How is Hearing Tested in children?
A newborn having their hearing tested under the universal neonatal hearing screening program.
Newborn Infant Hearing Screening
All States and Territories in Australia have universal neonatal hearing screening programs. These programs screen the hearing of all newborn babies in their first few weeks of life. They aim to find out as early as possible whether a baby has a hearing loss. The screen is performed by trained hearing screeners using valid and reliable technology and is usually carried out at the baby's bedside in hospital while they are asleep.
Auditory Brainstem Response (ABR)
The ABR is the most common test given to babies during the screen. Sensors are placed on the baby’s forehead and behind the ears with some sticky gel (see image above). Clicking sounds are then played through an earpiece placed inside the baby’s ear while they are asleep. Brain responses to these sounds are recorded. These brain responses provide information about the softest level of sound the baby can hear. This information can help confirm whether further testing or further interventions (such as hearing aids) or special education may be recommended.
Audiogram
For older children, behavioural tests are used to determine a child's response to sound. Each ear is tested separately with the ear not being tested covered with a soundproof earpiece. A series of sounds are produced by a machine and relayed to the ear being tested. The sounds vary according to their pitch or frequency (cycles/second) and loudness (decibel level). The loudness of the sound detected by the child is recorded for several frequency levels between 250 and 8000 cycles per second (see below images).
The degrees of hearing loss.
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An audiogram of someone with Usher syndrome Type 1, showing a profound hearing loss in both the left (X) and right (O) ears.
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