What is an OAE (Otoacoustic Emissions) Hearing Test?

Newborn baby having hearing test
Hisham Ibrahim/Getty Images

What is an OAE (Otoacoustic Emissions) Hearing Test?

OAE stands for otoacoustic emissions, the name for the sounds produced by the cochlea. These sounds can be used to test the function of the cochlea (specifically hair cell function) and other parts of the ear, including the auditory nerve.

Why is OAE Used?

Otoacoustic Emissions Hearing tests are usually performed on newborn babies to detect deafness.

The test can also partially estimate hearing sensitivity and test for functional hearing loss. Functional hearing loss is also sometimes referred to as non organic hearing loss and is a condition where you have symptoms or behaviors of hearing loss but there is nothing actually wrong with your hearing. Some sources might refer to this as feigned hearing loss but that's probably not completely accurate as this implies that someone is "faking it" and this type of hearing loss has multiple origins that are not always within an individuals control.

Otoacoustic Emissions Hearing tests are commonly used in conjunction with the ABR (Auditory Brainstem Response) hearing test or other hearing tests.

How is OAE Performed?

Otoacoustic Emissions Hearing testing is not painful and many babies sleep right through it. Small probes are placed in the ear. One delivers sound and the other is a microphone. If the cochlea is functioning properly it should echo in response to the sound.

There are four types of sounds that the cochlea produces:

  1. Spontaneous acoustic emissions - the cochlea produces these sounds spontaneously (not in response to another sound). These only occur in approximately 40-50 percent of people with normal hearing.
  2. Transient otoacoustic emissions - produced in response to another sound of short duration (transient). Usually clicks or tone-bursts. These are commonly used to evaluate hearing in infants.
  1. Distortion product otoacoustic emissions - produced in response to two simultaneous tones of different frequencies. These are particularly useful in detecting damage to the cochlea early on (for example damage to the cochlea from ototoxicity or noise induced damage).
  2. Sustained - frequency otoacoustic emissions - produced in response to a continuous tone. These are not typically used in the clinical setting.

Some conditions can cause the absence of OAE's. These include: cysts, external otitis (swimmer's ear for example), stenosis, or abnormal middle ear pressure, a perforated ear drum, otosclerosis, cholesteatoma.

OAE testing cannot definitively diagnose hearing loss or deafness. If you fail OAE testing you will need further hearing tests to determine if there is hearing loss or not.

Sometimes OAE testing is inaccurate because an infant is fussy during the test and sometimes babies have fluid in their ears or other conditions that can cause them to fail the test even though they do not have any permanent hearing loss.

Other factors that can cause OAE testing to fail or be inaccurate include:

  • Poor seal around the ear probes.
  • Ear wax blockage, especially if it prevents getting a good seal around the ear probe.
  • Debris or foreign objects in the ear canal.
  • An uncooperative patient.

Sources:

Medscape. Otoacoustic Emissions. Accessed: February 29, 2016 from http://emedicine.medscape.com/article/835943-overview

NDCS. Newborn Hearing Screening. Accessed: May 28, 2010 from http://www.ndcs.org.uk/family_support/newborn_hearing_screening/index.html#contentblock2

Utah Department of Health. Children With Special Health Care Needs. Otoacoustic Emission Screening. Accessed: May 26, 2010 from http://health.utah.gov/cshcn/SVS/otoacoustic.html

Continue Reading