When Should an Infant Be Screened for Hearing Loss?

• All infants should be screened for hearing loss before 1 month of age, preferably before leaving the birth hospital. The age of a child when a hearing loss is diagnosed is important to the development of the child’s speech, language, cognitive and psychosocial abilities.



• Without universal screening by 1 month of age, the average age at which hearing loss is identified in children is 2 to 3 years old.
  
  
• Newborn hearing screening costs about $30 per child and takes about nine minutes to do. Costs are much higher if a hearing loss is not diagnosed until later in life. In the 1995-1996 school year, the total U.S. costs for special education programs for children with hearing loss exceeded $375 million.



• Infants with risk indicators for progressive or delayed-onset hearing loss should receive audiologic monitoring every six months until age 3 years. (JCIH Year 2000 Position Statement) Note: This statement is available from the American Academy of Pediatrics Web site at www.aap.org.
  
  
• Find out what screening guidelines are recommended by various organizations.

What Happens If an Infant Does Not Pass the Hearing Screening?

• All infants who do not pass the hearing screening should be referred for further testing to rule out or confirm a hearing loss.



• All infants with confirmed hearing loss should be referred for a comprehensive medical evaluation to assess the causes and look for potential or related disabilities.



• Depending on the results of the audiological and medical examinations, infants may be referred to an intervention program.
  
  
• To find out more about intervention options, please contact CDC Info at 1-800-232-4636 or cdcinfo@cdc.gov.
  
  
• To learn more about infant hearing loss and how the ear works you can visit the Boys Town National Research Hospital at babyhearing.org.

How Can I Find Resources Such as Hearing Screening Tests That Are Available in My Area?

To learn more about programs and services in your area, please contact your local Early Hearing Detection Intervention (EHDI) Program coordinator. You will find this information at www.cdc.gov/ncbddd/ehdi/documents/stateHL_contacts.pdf.

What Does It Mean to Have a False Positive Newborn Hearing Screening Test?

A false positive hearing screening test result is when a baby does not have a hearing loss but the newborn does not pass the hearing screening. Hearing screening tests are not meant to diagnose hearing loss in infants. Instead, they are meant to find all infants that might have a hearing loss. Because they are not a diagnostic test, hearing screening tests sometimes misidentify infants as having a hearing loss.

If a baby does not pass the newborn hearing screening test, it is VERY important to make sure the baby gets follow-up testing to be SURE that the baby does not have a hearing loss.

In the United States, between 10 and100 babies per 1,000 (1 percent to 10 percent) do not pass the screening test. Only one to three babies per 1,000 (less than 1 percent) actually have hearing loss. This means that most of the babies referred for diagnostic testing will be shown to have no hearing loss.

Why Don’t All Infants Have a Diagnostic Test for Hearing Loss?

A diagnostic test takes a long time, it cannot be done before a baby goes home from the birth hospital, and it is expensive. A hearing screening test is quick, it can be done before a baby leaves the birth hospital, and it is relatively inexpensive.

Screening tests are common in medicine. Checking your vision with an eye chart in the doctor’s office is a screening test. Just because you have trouble reading the eye chart does not necessarily mean that you need glasses. More testing is usually done by a special doctor — an eye doctor. In the same way, if a baby does not pass the hearing screening test, more testing is done by a specialist called an audiologist.

If a baby does not pass the newborn hearing screening test, it is VERY important to make sure the baby gets a follow-up diagnostic test to be SURE that the baby does not have a hearing loss.

Auditory (hearing) Brainstem Response is a test that checks the brain's response to sound and is measured by placing electrodes (non-invasive) on the head to record the brain’s response to sound.

What Is an Otoacoustic Emissions (OAE)?

Otoacoustic Emissions is a test that checks the inner ear response to sound and is measured by placing a very sensitive microphone in the ear canal to measure the ear’s response to sound.

Additional information may be found at www.asha.org/public/hearing/testing.

To understand the difference between Auditory Brainstem Response (ABR) testing and Behavioral Audiometry Evaluation, it is important to understand a little about how the ear works.

The ear has three main parts: the outer ear, the middle ear and the inner ear.

• The outer ear includes the visible portion of the ear and the ear canal. Sound waves travel through these two areas of the outer ear.



• The middle ear includes the eardrum (the tympanic membrane) and three small bones (ossicles). The movement of the tympanic membrane makes the ossicles vibrate.



• The inner ear includes a snail-shaped fluid-filled cochlea, which contains thousands of sound receptors (hair cells). The inner ear is responsible for changing the sound vibrations into electrical signals. The electrical signals are picked up by the hearing (acoustic) nerve. The acoustic nerve sends the sound to the brain.

When an adult or child has a hearing loss, one or more of these parts are not working in the usual way. In order to fully test hearing, all parts of the ear, the acoustic nerve and the brain pathways that are involved in hearing must be tested for proper functioning.

Auditory Brainstem Response (ABR) testing focuses only on the function of the inner ear, the acoustic nerve and the brain pathways that are associated with hearing. This test is used for babies, children and adults. For this test, electrodes are placed on the individual’s head (similar to electrodes placed around the heart when an electrocardiogram is done), and brain wave activity in response to sound is recorded. Because this test does not rely on behavior, the adult or child being tested can be sound asleep during the test.

Behavioral Audiometry Evaluation tests the function of all parts of the ear, including the acoustic nerve and the brain pathways involved in hearing. Infants and toddlers are observed for changes in their behavior such as sucking a pacifier, quieting or searching for the sound. They are rewarded for the correct response by getting to watch an animated toy (this is called visual reinforcement audiometry). Sometimes older children are given a more play-like activity (this is called conditioned play audiometry). The child being tested must be awake and cooperative during this test.

Why Is More Than One Hearing Screening Test Necessary?

Hearing loss in an infant or child cannot be confirmed with one test alone. Several tests must be done to check different parts and different functions of the ear. Audiologists refer to a group of tests as a “battery of tests”. Because Behavioral Audiometry Evaluation tests the function of all parts of the ear, it is considered fundamental to the battery of tests used to evaluate older infants and children for hearing loss. However, because this test relies on behavior and the cooperation of the infant, it is not reliable until the child reaches the developmental age of 5 to 6 months. For children younger than 5 to 6 months of age and for children who are developmentally delayed, ABR testing is considered the most important of these tests.

Source: National Center on Birth Defects and Developmental Disabilities, U.S. Centers for Disease Control and Prevention

Updated: September 1, 2006

Related Articles

• Hearing — Newborn Screening
• Hearing — Understanding Screening Results
• What to Do If Your Baby’s Screening Reveals a Possible Hearing Problem