Visual Nystagmography (VNG) Test
Introduction
The Ear-, Nose - & Throat (ENT) doctor have referred you to the Audiology Department at West Middlesex University Hospital for video nystagmography, a specialised balance test.
What will happen at my appointment?
The Audiologist will go through your completed questionnaire, which is attached. A pressure test will be carried out of your ears to ensure that your eardrums are normal. This is a simple test and will not cause any discomfort. If there is a problem with this test the VNG will not be carried out, and an appointment will be made for you to see the ENT doctor.
For the test, a set of goggles is placed over your eyes. These goggles have cameras in them to record your eye movements, you will also be asked to lie down on a bed, throughout the three parts of the test. It is important that you keep your eyes opened during the test. The test is carried out in darkness. The reason for this is that if you are dizzy you will focus on an item to stop the dizziness, if the room is in darkness you are not able to do this, therefore allowing the cameras to record your eye movement.
The VNG test is divided into three parts. The Doctor does not always request all three parts of the test:
EYE TRACKING: The room will be in darkness and you will be requested to follow lights on a light bar. It is important in this part of the test, that you track the moving lights, with your eyes and do not move your head.
POSITIONAL TESTING: Again, the room will be in darkness. You will be moved into various positions on the bed.
CALORIC TESTING: This part of the test takes the longest time. This is where we irrigate your ears with water, which creates a dizzy spell.
Your body is at a constant temperature of 37 degrees centigrade. We initially irrigate water into one of your ears at 44 degrees centigrade, which is 7 degrees above your body’s temperature. You may feel that the water is very warm, but it is 7 degrees centigrade above your body temperature and gives an illusion of being very warm. We irrigate your ear canal for 30 seconds. During this time you may start to feel dizzy, the dizziness will last only for a few minutes; it will give the sensation of being on a merry-go-round. Again, you will be in darkness and we will request that you keep your eyes open so that the cameras can record your eye movements. We then repeat in your other ear. We then decrease the temperature of the water to 30 degrees centigrade and repeat the procedure on both ears. You have a short rest between each irrigation, before we start the next side.
We will analyze your results and write a report to the ENT doctor. The ENT will send you a follow up appointment and the results will be discussed with you in the ENT follow up appointment.
How do I prepare for my appointment?
Do not take anti-dizziness tablets or sedatives for at least 48 hours beforehand. You must continue to take essential medications. If you are not sure about this, please contact your doctor.
Do not eat or drink tea/coffee for four hours before the test.
Do not drink alcohol for 24 hours beforehand.
It is not wise to drive a car/operate machinery immediately after the test.
Please refrain from wearing eye make-up as this can interfere with recording eye movements. If you wear glasses, please bring them along with you.
How long will my appointment take?
Approximately 90 minutes. We aim to see you on time but occasionally clinics can be unavoidably delayed. We will keep you informed of any delay to your appointment.
Can I cancel my appointment?
If you need to cancel your appointment, please call us as soon as possible. If you cancel your appointment more than two times or if you fail to attend, you will be discharged back to your GP. You will need to be referred to our service again if you want another appointment in line with the Trust Policy.