What are hearing tests?

Hearing tests are conducted to ascertain whether hearing is normal or not and if there is a problem with hearing where that problem lies anatomically. This combined with physical examination enables Ear Nose and Throat Surgeons to formulate strategies to restore hearing to normal or near normal.

Why do I need a hearing test?

Essentially hearing tests are done for two main reasons. One is to diagnose the cause of hearing loss and secondly in those patients with documented hearing loss to help in the fitting of appropriate amplification devices such as hearing aids.

Where can I take a hearing test?

Hearing tests are conducted in acoustically insulated testing booths which are calibrated to an international standard using audiometers (hearing testing devices) which are also calibrated to international standards. Hearing tests that are not done in a hearing booth are by and large less reliable than those done in optimal circumstances.

Testing protocols have been established to ensure a standardised set of guidelines to enable optimal test, re-test reliability and to facilitate hearing tests being compared from clinic to clinic, from state to state or even from country to country.

Who can perform hearing tests?

In Australia there is no standardised law specifying qualifications for the performance of a hearing test. Therefore it is important that you know the qualifications of the person performing your hearing test. They tend to fall into several categories:

Audiologist

An Audiologist is a person who has had at least 4 years of University training with the current qualification in New South Wales being a postgraduate Masters degree in audiology. Members of the Audiological Society of Australia have their qualifications checked and verified by that Society and undertake continuing professional development to maintain a current clinical certificate. This ensures that they are of the highest caliber of training and they are up to date with the latest in terms of audiological developments.

Audiometrist

An audiometrist is someone who has undertaken a 6 month TAFE course in basic hearing testing and the simplest of hearing aid fittings. They have less formal training and nearly always much less by way of practical experience than audiologists. They are by and large capable of doing simple screening testing and fulfill the minimum requirements for the fitting of hearing aids in the adult population. For more complex adult problems and for the testing or fitting of hearing aids in children an audiologist qualification is essential.

Nurse audiometrists

Nurse audiometrists usually have a degree in nursing and rudimentary training in screening audiometry. They are essentially used for the screening of children’s hearing in child care centres and in the community health setting. Nurse audiometrists usually work under the supervision of an audiologist, or an otolaryngologist be that in a private practice or in the public health setting.

Tip: "it is important that you know the qualifications of the person performing your hearing test."

A specialist sub-group of audiologists are those involved in the SWISH (State-Wide Infant Screening – Hearing) programme. These audiologists have specific training to undertake the testing of every newborn in New South Wales. There is a state wide programme to test the hearing of all newly born babies to ensure that their hearing is normal or near normal to facilitate the development of normal speech and language. In the first 6 months of life our hearing system develops remarkably quickly with specific parts of the brain developing to allow the “switching on” of brain activity specific for language development. Hearing loss during this time of life can have profound effects on the development of speech and language.

When to get a hearing test?

Hearing assessment, under medical supervision preferably, should be undertaken whenever a change in hearing is noticed, this could be in one or both ears. It may involve a sensation of fullness or blockage in the ear, a deterioration in the clarity of the spoken word, differential hearing in one ear compared to the other or the development of noises in the ear (tinnitus). If these changes are sudden it is important to get urgent assessment and hearing test conducted because some of the causes of damage to the inner ear have to be seen within the first 72 hours for them to be reversible.

How do we perform a hearing test?

Hearing tests vary according to the age of the individual to be tested, the capacity of the individual to cooperate with testing procedure and the reason for the test being done.

A basic adult hearing test comprises three components, an audiogram, this is a measurement of the threshold of hearing, that is to say the softest level of sound audible across a range of pitch, presented to the right and left ear independently. Secondly, speech discrimination which is a test to detect the ability of the ear to unravel sounds which sound similar such as hat, cat, bat and rat and thirdly tympanometry which is a measure of middle ear pressure and compliance. These three tests, together with clinical examination, create a picture as to how the outer, middle and inner ear are functioning.

Hearing test for Children

For young children (3-5 year olds) a modified version of the audiogram is performed, something called play audiometry where threshold levels (or near threshold levels) can be reliably established by creating a game out of the test. The child is instructed to place a block in a stack or something similar each time they hear a sound. For most children of this age group a reliable audiogram including masking can be undertaken.

For children under the age of 3 a behavioural screening test is used –VROA (visual reinforcement operant audiometry). This is usually undertaken by two test audiologists and involves the child playing quietly in a room with a speaker. A sound is presented through the speaker (loud enough to be easily heard) and when the child turns to the sound a reward (usually a friendly puppet) is seen. This is repeated until the child learns to associate the sound with the reward and then the volume of the sound is reduced to establish hearing thresholds.

Hearing test for Babies

For babies and for people not able to undertake the behavioural testing described above, technology has allowed for electrophysiological measures of hearing to be undertaken. The SWISH programme, already mentioned, uses an Auditory Brainstem Evoked response protocol which records electrical activity from the brainstem in response to sounds of varying frequency introduced into the ear. Similarly Cortical Evoked Potentials can be recorded from adults unwilling or unable to undertake behavioural audiometry as described above.