What otoacoustic emissions testing measures

Otoacoustic emissions (OAE) testing detects sound waves produced by the inner ear in response to clicks or tones played through a small probe in the ear canal. The test does not measure how well you hear; it measures whether the hair cells in your cochlea—the spiral-shaped part of the inner ear—are functioning. A healthy inner ear produces these emissions automatically. A damaged or absent inner ear does not.

The probe sits just inside your ear canal and sends brief sounds while a sensitive microphone records any echoes coming back. The entire test takes five to ten minutes per ear and produces no discomfort. You do not need to respond or press a button. The machine records the data and displays whether emissions were detected.

OAE testing is one of the few tests that can detect hearing loss before a person notices symptoms, which is why it is the standard screening tool for newborns in most U.S. hospitals. It is also used to monitor people taking medications known to damage hearing and to investigate sudden hearing loss in adults.

Key Takeaways

  • OAE testing measures inner ear function by detecting sound waves the ear produces naturally, not by measuring how well you hear sounds.
  • The test takes five to ten minutes, requires no response from you, and is painless, making it ideal for newborns and people who cannot follow verbal instructions.
  • A normal OAE result suggests the cochlea is working; an absent result may indicate hearing loss, fluid in the ear, or earwax blockage.
  • OAE testing cannot pinpoint the cause of hearing loss or measure how severe it is—those require additional tests like audiometry or imaging.
  • Newborns who do not pass OAE screening are referred for follow-up testing within a few weeks, not when ready diagnosed with permanent hearing loss.

Why OAE testing is used for newborn screening

Hospitals perform OAE testing on newborns because early detection of hearing loss changes outcomes. A child identified with hearing loss in the first few months of life can begin intervention—hearing aids, cochlear implants, or sign language instruction—during the critical window when the brain is developing language. Children who do not receive early intervention often fall behind in speech and academic development.

OAE testing works for newborns because it requires no behavioral response. A baby does not have to turn toward a sound or raise a hand. The test straightforward records whether the ear is producing emissions. This makes it faster and more reliable than behavioral tests, which depend on an infant's attention and cooperation.

Most U.S. states require newborn hearing screening before hospital discharge or within the first month of life. The specific test—OAE, auditory brainstem response (ABR), or both—varies by hospital and state program. If a newborn does not pass the initial OAE screening, the hospital schedules a follow-up test, usually within two to four weeks. A single failed screening does not mean permanent hearing loss; many newborns fail initially because of fluid in the ear canal or earwax, which clears on its own.

How OAE results are interpreted

OAE machines produce a straightforward pass or refer result. A pass means the microphone detected emissions at the expected levels, suggesting the cochlea is functioning. A refer result means emissions were not detected or were below the threshold, which prompts further testing.

A refer result does not diagnose hearing loss. It signals that something may be wrong—but that something could be permanent hearing damage, temporary fluid in the middle ear, earwax, a probe that did not seal properly, or background noise during the test. For this reason, anyone who receives a refer result on OAE testing should have a follow-up test, usually ABR (auditory brainstem response) testing or a repeat OAE in a quieter setting.

In newborns, a refer result on the first screening often resolves on its own. The middle ear is still clearing fluid from birth, and a second test a few weeks later frequently shows a pass. If the refer result persists across multiple tests, or if ABR testing shows abnormality, the child is referred to an audiologist for comprehensive evaluation and possible intervention.

OAE testing versus other hearing tests

OAE testing is one tool in a larger toolkit. It tells you whether the inner ear is producing sound, but it does not tell you how loud a sound has to be for someone to hear it, whether the middle ear is working, or where in the hearing system a problem exists.

Auditory brainstem response (ABR) testing measures electrical activity in the brain in response to sound. It can estimate hearing thresholds—the quietest sound a person can detect—and works for people of any age, including those who cannot follow instructions. ABR is often used alongside or instead of OAE in newborn screening programs.

Audiometry is the standard hearing test for children and adults who can respond to sounds. A person sits in a soundproof booth and raises a hand or presses a button when they hear tones at different volumes and frequencies. Audiometry produces a detailed picture of hearing loss across the frequency range but requires active participation.

OAE testing is faster and requires no response, which makes it ideal for screening large populations and for people who cannot cooperate with behavioral tests. But because it only detects whether the cochlea is working, it is almost always paired with another test to confirm results and measure the degree of hearing loss.

When OAE testing is used in adults

OAE testing in adults is less common than in newborns but serves specific purposes. People taking ototoxic medications—drugs that can damage hearing, such as certain antibiotics, chemotherapy agents, or loop diuretics—may have OAE testing at baseline and during treatment to detect early cochlear damage before symptoms appear.

OAE testing is also used to investigate sudden hearing loss. If a person wakes up with hearing loss in one ear, OAE testing can quickly show whether the cochlea is still functioning. A normal OAE result in the affected ear suggests the problem lies elsewhere—in the middle ear, the auditory nerve, or the brain—and prompts imaging or other tests. An absent OAE result suggests cochlear damage and may lead to urgent treatment with steroids or other interventions.

In occupational settings, some employers use OAE testing as part of hearing conservation programs to monitor workers exposed to loud noise. Because OAE is objective and fast, it can screen many workers in a short time without requiring them to sit in a booth or follow complex instructions.

Limitations and reasons for false results

OAE testing is reliable but not perfect. Several factors can produce a refer result even when hearing is normal. Earwax or debris in the ear canal can block the probe seal, preventing the microphone from recording emissions. Fluid in the middle ear—common in newborns and people with ear infections—can dampen the sound traveling to the cochlea. Background noise in the testing room can mask the faint emissions the machine is trying to detect.

The probe itself must seal properly in the ear canal. If the seal is loose, emissions escape and the machine records nothing. Newborns and people with very small or unusually shaped ear canals may be harder to test. A skilled technician can usually overcome these problems by cleaning the ear, repositioning the probe, or testing in a quieter environment.

OAE testing also cannot detect all types of hearing loss. It measures only cochlear function. Hearing loss caused by damage to the auditory nerve, the middle ear bones, or the eardrum will not show up as an absent OAE if the cochlea itself is still working. This is why a normal OAE result does not rule out all hearing problems, and why a refer result always requires follow-up testing to determine the actual cause.

What happens after OAE testing

If you or your child passes OAE screening, no further action is needed unless hearing loss develops later. Newborns who pass are considered to have normal cochlear function at the time of testing.

If the result is refer, the next step depends on your age and the clinical context. Newborns are scheduled for a repeat OAE or ABR test within two to four weeks. Many newborns pass on the second test because middle ear fluid has cleared. If the refer result persists, the child is referred to an audiologist for comprehensive testing and evaluation.

Adults who receive a refer result should see an audiologist or ear, nose, and throat (ENT) doctor. They will perform additional tests—usually audiometry and possibly imaging—to identify the cause of the refer result and determine whether hearing loss is present and how severe it is.

Frequently Asked Questions

Can earwax cause a refer result on OAE testing?

Yes. Earwax or debris in the ear canal can prevent the probe from sealing properly, which blocks the microphone from detecting emissions. If earwax is suspected, the ear can be cleaned and the test repeated. A refer result caused by earwax alone will usually become a pass after cleaning.

Does a normal OAE result mean my child's hearing is perfect?

A normal OAE result means the cochlea is producing sound waves, which is a good sign. However, OAE testing does not measure how loud sounds need to be for your child to hear them, and it does not detect all types of hearing loss. If you have concerns about your child's hearing development, discuss them with your pediatrician or audiologist.

What if my newborn fails OAE screening—does that mean they are deaf?

No. A refer result on newborn OAE screening does not diagnose deafness or permanent hearing loss. Many newborns refer because of fluid in the ear canal, which clears within weeks. A second test usually shows a pass. If the refer result persists, your child will be referred for more detailed testing to determine whether hearing loss is actually present.

How is OAE testing different from a regular hearing test?

OAE testing measures whether the inner ear is producing sound; a regular hearing test (audiometry) measures how well you can hear sounds at different volumes. OAE is objective and requires no response from you. Audiometry requires you to respond when you hear a sound. Both tests provide different information and are often used together.

Can OAE testing detect hearing loss caused by nerve damage?

No. OAE testing measures only cochlear function. Hearing loss caused by damage to the auditory nerve, the middle ear, or the eardrum will not show up as an absent OAE if the cochlea is still working. If nerve damage is suspected, ABR testing or imaging may be needed to investigate further.