Otoacoustic Emissions

Pediatrician checking little girl ears by otoscope

What is an Otoacoustic Emissions (OAE) test?

An Otoacoustic Emission Test (OAE) is the measurement of a sound in the external ear canal called an otoacoustic emission that reflects movement of the outer hair cells in the cochlea. To audiologists, the most important OAEs are the ones that they create intentionally when they perform an OAE test. These OAEs are called Evoked Otoacoustic Emissions (EOAEs). In 1948, Thomas Gold theorized that otoacoustic emissions were possible. He would be surprised today to learn that OAE testing has become a fundamental tool for analyzing hearing in newborns around the world. An OAE test is a non-invasive hearing test that even a fussy child can take.

Why take an OAE test?

 

  • Brief test time: Usually less than a minute per ear, an entire appointment can take less than thirty minutes
  • Simple: Relatively easy technique, painless to take
  • Objective: Uses advanced audio metrology, test is unaffected by attention, cognition, cooperation
  • Independent of age: OAEs can even be recorded from newborn infants
  • Ear specific: Test results for each ear
  • Frequency specific: Information for many individual frequencies

 

What hearing-related applications can OAE testing be used for?

 

Children: 


• Infant hearing screening

• Screening hearing in pre-school (e.g., Head Start) years

• Screening in school age children

• Monitoring for possible ototoxicity (poisons affecting the ear)

• Diagnosis of pediatric hearing impairment
Adults:

• Screening for cochlear (outer hair cell) hearing loss

• Screening for occupational or recreational noise induced cochlear dysfunction

• Monitoring for possible ototoxicity (poisons affecting the ear)

• Differentiation of organic versus non-organic hearing loss

• Diagnostic assessment of tinnitus

• Diagnosis of auditory dysfunction adults

 

What does an OAE test feel like?

If you need to take an OAE test, relax. It is easy and fast. Below you can learn the details of how the hassle-free technology works when you take the test.

First, a soft disposable probe tip is placed in your ear canal. A miniature speaker in the probe generates a painless, sound stimulus that is moderately intense and tuned to a specific frequency. The impact of the stimuli vibrates your ear drum, transmitting mechanical energy through your middle ear to the cochlea. Now imagine that small waves are created in the cochlear fluids which vibrate a thin membrane that activates outer hair cells located on the membrane.
Energy associated with outer hair cell movement, in the frequency region of the stimulus, is generated back through the middle ear system and into the ear canal. This is the OAE event. A miniature microphone within the probe assembly detects the OAE-related sound, as well as any other sound in the ear canal during the recording.
Using a series of math formulas, the OAE activity is separated from random noise to reveal the pure signal of the OAE, which can be compared to standard clinical events for analysis by your audiologist. For most, the test will take less than thirty minutes. It is easy, automatic and precise.