When you visit an audiologist, multiple tests may be performed to evaluate your ear and hearing health. The audiologist may first look in your ears using an otoscope to check for excessive earwax and confirm that the tympanic membrane (eardrum) is intact. One important test used to further evaluate middle ear health is tympanometry.
Tympanometry is a quick, non-invasive test that provides valuable information about how well your middle ear system is functioning. While it does not measure hearing ability, it plays a critical role in identifying middle ear problems that may affect hearing.
What is Tympanometry?
Tympanometry is a quick, approximately 30-second test that evaluates the health and function of the middle ear and eardrum (tympanic membrane). During the test, a soft rubber probe tip is placed into the ear canal. This probe acts as both a sound source and a microphone.
When the test begins, you will hear a quiet, low-pitched hum and feel slight pressure changes—similar to the sensation you experience during airplane travel. The sound presented is a 226 Hz tone, which travels down the ear canal and reaches the eardrum.
As the sound wave hits the eardrum, the eardrum begins to vibrate, much like a drum being struck. Some of the sound energy is absorbed into the middle ear space, while some is reflected back into the ear canal. The probe measures this reflected sound to assess three key components of middle ear function:
- Tympanic membrane compliance (mobility): How well the eardrum moves
- Ear canal volume: The amount of space between the probe and the eardrum
- Middle ear pressure: The pressure behind the eardrum
Normal values vary by age. Abnormal measurements may suggest conditions such as fluid in the middle ear, earwax blockage, eardrum perforations, or Eustachian tube dysfunction.
How to Interpret Tympanometry Results
Tympanometry results are displayed as a graph called a tympanogram. These graphs typically resemble a mountain-shaped peak or a flat line, depending on middle ear function.
Audiologists classify tympanograms into five main types, a system developed by Dr. James Jerger and widely accepted across audiology practices.
Type A – Normal
A Type A tympanogram indicates normal middle ear function. Tympanic membrane compliance, ear canal volume, and middle ear pressure are all within expected limits.
The graph appears as a clear, sharp mountain-shaped peak. These results suggest that sound is efficiently passing through the middle ear system.
Type As – Stiff or Hypocompliant
Type As tympanograms show reduced eardrum movement, with compliance values of 0.2 cc or less. This means the eardrum is stiffer than normal.
Possible causes include:
- Fluid behind the eardrum
- Scarring of the eardrum
- Stiffening of the middle ear bones
- History of ear surgery or pressure-equalizing tubes
Reduced mobility may require louder sounds to adequately stimulate the inner ear and can sometimes affect hearing.
Type Ad – Hypercompliant
Type Ad tympanograms indicate excessive eardrum movement, with compliance values greater than 1.5 cc. The eardrum moves too easily.
This can occur due to:
- A healed eardrum perforation
- Thinning of the eardrum
- Dislocation of the middle ear bones
In more serious cases, this condition may be associated with hearing loss and may require evaluation by an Ear, Nose, and Throat (ENT) physician.
Type C – Negative Pressure
Type C tympanograms show middle ear pressure values less than –150 daPa, indicating negative pressure behind the eardrum.
This suggests that the eardrum is retracted and may be related to:
- Allergies
- Colds or sinus congestion
- Early or resolving ear infections
- Weather or pressure changes
Type C results are often monitored over time, as they frequently resolve without medical intervention.
Type B – Flat
Type B tympanograms appear flat, showing no measurable eardrum compliance or middle ear pressure.
This typically indicates that the eardrum is unable to move due to:
- Fluid in the middle ear
- Active middle ear infection
- Severe Eustachian tube dysfunction
Type B tympanograms are common in young children because their Eustachian tubes are more horizontal, making fluid buildup more likely. Management may include medication or the placement of pressure-equalizing tubes.
When Should Tympanometry Be Used?
Tympanometry is not performed at every audiology visit. It is most useful when specific symptoms or concerns are present, including:
- Ear pain, fullness, or pressure
- Conductive hearing loss identified during a hearing test
- Sudden changes in hearing
- Following head trauma
- Monitoring middle ear infections or fluid buildup
- Post-surgical evaluation (with appropriate precautions)
The results of tympanometry can help determine whether a referral to an ENT physician is necessary.
FAQs About Tympanometry
What is tympanometry used for?
Tympanometry evaluates middle ear function by measuring eardrum movement, ear canal volume, and air pressure behind the eardrum. It helps identify infections, fluid buildup, perforations, and other middle ear conditions.
Does tympanometry measure hearing loss?
No. Tympanometry does not measure hearing ability. It should always be used alongside a comprehensive hearing test.
Is tympanometry painful?
No. The test is quick and painless, though you may feel brief pressure changes in the ear.
Conclusion: Why Tympanometry Matters
Tympanometry is a simple yet powerful diagnostic tool that helps audiologists evaluate middle ear health. While it does not measure hearing, it provides essential information that completes the overall picture of ear and hearing function.
If you are experiencing ear pain, pressure, fullness, or sudden hearing changes, tympanometry can help identify the underlying cause and guide appropriate treatment. When combined with a full diagnostic hearing evaluation, it plays a vital role in protecting and maintaining long-term hearing health.
Schedule an appointment with your local audiologist today to discuss whether tympanometry is right for you. You can use our Find An Audiologist tool to find one near you!
