Otoacoustic emissions (OAE – Otoacoustic Emissions) are an objective hearing test used primarily to assess the function of the inner ear. These emissions provide an accurate and reliable measurement for detecting hearing loss and are particularly important for early diagnosis in infants and young children. In this post, we explain what otoacoustic emissions are, how the test is performed and what the results tell us.
What Are Otoacoustic Emissions (OAE)?
Otoacoustic emissions are sounds produced by the hair cells of the inner ear as they process the sounds reaching the ear. These cells, located in the cochlea, move in response to sound stimuli and produce a returning sound, which is recorded and analysed by the OAE test equipment. This response is a sign of a healthy cochlea and indicates that hearing is preserved.
How Does the Otoacoustic Emissions Test Work?
- Preparing the patient
The otoacoustic emissions test is quick and painless. The patient stays still and, in the case of infants, the test is often carried out while they are asleep. The outer ear is cleaned to make sure there is nothing that could affect the accuracy of the measurement. - Placing the probe in the ear
A small probe is gently inserted into the patient's ear canal. This probe delivers sound stimuli into the ear in the form of clicks or other short tones. - Recording the cochlear response
The OAE device records the response produced by the hair cells of the cochlea. If the cochlea is working properly, it will produce a returning sound that is picked up by the probe. - Interpreting the results
If the cochlea does not respond to the stimuli delivered, this may indicate a problem with the hair cells or a hearing loss that affects the ear's ability to process sound. The OAE test clearly shows how the inner ear is functioning and is used to distinguish whether hearing loss is related to the cochlea or to other structures of the auditory system.
Why Are Otoacoustic Emissions Used?
The OAE test is particularly valuable for:
- Assessing hearing in infants and young children: Otoacoustic emissions are the most suitable way to test infants, who cannot give subjective responses. This test is often performed in the first days after birth to detect any hearing problem early.
- Screening high-risk populations: Because it is quick and non-invasive, OAE is used to test groups at higher risk of hearing loss, such as children who have had repeated ear infections, those exposed to medications that can damage hearing, or those with a family history of hearing problems.
- Assessing cochlear health: For people with middle ear problems, such as a blockage of the ear canal or other infections, OAE helps confirm whether the cochlea is working properly, allowing the audiologist to better determine the type of hearing loss.
What Results Can Be Expected from an OAE Test?
OAE test results fall into two main categories:
- Otoacoustic emissions present: When the cochlea is working properly and the hair cells respond normally to the stimuli, the test will show that otoacoustic emissions are present. This result suggests that the inner ear is processing sound normally and that hearing is healthy.
- Otoacoustic emissions absent: If no otoacoustic emissions are recorded, this may indicate a problem in the inner ear. The lack of a response may mean damage to the hair cells of the cochlea or a hearing loss that requires further assessment to determine the cause and extent of the problem.
Benefits of the Otoacoustic Emissions (OAE) Test
- Non-invasive and quick: The test is completely painless and usually takes only a few minutes, which makes it ideal for infants and young children.
- High accuracy in detecting cochlear problems: OAE is highly effective at detecting hearing loss related to cochlear damage, helping to identify disorders that may affect language and speech development.
- Suitable as an initial screening tool: OAE is often the first step in assessing hearing and is widely used in newborn screening programmes in hospitals and paediatric clinics.
What Happens After the OAE Test?
If the OAE results show that otoacoustic emissions are present, this usually rules out significant hearing loss, and the infant is considered to have healthy hearing. However, if the results show that otoacoustic emissions are absent, the audiologist may recommend additional tests to determine the degree of hearing loss and the most appropriate treatment.
Conclusion
Otoacoustic emissions are an important method for the early detection of hearing problems, particularly in infants and young children who cannot give subjective responses. This quick and painless test plays an important role in diagnosing hearing loss and in ensuring early intervention to support a child's healthy language and social development. If you have further questions about otoacoustic emissions, speak with your audiologist for additional guidance and explanations.