Tympanometry: What is it and how can it help diagnose?

Whenever you go to the hearing care professional’s office for your annual hearing exam they usually say they want to do “a pressure test”. This test is called tympanometry. It is a very important test used to assess the health of the middle ear. 

 

What the test is?

By presenting a low tone of 226Hz while simultaneously changing the pressure of the eardrum a hearing care professional can learn a lot about the health of a person’s middle ear. The eardrum reacts differently to the changing pressure and the low tone will bounce off the eardrum differently based upon the pressure change. Your hearing care professional will place a small probe with a sanitary tip on the end and place this in your ear. The machine will present the tone and change the pressure with a suitable “seal” that the hearing care professional will obtain. 

 

How to interpret it? 

After the test is completed there are several pieces of information that will be obtained that the hearing care professional will interpret based on standardized norms based on age and gender. Tympanometry gives us information on: 

  • The volume of the ear canal
  • The peak movement of the eardrum at what pressure 
  • The amount of peak movement of the eardrum

These three pieces of information can help a hearing care professional assess the next steps and the health of the system. There is a standardized norm that classifies a tympanogram based on a letter system. 

Type A – This indicates that the volume, pressure, and movement of the eardrum are within normal limits based on age and gender norms. This tympanogram looks like a “mountain” with a notable peak. 

Type B – This indicates that the eardrum movement is not within normal limits based on age and gender norms. This tympanogram will typically look like a flat line or a very shallow peak. 

Type C – This indicates that the eardrum pressure is negative and not within normal limits. This tympanogram looks like a Type A tympanogram but the mountain peak is far off to the left. 

 

Different pathologies that correlate with Tympanometry

From this test a hearing care professional can see: 

  • if there are any perforations or holes in the eardrum
  • any blockage by earwax preventing sound from going in
  • the fluid of the middle ear behind the eardrum
  • The beginning or end of a middle ear infection
  • Disarticulation of the bones of the middle ears 
  • How allergies may be affecting the system

 

It is important to note that Tympanometry is a test that should be used in conjugation with other tests to confirm a diagnosis or pathology. It is, however, an important test to be done during your visit. Visit your local hearing care professional for your annual hearing test or if you have noticed any changes in your hearing.