As part of a hearing evaluation, your child's doctor will do a complete health history and exam. In addition, there are many different types of hearing tests. Some of them may be used on children of all ages. Others are used based on your child's age and level of understanding.

There are two main types of hearing screening methods for newborns. These may be used alone or together:

• Evoked otoacoustic emissions (EOAE). This test uses a tiny, flexible plug that is put into the baby's ear. Soft clicking sounds are sent through the plug. A microphone in the plug records the otoacoustic responses (emissions) of the normal ear in reaction to the sounds. There are no emissions in a baby with hearing loss. This test is painless and often takes just a few minutes. It's done while the baby sleeps.
• Auditory brainstem response (ABR). This test uses wires (electrodes) attached with adhesive to the baby's forehead and behind each ear. While the baby sleeps, clicking sounds are made through tiny earphones in the baby's ears. The test measures the brain's activity in response to the sounds. As in EOAE, this test is painless and takes only a few minutes.

If the screening tests finds that your child has a hearing loss, more testing is needed. Babies with hearing loss should be identified by age 3 months. Then treatment can begin before the baby is 6 months old, an important time for speech and language development.

A baby's hearing evaluation may include the EOAE and ABR tests described above. This test may also be used:

• Behavioral audiometry. This is a screening test used in babies to watch their behavior in response to certain sounds. More testing may be needed.

A toddler's hearing assessment may include the tests mentioned above, along with these:

• Play audiometry. This test uses an electrical machine to send sounds at different volumes and pitches into your child's ears. The child often wears some type of earphones. This test is changed slightly in the toddler age group and made into a game. The toddler is asked to do something with a toy (such as touch or move a toy) every time the sound is heard. This test relies on the child's cooperation, which may not always be possible.
• Visual reinforcement audiometry. For this test, the child is trained to look toward a sound source. When the child gives a correct response, the child is rewarded through a visual reinforcement. This may be a toy that moves or a flashing light. The test is most often used for children 6 months to 2 years old.

A hearing evaluation for a child older than age 3 to 4 may include the tests mentioned above, along with these:

• Pure tone audiometry. This test uses an electrical machine that makes sounds at different volumes and pitches in your child's ears. The child often wears some type of earphones. In this age group, the child is simply asked to respond in some way when the tone is heard in the earphone.
• Tympanometry (impedance audiometry). This test can be done in most doctors' offices to help find out how the middle ear is working. It does not tell if the child is hearing or not. But it helps to find any changes in pressure in the middle ear. This is a hard test to do in younger children because the child needs to sit very still and not be crying, talking, or moving.