The newborn hearing screening is a universal public health program designed to identify potential hearing loss in infants shortly after birth. Early identification is necessary because a baby’s brain requires sound input to develop the neural pathways for speech and language acquisition. Nearly every newborn in the United States receives this safe and non-invasive screening before being discharged from the hospital or birthing center, often within the first two days of life.
Understanding the Tests Used
The screening is not a single test but typically involves one of two different physiological measurements to check how the baby’s auditory system responds to sound. These tests rely on the baby being calm, quiet, or asleep to minimize interference from movement or environmental noise. The first method is the Otoacoustic Emissions (OAE) test, which uses a small probe placed in the ear canal to play a soft sound. The microphone in the probe then listens for a faint echo that is generated by the outer hair cells of the inner ear, or cochlea, when they are stimulated by sound.
A healthy cochlea produces this measurable echo, confirming that the inner ear is functioning correctly in response to the sound stimuli. If a baby has a significant hearing loss, this echo will be absent or reduced, causing the screening device to register a “Refer” result. The second common method is the Automated Auditory Brainstem Response (AABR) test, which measures the electrical activity along the hearing nerve and brainstem as sound travels from the ear to the brain. For the AABR, small electrodes are placed on the baby’s head, and sounds are delivered through earphones.
The electrodes record the brain’s response to the sound, which indicates whether the auditory pathway is transmitting the signal effectively. The AABR screening is often utilized in high-risk nurseries, such as the Neonatal Intensive Care Unit (NICU), because it can detect certain types of hearing loss related to the nerve pathways that the OAE test might miss. Both the OAE and AABR are quick screening tools that provide a simple “Pass” or “Refer” outcome, not a detailed audiogram.
Interpreting Pass and Refer Outcomes
The results of the newborn hearing screening are reported as either a “Pass” or a “Refer.” A “Pass” result means that both of the baby’s ears responded within the normal range at the time of the screening, suggesting hearing is likely typical. This outcome is what most parents receive, and it typically concludes the screening process unless the child has risk factors for later-onset hearing loss.
If the result is a “Refer,” it means the baby did not pass the screening in one or both ears and requires further testing. It is important to understand that a “Refer” does not mean the baby has permanent hearing loss. Screening tests are designed to be highly sensitive, meaning they cast a wide net to ensure no hearing loss is missed, which inevitably leads to a number of false-positive results. In fact, between 2 and 10 percent of newborns refer on their initial screening, but less than 1 percent of all babies have permanent hearing loss.
The most frequent reasons for a “Refer” result are temporary and unrelated to a true hearing impairment. Residual fluid or vernix, the waxy coating on a newborn’s skin, can remain in the ear canal or middle ear after birth, blocking the sound or the echo response. Excessive movement, crying, or even background noise during the brief test can also interfere with the sensitive equipment’s ability to get a clear measurement. In these common scenarios, the ear canal or middle ear simply needs more time to clear itself of fluid or debris.
Necessary Follow Up After a Refer Result
If the baby receives a “Refer” result on the initial screening, follow-up is necessary to determine the true status of their hearing. The standard protocol for Early Hearing Detection and Intervention (EHDI) programs recommends a rescreening or a comprehensive diagnostic evaluation be completed by the time the baby is three months old. The first step is often a rescreening, which may be conducted by an outpatient audiologist, and this should ideally occur within the first month after discharge.
If the baby passes the rescreening, the process is complete, and no further immediate action is required. However, if the baby refers a second time, a full diagnostic audiological evaluation must be scheduled immediately. This thorough testing is performed exclusively by a pediatric audiologist, a specialist trained to evaluate and manage hearing loss in children. The diagnostic evaluation is far more comprehensive than the initial screening and will determine the specific type, degree, and configuration of any hearing loss.
The audiologist will use diagnostic ABR, which is a detailed version of the screening test, along with other specialized tests, to measure the softest sounds the baby can hear at different frequencies. This evaluation is typically performed while the baby is asleep, and it provides the first definitive diagnosis of hearing status. Following the recommended timeline is important, as any hearing loss confirmed by the three-month mark must have intervention services, such as hearing aids or other support, started no later than six months of age to maximize language outcomes.