Most newborns have their hearing tested within the first few days of life, usually before leaving the hospital. The screening is painless, takes just a few minutes, and can be done while the baby sleeps. If your child hasn’t been screened yet, or if you’re trying to understand what a “refer” result means, here’s how each type of infant hearing test works and what comes next.
The 1-3-6 Timeline
National guidelines recommend three benchmarks for catching hearing loss early. Babies should be screened by 1 month of age, receive a diagnostic evaluation by 3 months if they don’t pass the screen, and be enrolled in early intervention services by 6 months. Following this timeline gives children with hearing loss the best chance of developing communication and language skills on pace with their peers.
How Newborn Screening Works
Hospitals use two types of screening tests, sometimes one after the other. Neither requires the baby to do anything, and both are completely painless.
Otoacoustic Emissions (OAE)
A tiny earpiece is placed in the baby’s ear canal and plays soft sounds. A healthy inner ear responds by producing its own faint sounds, which the device picks up. The test specifically checks whether the outer hair cells of the cochlea (the hearing organ in the inner ear) are working. It takes about four minutes on average and gives a quick pass or refer result.
The main limitation is a relatively high false-positive rate, ranging from about 1% to nearly 20% depending on the setting. Leftover fluid and tissue in the middle ear from birth can block the sound the device is trying to detect. A “refer” result in the first day or two of life often reflects this temporary fluid rather than a true hearing problem. OAE screening also cannot detect a specific condition called auditory neuropathy, where the inner ear works normally but the signal traveling from the ear to the brain is disrupted. A baby with auditory neuropathy will pass OAE screening.
Automated Auditory Brainstem Response (AABR)
Small sensors are placed on the baby’s forehead and behind each ear. Soft clicking sounds play through earphones while the sensors measure the electrical activity in the auditory nerve and brainstem. This test checks the entire pathway from the ear to the brain, which means it can catch auditory neuropathy that OAE would miss. It takes longer, averaging about 12 to 13 minutes, and has a lower false-positive rate than OAE.
AABR is recommended for babies who spent time in the NICU or who have other risk factors for hearing loss, precisely because it covers that nerve pathway. Some hospitals use AABR as the primary screen for all newborns; others use OAE first and follow up with AABR if the baby doesn’t pass.
What Happens After a “Refer” Result
A “refer” result means the baby needs further testing. It does not mean the baby has permanent hearing loss. Many babies who are referred on the initial screen turn out to hear normally once the fluid in their ears clears or the test is repeated under better conditions.
If the baby doesn’t pass the rescreen, the next step is a diagnostic auditory brainstem response test, which is a more detailed version of AABR. Small electrodes are placed on the scalp and earlobes while the baby sleeps naturally or, for older infants, under light sedation. The audiologist plays both broadband clicks and tone bursts at specific frequencies (typically 500, 1000, 2000, and 4000 Hz) to map out exactly which pitches the baby can hear and at what volume. This produces results similar to the hearing test adults get in a sound booth, but without needing the baby to raise a hand or press a button.
Middle Ear Testing in Young Infants
Audiologists often check the middle ear using a test called tympanometry, which measures how the eardrum moves in response to gentle air pressure changes. For adults and older children, this test uses a standard low-frequency tone. For babies under six months, it doesn’t work well. The ear canal wall and eardrum of a young infant are softer and more flexible than an older child’s, and the middle ear is still developing: the ear canal is still ossifying, the eardrum’s fiber structure is changing, and residual fluid from birth may linger. These differences distort the results when a standard probe tone is used.
Instead, audiologists use a higher-frequency 1000 Hz probe tone for infants under six months. This frequency matches the acoustic properties of the immature middle ear much more accurately and can reliably detect conditions like fluid buildup that might be affecting hearing.
Behavioral Hearing Tests for Older Infants
Once a baby is old enough to turn their head reliably, audiologists can start using behavioral tests that measure what the child actually perceives.
Visual Reinforcement Audiometry (5 to 24 Months)
This test works for babies with a developmental age of at least five to seven months. The baby sits on a parent’s lap in a sound booth. When a sound plays, the audiologist watches for the baby to turn toward it. Each correct head turn triggers a visual reward, usually a lit-up toy or animated display near the speaker. After a few rounds, the baby learns the game: hear a sound, turn your head, see something fun. The audiologist then gradually lowers the volume to find the softest level the baby responds to at different pitches.
Conditioned Play Audiometry (2 Years and Up)
Starting around 24 months, children can learn to do a simple task each time they hear a sound. They might drop a block into a bucket, place a peg in a pegboard, or put a puzzle piece in place. The audiologist demonstrates the game four or five times until the child catches on, often with clapping or praise as encouragement. This technique can provide frequency-specific results for each ear separately, similar to a standard adult hearing test. For toddlers with short attention spans, audiologists will alternate between ears to get at least partial information from both sides rather than risking a complete test on only one ear.
Hearing Milestones to Watch For
Even if your baby passed the newborn screen, hearing loss can develop later. Knowing what to expect at each stage helps you spot potential problems early.
From birth to three months, babies should startle at loud sounds and turn their head toward your voice when you speak. Between four and six months, they should look or turn toward new sounds in their environment. By nine to twelve months, most babies begin responding to their name, babbling with varied sounds, and reacting to simple words like “no.” If your child doesn’t seem to hit these milestones, or if you notice a change in how they respond to sound after an illness or ear infection, a hearing evaluation is warranted regardless of earlier screening results.
Risk Factors That Call for Ongoing Monitoring
About 50% of children with permanent congenital hearing loss have at least one identifiable risk factor. The most significant include a family history of hearing loss, time in the NICU, low birth weight, congenital infections (particularly cytomegalovirus, which accounts for 5% to 20% of congenital hearing loss cases), craniofacial differences, severe jaundice, and low Apgar scores at birth. Babies who needed ventilator support, received certain medications that can affect hearing, or had meningitis or sepsis also carry higher risk.
Genetic factors are the single most common cause, responsible for roughly half of permanent congenital hearing loss. Many of these cases have no other visible signs, which is one reason universal screening at birth is so important. For babies with any known risk factor, periodic hearing evaluations through early childhood are recommended even after a normal newborn screen, because some forms of hearing loss are progressive or delayed in onset.