Different types of hearing tests

Information on the tests that are used to find out the type, level and cause of deafness.

Otoacoustic Emissions (OAE) test

The test:

  • is completely painless
  • is very quick
  • gives the result immediately.

How it works

This test works on the theory that a healthy cochlea (inner ear) will produce a faint echo when stimulated with sound.

A small ear-piece, containing a speaker and a microphone, is placed in the baby’s ear. A clicking sound is played and if the cochlea is functioning properly the ear-piece will pick up the echo. This is recorded on a computer that tells the screener if the baby needs to be referred for a further screening test. If the test records strong responses from the baby’s ear then they will not need any further tests.

My baby’s test showed little or ‘no response’, what now?

It can be difficult to get a response if the baby was unsettled at the time of the test, if the room was noisy or if there is any fluid in the ear from the birth. The test is usually repeated before referral for the second type of screening test. Being referred for another test doesn’t necessarily mean that the baby has a hearing loss.

Automated Auditory Brainstem Response (AABR) test

The test:

  • is completely painless
  • takes between 5 and 30 minutes
  • gives the results immediately.

How it works

This test works by recording brain activity in response to sounds. Sound travels through the outer ear as vibrations. When it reaches the cochlea it is converted into an electrical signal. This travels along the nerve of hearing to the brain where it processed into recognisable sounds.
Headphones will be placed over the baby’s ears and a series of clicking sounds will be played through them. Three small sensors are placed on the baby’s head and connected to the computer equipment. If the hearing system is working normally then the computer will report strong responses. If there is no strong response then the computer will report that a referral for a full diagnostic assessment of hearing should be made and they will refer your baby to the local audiology department.

Further investigation

Diagnostic assessment of hearing

Babies who do not show strong responses to the two screening tests above will be referred on for this assessment. This will be done at your local audiology department or at home. One to two babies in every 1000 born will have some level of hearing loss in one or both ears.

The diagnostic assessment will include Tympanometry and Auditory Brainstem Response (ABR) testing.

Tympanometry

This is not a test for hearing, but for middle ear function. It is an objective test and is used to diagnose glue ear and other middle ear disorders. It does not require a response from the child, however they will need to sit quietly throughout the test. Usually it takes a couple of minutes to get a recording. A small probe is place inside the entrance of the ear. The probe contains a small speaker, microphone and air pump. The air pump causes the pressure in the ear canal to change and the probe measures the sound reflected back from the ear drum. Tympanometry measures how mobile the eardrum and middle ear structures are. If the eardrum is not moving freely, there is likely to be some fluid or other problem with the middle ear. The build-up of fluid is usually glue ear which can cause temporary conductive deafness. 

View our information to learn more about Glue ear.

For further information on what these tests involve you may like to read our resource Understanding Your Child's Hearing Tests.