The ability to test babies and young children has a unique set of problems, related to the child's age and ability to understand instructions on how to respond. Most children will be assessed using a combination of behavioural and physiological tests.
Behavioural Tests (Less than 7-months of age)
Behavioural tests are based on observing a change in an infant's behaviour in response to sound – such as startling to loud noises and stirring from sleep in response.
Visual reinforcement orientation audiometry (7-months to 3-years of age)
These are used to test the hearing of children between seven months and three years of age. VROA involves the child turning towards the loudspeaker when a sound is presented. By altering the frequency and intensity of the sounds, it is possible to find out about the child's ability to hear sounds across a range of frequencies.
Play audiometry (Over 3-years of age)
Shown above, this involves testing the child's hearing when headphones are worn. Play audiometry works the same way as pure tone audiometry (person indicates when they can hear a tone), except when the child hears a tone, they put a marble in a marble race, press a computer key or put a piece in a puzzle.
Physiological tests help determine which part of the auditory system is involved in the child's hearing loss. Physiological tests measure a physical response of a specific part of the auditory system and require little or no co-operation from the child.
Oto-acoustic emission testing (OAE)
Provides an idea about how hair cells in the cochlea are working. They respond to sound by producing a very soft sound of their own called an otoacoustic emission.
Brainstem evoked response audiometry (BERA)
These look at the electrical activity generated in response to sound along the Cochlea nerve to the brain. It may be carried out while a baby is in natural sleep.
Electro-cochleography (ECOCHG OR ECOG)
This is a medical test performed in hospital, under anaesthetic. It picks up the tiny electrical signals generated in the cochlea in response to sound and provides information about the functioning of the cochlea and cochlea (hearing) nerve.