Hearing tests for deafness using audiograms and behavioural response tests

The AOAE test works on the principle that a healthy cochlea will produce a faint echo when stimulated with sound.

• A small ear-piece, containing a speaker and 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 and analysed telling 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.
• Sometimes, the results from an AOAE test are not clear. In such cases, the test may be carried out again, or an AABR test can be used.

AABR tests: sensors are placed on your child's head and neck to check the response of their nerves to sound played through headphones.

• The AABR test works by recording brain activity in response to sounds. Sound travels through the puter ear as vibrations. When it reaches the cochlea it is converted into an electical signal. This travels along the nerve of hearing to the brain where it processes into recognisable sounds.
• The AABR test does this by playing a series of clicking sound through headphones that cover the baby's ears. Three small sensors are placed on the baby's head and connected to the baby's equipment. If the hearing system is working normally then the computer will report stong responses. If there is no strong responce then the computer will report that a referral should be made.
• Around 3% of babies will go on to be referred for a full diagnostic assessment of hearing.

Positive results: Most babies show strong responses to the AOAE screening test and not require any more tests. Around 15% will be referred for further testing known as the AABR screening test. Babies who do not show strong responses to the two screenin tests will be referred on for a full diagnostic assessment of the hearing. 

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

Negative result: If the baby's ear is working normally, reaction sounds (echos) should be produced in a part of the ear known as the cochlea. If the test records strong responses from the baby's ear then they will not need any further tests.

Other tests can be carried out:

• Play audiometry tests
• Visual reinforcement audiometry
• Pure tone audiometry

• Behavioural observation audiometry (BOA)
• Visual reinforcement audiometry (VRA)
• Conditioned orientation reflex (COR)
• Conditioned play audiometry (CPA
• Conventional audiometry