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Hearing
If you are attending the clinic for an ear-related problem, you will almost certainly require some form of hearing assessment. These are carried out to record the presence of any hearing loss and help to determine whether this is conductive or sensorineural. All the tests are performed either in the Audiology suite or in one of the Procedure Rooms.
Pure Tone Audiometry (PTA)
Speech Audiometry
Paediatric Audiometry
Loudness Discomfort Levels
Tinnitus Matching/Masking
Tympanometry
Eustachian Tube Function Test
Stapedial Reflexes
Otoacoustic Emissions (OAEs)
Auditory Brainstem Response (ABR)
Cortical Evoked Responses (CERA)
Electrocochleography
Pure Tone Audiometry (PTA)
Why?
This is a basic hearing test to determine the degree, nature and configuration of your hearing loss.
How?
You will be required to sit in a soundproof booth with headphones and will need to press a button every time you hear a bleep sound, even if it is very faint. You should ignore any rushing sounds and only react to the bleeps. This test may take up to 20 minutes depending on the results.
Speech Audiometry
Why?
This test examines speech-processing abilities throughout the auditory system and can also be used to crosscheck the validity of hearing thresholds.
How?
You will be asked to have a seat in the soundproof booth and to listen to a series of wordlists played from a CD through the headphones. Some words will be loud and others very faint. You will be instructed to repeat the word as soon as you hear it. If you only hear part of the word, you should say whatever you think you heard.
Paediatric Audiometry
t is often more difficult to obtain accurate hearing thresholds at all frequencies when testing children under 6 years of age. When testing young children, tympanometry and otoacoustic emissions are performed prior to any subjective form of testing. Then, depending on the developmental age of the child, either distraction testing, performance testing or play audiometry would be conducted to assess the child's hearing thresholds.
Loudness Discomfort Levels
Why?
Discomfort to loud sounds is a common feature of many inner ear disorders. This is an essential test for patients undergoing hearing aid assessment and fitting in order to calibrate the device appropriately. This test is used to determine the minimum loudness level of a sound that you judge to be uncomfortably loud.
How?
You will hear a series of bleep sounds getting gradually louder, and you will be asked to press a button as soon as the sound becomes uncomfortable.
Tinnitus Matching/Masking
Why?
This test is performed to assess the character of your tinnitus and its subjective loudness above threshold. A second part of the test measures the sound input required to mask out the tinnitus so that it cannot be heard. This information is useful in evaluating annoyance, disability and response to treatment.
How?
Seated in the soundproof booth, you will be instructed to listen to your tinnitus and then compare it to a sound that the audiologist presents to the opposite ear until both sounds match as closely as possible. You will be asked to first match the pitch and then the loudness. The audiologist uses the results of the matching process to create a continuous rushing or humming sound that is fed into the ear with tinnitus. You will be asked to inform them when the tinnitus has been blocked out (masked). This may be helpful for patients wishing to try a tinnitus masking device (tinnitus masker).
Tympanometry
Why?
This is a test of your middle ear function and is useful for determining whether:
- there is any fluid or congestion in your middle ear
- there is a perforation (hole) in your eardrum
- the eardrum is flaccid and weak
- there is loss of continuity of the ossicles (middle ear bones) by disease or trauma
- a grommet is blocked
- changing pressure in the ear canal causes dizziness indicating a fistula (defect) in the bone surrounding the labyrinth (balance organ)
How?
You are not required to do anything for this test other than sit very still. The audiologist will hold a soft rubber probe at the entrance of your ear canal and you may feel a slight change of pressure in your ear.
Eustachian Tube Function Test
Why?
The Eustachian tube connects the middle ear with the back of the throat and the nose and this test is to ensure that it is functioning properly.
How?
The audiologist will place a soft rubber probe at the entrance to your ear and a pressure reading will be taken. You will then be asked to 'swallow hard' a few times, and a 2nd pressure reading will be taken. Finally you will be asked to perform the Valsalva manoeuvre (by closing your nostrils and blowing air into your cheeks as if you were trying to 'pop' or unblock your ears) and a 3rd pressure reading will be taken.
Stapedial Reflexes
Why?
This test is to make sure that the stapedius muscle in your middle ear is functioning correctly and providing a protective mechanism to the hearing bones of the ear by contracting to loud sounds. This reflex is dependent on normal lower brain and facial nerve function and is therefore a helpful overall screening assessment for the auditory system.
How?
You are not required to do anything for this test other than sit very still. The audiologist will hold a soft rubber probe at the entrance of your ear canal. You will hear a series of very loud bleeps but you are not required to respond to them.
Otoacoustic Emissions (OAEs)
Why?
This is a test to measure the outer hair cell function of the cochlea (the auditory part of the inner ear). Stimulation of the normal cochlea results in the transmission of an electrical impulse along the auditory nerve through the brain to the auditory cortex where it is perceived as sound. At the same time some sound is reflected from the cochlea to the external canal and can be measured by a sophisticated recorder (cochlear echo).
How?
You are not required to do anything for this test other than sit very still. The audiologist will hold a soft rubber probe at the entrance of your ear canal and you will hear some clicking sounds but you are not required to respond to them.
Auditory Brainstem Response (ABR)
Why?
This test looks at the central hearing pathways from the cochlea along the auditory nerve all the way to the auditory cortex (the part of the brain where sounds are perceived). It is helpful in assessing possible obstruction to sound transmission due to tumours, demyelination or other problems. The central hearing pathways pass close to the central vestibular system (brain balance computer) and may be affected in neurological central balance disorders.
How?
After cleaning the skin thoroughly to remove surface oils, electrodes will be placed on your forehead and behind your ears and you will be required to sit in a dark room with your eyes closed and wearing headphones. You will hear some loud repetitive clicking noises but you are not required to respond to them as all measurements are taken automatically by a computer which records the electrical activity in the hearing pathways in the brain. This test may take up to 30 minutes depending on the results.
Cortical Evoked Responses (CERA)
Why?
This is a test that uses sound stimulation responses to objectively assess your hearing thresholds. Basic audiometry tests, such as pure tone and speech audiometry, are subjective and rely on the subject to voluntarily indicate when a sound has been heard. Objective tests use a computer to measure the electrical activity in the auditory cortex of the brain and do not therefore require a patient response. It is performed when there is any doubt over the validity of pure tone audiometry results.
How?
After cleaning the skin thoroughly to remove surface oils, electrodes will be placed on your forehead and behind your ears and you will be required to sit in a dark room with your eyes closed and wearing headphones. You will hear some loud repetitive tone bursts but you are not required to respond to them as all measurements are taken automatically by a computer which records the electrical activity in the hearing pathways in the brain. You will, however, need to stay alert while the audiologist conducts the test, which may take up to 60 minutes.
Electrocochleography
Why?
In response to sound stimulation, various parts of the auditory system produce electrical signals. This test is used to measure those signals produced by the cochlea (the inner ear) and its nerve. It can give useful information about the function or dysfunction of the cochlear hair cells and the pressure of fluid in the surrounding membrane compartments. It is most often used to determine if there is an excessive amount of fluid pressure in the endolymph, which is useful in diagnosing Méniere's disease and other allied disorders affecting inner ear fluid balance.
How?
You will have electrodes placed on your head and a tiny electrode and microphone will be inserted into the canal of the ear that is being tested. You will hear some repetitive clicking noises but you are not required to respond to them. It is very important that you try and be as relaxed as possible, since any tension can slow down the process. This test takes about 30 minutes to complete.
ENT Diagnostics
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Hearing
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