What are the different types of hearing tests?
As part of a hearing evaluation, your child's health care provider will do a complete medical history and physical exam. In addition, there are many different types of hearing tests. Some of them may be used on all ages, while others are used based on your child's age and level of understanding.
Hearing tests for the newborn
There are 2 main types of hearing screening methods for newborns. These may be used alone or together.
Evoked otoacoustic emissions (EOAE). A test that uses a tiny, flexible plug that is inserted into the baby's ear. Sounds are sent through the plug. A microphone in the plug records the otoacoustic emissions (responses) of the normal ear in reaction to the sounds. There are no emissions in a baby with hearing loss. This test is painless and is usually takes just a few minutes, while the baby sleeps.
Auditory brainstem response (ABR). A test that uses electrodes (wires) attached with adhesive to the baby's scalp. 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, further testing is needed. It is advised that all babies with hearing loss be identified by 3 months of age so that treatment can begin before the baby is 6 months old, an important time for speech and language development.
Hearing tests for the infant
Evaluation of hearing in the infant may include the use of the above EOAE and ABR tests. Also, the following may be used:
Behavioral audiometry. A screening test used in infants to observe their behavior in response to certain sounds. Additional testing may be necessary.
Hearing tests for the toddler
Evaluation of hearing may include the above mentioned tests, along with the following:
Play audiometry. A test that uses an electrical machine to transmit sounds at different volumes and pitches into your child's ears. Your child usually wears some type of earphones. This test is modified slightly in the toddler age group and made into a game. The toddler is asked to do something with a toy (i.e., touch a toy, move a toy) every time the sound is heard. This test relies on the cooperation of the child, which may not always be given.
Visual reinforcement audiometry (VRA). A test where 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 such as a toy that moves or a flashing light. The test is most often used for children between 6 months to 2 years of age.
Hearing tests for the older child
Evaluation of hearing for the child older than 3 to 4 years may include the above mentioned tests, along with the following:
Pure tone audiometry. A test that uses an electrical machine that produces sounds at different volumes and pitches in your child's ears. The child usually 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 (also called impedance audiometry). A test that can be done in most health care provider's offices to help determine how the middle ear is functioning. It does not tell if the child is hearing or not, but helps to detect any changes in pressure in the middle ear. This is a difficult test to do in younger children because the child needs to sit very still and not be crying, talking, or moving.