As part of your consultation in the neuro-otology department the doctor may ask for any combination of hearing or balance tests to help diagnose your problems.
The following sections provide a brief outline of the procedures you may have and average time taken.
Pure tone audiometry (15 minutes)
Is a hearing test to find the quietest sounds that you can hear. Different sounds are presented through headphones or a headband. You are asked to respond to the sounds by pressing a button when you hear them.
Tympanometry (5 minutes)
Whilst you are sitting still a soft tipped probe is placed in your ear canal and pressure changes show how the ear drum and middle ear are working.
Acoustic reflex threshold (10 minutes)
Short bursts of sound are presented through a soft tipped probe placed in your ear canal to check the working of the small, middle ear muscle.
Eustachian tube function test (10 minutes)
A soft tipped probe is placed in the ear canal and records the movement of the ear drum before and after swallowing a sip of water. The eustachian tube links the middle ear to the back of the throat and serves as a vent to equalise pressure between the atmosphere and the middle ear.
Oto-acoustic emission test (10 minutes)
A clicking sound is presented to your ear through a soft probe placed in the outer part of your ear. The probe then records the reflection of sound back from the inner ear .
Speech audiometry (20 minutes)
To check how well you can hear speech sounds some words will be presented to each ear in turn through headphones and you will be asked to repeat what you hear. The words are presented at medium, loud and quiet levels.
Auditory brainstem response (ABR) Test (20 minutes)
This test examines the nerve of hearing as part of the hearing pathway to the brain. Sensors are placed on the skin behind your ears, on your forehead and on the top of your head. You will then be asked to lie on a couch with your eyes closed and be as relaxed as possible. Headphones will present a loud clicking noise to one ear and a rushing sound in the other. We will be measuring time taken for the sound to get to your brain and will this be repeated for both ears.
Auditory processing tests (1-2 hours)
A variety of tests using headphones can be used to look at how the ears and brain process the sounds that you hear
- A) Dichotic digit test - two numbers are presented to each ear simultaneously and you are asked to repeat all four numbers.
- B) Frequency pattern test - you will listen to three tones of different pitch and are asked to say the pattern that you heard.
- C) Duration pattern test - you will hear three tones of long or short duration and will be asked to say the pattern that you heard.
- D) Gaps in noise - you will hear a brief rushing noise that will have some gaps/breaks in it. You are asked how many gaps you heard and this will range from 0-3 gaps.
- E) Speech in noise - you will hear some words in a noisy background and are asked to repeat the word that you hear. The noise level will vary.
These tests are designed to test the function of your balance system located in the inner ears. The brain uses the information from the balance organs together with information from your eyes. We will be looking at or recording eye movement to help us investigate your balance system.
ENG (electro-nystagmography) (20 minutes)
The tests will be carried out whilst you are sitting in a chair with sensors placed on either side of your eyes and on your forehead to record the eye movement. Some of the tests are carried out in the dark. Initially you will be asked to look at a small red light on a bar in front of you and follow it as instructed. This is followed by the chair moving gently from side to side and then turning all the way round. Next you will be asked to look ahead as a black and white striped curtain moves around you. Finally you will be asked to use your eyes to follow a red light moving from side to side in front of you.
Caloric test (25 minutes)
This important test helps determine if there is any difference between the balance function of each ear. Eye movement will be recorded either with a camera or by observing eye movement. The test is performed whilst you are lying on a couch and by irrigating the outer part of the ear with water 7C above and then 7 C below body temperature for each ear. This change in temperature changes the density of the inner ear fluid and gives you a sense of rotation/dizziness resulting in eye movement known as nystagmus. It is this nystagmus that we are looking to observe and which lasts for a couple of minutes before gradually fading away.
SVV/SVH (20 minutes)
SVV/SVH stands for subjective visual vertical / horizontal. It is a test to evaluate the function of part of your balance system in the ears. During the test, you will be sitting in a completely dark room, turning a laser light bar into vertical and horizontal positions by using a controller. You will be asked to adjust the light bar eight times to the two positions each. The results of SVV/SVH test will provide doctors certain information about your balance system.
Posturography (15 minutes)
Posturography is a balance test which measures your balance ability under different circumstances. You need to stand on a platform surrounded by a pictorial screen. The tester will inform you what is going to happen for each test condition as to whether the platform and/or the surround move(s), or instruct you to close your eyes when required. The test results demonstrate the contributions of different systems to your balance maintenance, and can show the improvement after your treatment.
Dix Hallpike manoeuvre (10 minutes)
Accumulation of crystals in parts of the inner ear can lead to positionally induced dizziness often occurring whilst turning in bed or looking up or down. The Dix Hallpike manoeuvre enables us to determine whether your dizziness is caused as a result of the above pathology. To carry out the test the doctor will lie you down quickly to stimulate the balance system, and eye movements will be observed. The particles can be then repositioned to treat the problem.
VEMP Test (Vestibular Evoked Myogenic Potential) (25 minutes)
This test is used to evaluate the function of a part of your balance apparatus. Three electrodes are attached: One on the forehead, another on the neck muscle, and the third on the collar bone. You will be asked to lie down on a couch and listen to some clicking sounds via headphones, whilst at the same time activating the neck muscle by turning or lifting your head. The electrical potential from the muscle is recorded to demonstrate the function of the balance system.