNG is a series of tests to assist in diagnosing patients who have dizziness or other balance problems.
Our eyes and ears depend on each other for good balance and clear vision. Head movement and other stimulation of the inner ear sends signals to the muscles of the eyes via the nervous system, called the VOR (vestibulo-ocular reflex). The VOR ensures the eye movements necessary to maintain clear vision as the head moves. Throughout a series tests, the examiner stimulates the inner ears in controlled ways and measures the involuntary eye movements that result.
What happens during an ENG/VNG test?
During a VNG test, eye movements are recorded by an infrared video camera. The patient wears goggles with a lens that is connected to the computer for recording the data. One test evaluates the movement of the eyes as they follow a moving target. Another observes eye movements as the head is positioned in different directions. During the caloric test, warm or cold air is circulated in the ear canal. The temperature change stimulates the inner ear in order to test the eye-movement (nystagmus) response. The examiner may ask the patient to perform some mental tasks during the test, such as counting backward or thinking of names. These activities keep the mind busy and alert so that valid test results are obtained. The Minneapolis Clinic of Neurology performs an audiometry (hearing) test along with the VNG test.
Total testing time is usually 1 hour to 1-½ hours. Most patients feel about the same afterward; however, we recommend that you have a relative or friend along to drive you home, as a small percentage of patients will feel increased symptoms after the test.
How should I prepare for an ENG/VNG test?
You will be given specific instructions when you schedule the test. You may need to refrain from certain medications for 48 hours prior to the test, so please read the instructions carefully. Again, we recommend that you bring a relative or friend along who can drive you home, as a small percentage of patients will feel increased symptoms after the test.
Minneapolis Clinic of Neurology - Golden Valley/Main Office
4225 Golden Valley Road
Golden Valley, MN 55422
Minneapolis Clinic of Neurology - Burnsville Office
Oak Ridge East Professional Building
675 East Nicollet Boulevard, Suite 100
Burnsville, MN 55337