Dizziness, Vertigo And Balance Disorders
Dizziness, vertigo and balance disorders are common, particularly in older people. If you are suffering from this it is important to find out exactly what the cause is.
It could be due to a vestibular disorder (inner ear), problems with the central nervous system or high or low blood pressure.
How we test
Assessing a person’s vestibular system used to be carried out by a process called electronystagmography.
That process has been replaced by videonystagmography which is more accurate, more consistent and more comfortable for the patient. We also use another test called video head impulse.
Because successful outcomes and patient comfort is very important to Hearbase we have acquired the very latest testing equipment.
Where we test
Videonystagmography (VNG) and the video head impulse test (vHIT) are now available at The Chaucer Hospital, Canterbury if requested by a GP or, more often, by an ear, nose and throat consultant.
The VNG process is a recording system that measures continuous uncontrolled movements of the eyes – caused by a condition known as nystagmus – in response to various stimuli.
It studies the vestibular system and is based on the pupil position detected by infrared video cameras on goggles worn by the patient. It is very important to determine whether somebody’s dizziness or vertigo is due to a balance or nerve disorder.
The vHIT test incorporates a new technology that uses a high speed video goggle to measure the left or right eye velocity and record “catch up” saccades and other abnormalities. Saccades refer to the eye’s ability to quickly and accurately shift from one target to another. This is a critical skill in reading. This test is used in patients with impaired vestibular ocular reflex (VOR) function.
It is commonly used to test the function of each of the six semi-circular canals individually by measuring the VOR in response to head movements. The semi-circular canals are tiny, fluid-filled tubes in the inner ear that help you keep your balance.
The VNG test takes about 90 minutes. Goggles with infrared video cameras are placed on the patient’s head to record voluntary and involuntary eye movements. The patient focuses their eyes in a number of positions while recordings are taken.
Caloric testing is also performed. This involves air being blown down on to the ear drum. It makes the patient feel a little dizzy but this feeling is quite brief. It means that we can record the rate at which each ear reacts to the stimulation.
The vHIT is a test that should take no longer than 15 minutes and it can be used as an “on demand” clinic with ENT consultants.
There are several medications that can interfere with the results of some tests. Three days before the test takes place these should be stopped unless contraindicated by the doctor.
On the day of the test all patients should avoid drinking alcohol or caffeine. They should also avoid wearing makeup or moisturiser on their face as this might interfere with the uptake of the pupil by the video camera.
If your consultant refers you and you are medically insured your insurer will pay the cost. If you are paying yourself then you can find out more about that here.