According to the National Conference of State Legislatures, all states in the U.S. sponsor hearing-screening programs for newborns. Although 14 states allow exemptions from screening if parents object, the vast majority of parents will take advantage of this important opportunity.
In the past, only infants considered at risk for hearing loss were screened. Even so, subsequent studies indicated that despite the testing of high-risk children, over half of all newborns with hearing loss were not identified.
Hearing screenings are painless and can be done quickly, especially for children who are born in hospitals. Parents who give birth at home or in a birthing center should make it a priority to have their newborn screened for hearing loss in the first few weeks after birth.
Why Is Hearing Screening Important?
Studies show that if hearing loss is identified before a child is six months old, that child has a better chance of developing skills at the same level as non-hearing-impaired children by the time of entry into kindergarten. Children whose hearing impairment is not identified until later in life are less likely to keep pace with their peers, and will have trouble developing abilities that are associated with hearing, like language skills and cognitive thinking abilities. The National Institutes of Health, the American Academy of Otolaryngology/Head and Neck Surgery, and the American Academy of Pediatrics all agree on the importance of early screening.
How Is the Test Performed?
An infant hearing test is simple and usually takes about 15 minutes. There are two different methods; both are effective and painless. The choice of method depends on the testing organization’s equipment and the way its personnel have been trained.
- Auditory brainstem response (ABR) evaluations measure the reaction of the infant’s brain stem to sound. In the normal hearing process, sound is sent to the brain stem from the ear, and the ABR assesses how efficiently this is completed. First, small electrodes are placed on the child’s head. Then, using earphones, sounds are generated to nerves in the baby’s ears, which in turn send electrical impulses to the brain stem. The brain’s electrical response to those impulses is measured by the electrodes and presented in graph form for analysis by experts.
- Otoacoustic emission (OAE) tests measure an acoustic response to sound that is produced by the inner ear. First, a small probe is placed into the infant’s ear. Then, sounds are generated in the probe, which sends electrical stimuli to the brainstem. Up until this point, the OAE is much like the ABR. However, with the OAE, a second sound is created that bounces back out of the infant’s ear. The reaction to this second sound, called an emission, is then recorded for analysis.
What Causes Hearing Loss in Infants?
Hearing loss can be triggered by a wide range of factors, but the underlying cause of most permanent hearing loss is some type of malfunction of the auditory nerve, the main nerve that transmits sound from the inner ear to the brain. Sometimes the trigger cause is never identified, but in about half of all cases, it’s the result of some type of genetic condition.
Nongenetic causes of hearing impairment in newborns include deformities of the ear, particularly its internal structures, low birth weight, and prematurity. A serious infection contracted by a woman during pregnancy can also cause hearing problems in an infant, as can viral illnesses like rubella.
What If My Infant Doesn’t Pass the Screening Test?
Infants who fail the hearing test are, along with the parents, referred to a physician or medical facility that specializes in infant hearing loss. Sometimes the problem is relatively easy to correct, such as when fluid from the birth is trapped in the inner ear, or when surgery can be performed to correct a malformation of the ear’s structure. In other instances, the treatment process is more complex, and can last for extended periods of time.
There are many effective treatments for infants with hearing loss, and these therapies are often successful in ensuring appropriate development of speech, language, cognition, and other abilities. An infant’s chances of living a full and productive life are greatly increased when hearing is assessed immediately after birth and appropriate steps are taken to address any problems.