Newborn hearing screening is a routine, non-invasive examination performed shortly after a baby’s birth to identify potential hearing difficulties. Most babies undergo this universal screening before leaving the hospital. The process is gentle, taking only a few minutes, often while the baby is sleeping.
Why Early Hearing Screening Matters
Early detection of hearing loss in newborns is important for a child’s overall development. Undetected hearing loss can impact speech, language, social skills, and cognitive abilities. Early identification allows for timely intervention, which improves a child’s developmental outcomes.
Interventions initiated within the first few months of life can help mitigate potential developmental delays. Support services can be put in place to help the child acquire communication skills. This proactive approach supports healthy development and integration.
How Newborn Hearing Tests Work
Two primary types of tests are used for newborn hearing screening: Automated Auditory Brainstem Response (AABR) and Otoacoustic Emissions (OAE). Both methods are safe and comfortable for the baby. Hospitals select the screening method based on various factors, including cost, available personnel, and the number of births.
Automated Auditory Brainstem Response (AABR) testing measures how the hearing nerve and brainstem respond to sounds. During an AABR test, small electrodes are placed on the baby’s head, on the forehead and behind each ear. Soft earphones are then placed in or around the baby’s ears to deliver gentle sounds.
The electrodes detect the electrical activity generated by the auditory pathway, and a computer analyzes these responses to determine if hearing is functioning as expected. This test can take approximately 15 to 60 minutes and is preferred for babies who have spent more than five days in the neonatal intensive care unit (NICU). AABR is more tolerant of small amounts of fluid in the ear, making it less likely to produce a “refer” result when no hearing problem exists.
Otoacoustic Emissions (OAE) testing measures sounds produced by the inner ear, specifically the cochlea, in response to auditory stimulation. For an OAE test, a small earphone with a microphone is placed into the baby’s ear canal. The earphone emits soft sounds, and if the inner ear is functioning normally, it produces a faint “echo” or emission that the microphone detects.
If a baby has significant hearing loss, no echo or a reduced echo will be measured. This test is quicker, taking less than 30 seconds per ear, and is performed while the baby is calm or sleeping.
While efficient, OAE testing primarily assesses the cochlea and does not evaluate higher-level auditory structures like the hearing nerve or brainstem. Factors such as fluid in the ear canal, excessive movement, or environmental noise can sometimes lead to a “refer” result even if no hearing loss is present.
Interpreting Test Results
Newborn hearing screening results are presented as either a “pass” or a “refer.” A “pass” result indicates the baby’s hearing is within the typical range; their ears and auditory pathways responded as expected to the test sounds.
A “refer” result means further testing is needed. A “refer” does not automatically mean the baby has permanent hearing loss. Factors such as fluid in the ear canal, a restless baby during the test, or a noisy testing environment can influence the outcome and lead to a “refer” result. This means the initial screening requires a more comprehensive evaluation to confirm hearing status.
What Happens After a Referral
If a baby receives a “refer” result from the initial hearing screening, the next step is to schedule a follow-up diagnostic appointment with an audiologist. An audiologist is a healthcare professional specializing in hearing assessment and management. This follow-up appointment should occur within 2 to 4 weeks after the baby’s discharge from the hospital.
During the diagnostic appointment, the audiologist will conduct more comprehensive tests to pinpoint the nature and extent of any hearing difference. These tests might include a more detailed AABR or other specialized audiological evaluations suitable for infants. Even if hearing loss is confirmed, early intervention services and support are available to help the child develop communication skills and thrive.