Vertigo & Balance Test
Acute vertigo is a disabling and treatable symptom arising from disorders affecting the inner ear balance organs and their connections with the central nervous system. Our objective is to offer a rapid assessment service for patients with acute vertigo and chronic imbalance.
Vertigo is a hallucination of movement that is caused by a left-right difference between the inner ear balance organs or their connections. “Vertigo” is not a diagnosis. It is only a term used to describe dizziness associated with a sensation of self motion or movement of the environment. Vertigo is merely a symptom just like “headache” or “chest pain”.
There are many different causes of vertigo. It is not always easy to describe the sensation experienced, which might be a spinning, rocking, tilting or dropping sensation. Sometimes it can be difficult to separate vertigo from sensations like lightheadedness, disorientation or brain fog. Sometimes, the cause of vertigo is evident in the history of its presentation alone. The physical examination and vestibular testing can also help determine the cause of vertigo. Examination during an attack of vertigo also provides valuable information, therefore our clinic focuses on seeing our patients as close as possible to an attack.
Vestibular Function Testing
Each inner ear balance organ has five end organs: the three semicircular canals (anterior, posterior and horizontal canals) which sense rotation or “angular acceleration” and two gravity sensors (utricle and saccule) that sense “linear acceleration” including gravity. It is now possible to test all five end organs. Here are some tests we commonly use in clinic.
Video Head Impulse Test (VHIT)
Our inner ear balance organs stabilise the visible world upon the retina as we move our heads during walking and running. This is achieved by the vestibulocular reflex, by means of powerful connections between the balance organs and the extraocular muscles which move the eye. The VHIT tests your ability to match rapid head movements with equal and opposite eye movements.
You will be asked to sit upright and wear a pair of lightweight video-glasses. You will focus upon a fixed target. The examiner (an audiologist or doctor) will deliver 20 head turns in the direction of each semicircular canal. The speed of eye movement is measured and expressed as a fraction of the speed of head movement. This test is a valuable screening test of semicircular canal function.
Do not wear mascara or eye-liner since these interfere with pupil tracking.
Time taken: 10 minutes
Vestibular Evoked Myogenic Potentials (VEMP)
The gravity sensors of our inner ear balance organs have retained their primitive ability to be activated by sound and vibration. The VEMP test exploits this sound and vibration sensitivity to assess the integrity of our gravity sensors.
Surface electrodes (like ECG dots) will be applied to the skin directly underlying your lower eyelids and over your neck muscles. You may be asked to look upwards or to elevate your head 45 degrees above horizontal. You will be asked to listen to clicking noises through headphones. Alternately, vibration pulses will be delivered over your forehead at 3 pulses per second. The recordings taken from your neck muscles or eye muscles give us useful information about your gravity sensors.
Time taken: 10 minutes
The Bithermal Caloric Test
While lying semi recumbent on a bed, dark goggles will be placed on your eyes and a small infrared camera records your eye movements. The test involves irrigating the external ear canal with warm and cool water for 40 seconds; you will experience a sensation of tilting or turning as your balance
organs are stimulated by the water. You may also notice your eyes flicking in response to the stimulus (nystagmus). The velocity of these eye movements is recorded and compared for left and right ear stimulation. It is important to keep your eyes open and to remain alert during the test. The nurses who perform the test are highly skilled and will ensure that you feel safe and comfortable during the test. They may also engage you in conversation to ensure you stay awake.
You will need see your general practitioner one week before the test to ensure there is no wax in your ears, and you must not eat or drink for 4 hours before the test. Diabetic patients could request an early morning (8.30 AM) appointment, take their regular hypoglycaemic tablets before the test and ensure they have breakfast when the test is completed. Patients on Insulin should delay the morning insulin dose until just before breakfast. If you are given a later appointment, you could eat an early (~5AM) breakfast and take your insulin/tablets before breakfast. Medications specifically taken to quell an attack of vertigo such as prochlorperazine (“stemetil”) or Cinnarizine (“stugeron”) should be withheld for 48 hours before the test. If you are a long term user of sedatives, please speak to your doctor to check if these can be withdrawn. All other medications including migraine prevention drugs, pain killers and cardiac medications should be taken with a sip of water, on-time as prescribed.
Time taken: 30-60 minutes
Auditory Brainstem Response (ABR)
This is an extension of the standard hearing test, and further measures the auditory nerve from the ear (cochlea organ) to the brain. It is a relatively simple and non-invasive test.
The audiologist will first cleanse the skin on the forehead and ears and will place very small recordings cups onto the head and earlobes with gel. Then the patient lies comfortably on a bed with their eyes closed, in a darkened room, as clicking sounds are played for about 5 minutes into each ear separately. The recording cups measure brain activity which help to determine how the brain is hearing and processing the sounds, and so there is no response needed from the patient.
Time taken: Approximately 30 minutes
Bias Testing (Subjective Visual Horizontal Test)
This test measures a person’s ability to determine what is ‘level’, and is a test of our gravity-sensing balance organs (the otolith organs) and how they work with our eyes.
In this test, the patient sits in a darkened room where a small bar of light sits in front of them. The light bar is then tilted to different degrees off-centre, and the patient must use a handheld remote control to tilt the bar of light back to what they feel is perfectly flat to the horizon. The test is repeated 10 times for each eye separately.
Time taken: Approximately 10 minutes
Audiometry (Hearing Test)
Your hearing threshold provides valuable clues to the origins of vertigo. A hearing test is therefore an essential component of balance testing. Screening audiometry takes only 20 minutes. Audiometry with impedance and speech testing takes 40 minutes.
Your ears will need to be clear of wax
Time taken: 20 minutes for screening
Time taken: 40 minutes with impedance and speech testing
This test measures the distortion of inner ear membranes (linings) caused by the presence of excess inner ear fluid. It is useful in the diagnosis of Meniere’s Disease and related disorders.
The test is performed by placing a ball (electrode)e placing on the ear drum. During the test, noises (clicks or tones of specific frequencies) are presented through headphones.