Acoustic Reflex Testing

If you are experiencing symptoms of hearing loss, it is essential to have your hearing checked without delay. There are many types of examinations to screen for hearing loss, and you will likely be prescribed a series of them. Each hearing test measures different parts of your ear to look for different types of hearing problems. The examinations you will be prescribed will be determined by a hearing professional and will depend on the specific symptoms of your hearing loss.

We know that the words "hearing test" can be quite daunting when you don't know what to expect. That's why we've gathered resources that allow you to easily learn about each of the different types of hearing tests. In this particular article, we detail everything you need to know about the acoustic reflex test.

What is the acoustic reflex test and how does it work?

There is a small muscle in your middle ear that contracts involuntarily when stimulated by a loud noise. This contraction is called the "acoustic reflex." The louder the sound needs to be to trigger the acoustic reflex, the more impaired your hearing is. The reason this reflex exists in our ears is to reduce the intensity of our own voice when we speak. Indeed, we hear ourselves louder than we hear others. We perceive our own voice through both air conduction and bone conduction, which is why we hear it so differently from other people's voices; it's also why so many people dislike the sound of their own voice. In summary, our acoustic reflex exists to protect us from the intensity of our own voice.

The acoustic reflex test is a sub-test of tympanometry. In other words, the acoustic reflex can only be assessed during a tympanometry examination. Individuals with a normal tympanogram are re-tested with the acoustic reflex test to precisely locate the origin and nature of their hearing impairment. However, while tympanometry varies air pressures to assess the function of the eardrum, the acoustic reflex test uses a fixed air pressure during which sound is sent to the eardrum. The equipment and procedure for the acoustic reflex test are exactly the same as for tympanometry: a tympanometer probe is placed in your ear and you feel some air pressure in the ear canal, but the sensation should not be painful. The results of the acoustic reflex test appear as a kind of curve on the tympanogram. The goal is for the acoustic reflex curve to be smaller than the initial curve of the normal tympanogram.

Why test the acoustic reflex?

The acoustic reflex involves a large part of the ear, including the brainstem, inner ear, middle ear, outer ear, and so on. Thus, most of the auditory pathways are assessed during an acoustic reflex test. Any problem in any of these parts of the auditory pathways will appear in the acoustic reflex test and help identify the type and underlying cause of a patient's hearing loss.

Conclusion

The acoustic reflex is assessed during a tympanometry examination, using a tympanometer that measures the function of different parts of the auditory pathways. Your hearing professional can determine which parts of the auditory pathways are not functioning correctly from the results of the tympanogram. This will help them precisely identify the underlying cause and type of hearing loss you are experiencing.

Thank you for reading this article,

Kathleen Williams

Editor-in-Chief, CLARIA