Tympanometry is a diagnostic test used to assess the health of the middle ear and the mobility of the eardrum and the adjoining chain of bones. It’s often carried out as part of a hearing assessment, and is particularly useful for diagnosing otitis media with effusion, a perforated eardrum, Eustachian tube dysfunction, and other problems related to middle ear pressure.
To carry out tympanometry, a device called a tympanometer sends a sound into the ear canal. At the same time, it varies the pressure in the ear canal and measures how much sound bounces back off the eardrum. The eardrum normally vibrates more when air pressure is equal on both sides of the middle ear. The eardrum’s response to pressure changes is recorded on a graph called a tympanogram, which the audiologist can interpret to identify problems.
In the chart accompanying this article, you can see different types of tympanometric curves representing different middle ear conditions.
Types of tympanometric curves
- Normal ear: A type “A” curve shows normal mobility of the eardrum and ossicular chain, indicating a middle ear free of fluid and with normal pressure.
- Simple tubal obstruction: A flat curve, or type “B”, with no clear peak in mobility, suggests there’s fluid in the middle ear, as could happen with a middle ear infection without a perforated eardrum.
- Tubal obstruction with fluid in the middle ear: Similar to the type “B” curve, but it may show a slight slope, indicating there’s a fluid effusion and the Eustachian tube is blocked.
- Middle ear fully blocked by discharge: This curve can look like a type “B” curve, but with points where mobility is somewhat better, which can happen in acute middle ear infections.
- Otosclerosis or ossicular chain dysfunction: A type “As” curve indicates reduced mobility of the eardrum and ossicular chain, which can happen with otosclerosis.
- Ossicular chain disruption or disconnection: A type “Ad” curve shows excessive mobility of the eardrum and ossicular chain, which can occur after trauma or surgery.
- Scarred eardrum: A curve that can vary in shape, but indicates altered mobility due to scarring or adhesions on the eardrum.
- Fluid in the middle ear: Similar to the type “B” curve, indicating fluid in the middle ear that’s preventing normal eardrum mobility.
- Perforated eardrum: No proper curve is obtained, since pressure passes freely through the perforation, which can be mistaken for a type “B” curve.
By including these images and descriptions in the article, patients can get a visual understanding of what their tympanometry results mean. The aim of this article is to help patients learn how to read a tympanogram and understand the basics of their hearing health.
Tympanometry doesn’t just provide valuable information about the presence of middle ear abnormalities — it’s also crucial for monitoring and assessing how effective treatments are. For example, in patients treated for otitis media with effusion, tympanometry can help determine whether the fluid behind the eardrum has cleared after treatment. It’s also especially useful in paediatric populations, where other hearing tests can be difficult to carry out due to a child’s limited cooperation or understanding.
What’s more, tympanometry can play an important role in the early detection of disorders that could cause hearing loss if left untreated. In many cases, such as otosclerosis or Eustachian tube dysfunction, symptoms may not be obvious to the patient until the condition has progressed. Tympanometry offers a quick, non-invasive way to identify potential problems before they can cause more serious complications.
In a clinical setting, tympanometry results can help doctors make informed decisions about whether to refer patients to specialists, such as ENT doctors, for a more thorough assessment or for surgical procedures, such as the placement of ventilation tubes (grommets).
In short, tympanometry is an indispensable tool in audiological medicine that plays a vital role in diagnosing, managing and preventing a range of hearing conditions.
At the Juan Llorens hearing centre, tympanometry is a test we offer alongside pure-tone and speech audiometry, to give patients a complete assessment of their hearing health.
If you haven’t yet had your ears checked, we’d be delighted to see you, help you, and offer our advice.
