To treat hearing loss, hearing health professionals need to know what’s causing it. When a doctor believes middle ear problems may be to blame, they will order a tympanometry test. This article will tell you all about tympanometry, including how and why it’s performed and common results.
What Is Tympanometry?
Tympanometry is a test used to diagnose disorders of the middle ear. It measures the eardrum’s movement and middle ear function. Though this test can be performed on adults and children, children are more prone to middle ear disorders. Tympanometry is non-invasive, quick, and painless.
Why Tympanometry is Performed
Tympanometry will be ordered if an ENT doctor suspects hearing loss with middle ear involvement. It’s also a part of a routine hearing test, but not a part of online hearing tests.
The test results will help your care team decide if you’re a suitable candidate for treatments like corrective surgery or hearing aids.
How the Eardrum Works
To grasp the importance of tympanometry, it helps to know a little about the eardrum’s role in hearing.
Also called the tympanic membrane, the eardrum is a thin piece of tissue that separates the middle ear from the ear canal and outer ear structures.
Sound waves cause the eardrum to vibrate, setting the tiny bones underneath into motion. This movement, in turn, stimulates the fluid inside the inner ear. The tiny sensory hair cells that line the cochlear capture the vibrations and convert them into electrical signals that are sent to the brain via the auditory nerve.
You can also measure the range of sound waves you can hear with a sound frequency test.
If the eardrum isn’t working, sound waves won’t be transmitted efficiently to the inner ear, leading to hearing loss.
Common Middle Ear Problems
Abnormal eardrum movement might be due to one of the following causes:
- Middle ear infection (otitis media)
- Middle ear fluid buildup
- Holes or tears
How Is Tympanometry Done
Tympanometry is a two-minute test typically performed by an audiologist.
Tympanometry tests use a device called a tympanometer, consisting of a hand-held probe or a flexible rubber tip that is inserted in the ear canal.
The probe has three parts: loudspeaker, pump, and microphone. The loudspeaker plays loud tones, the pump alters the pressure, and the microphone picks up the sounds reflected off the eardrum.
Tympanometers also have a manometer to monitor the air pressure change. The instrument displays the output on a graph called the tympanogram.
Next, the ear specialist will place the probe-end of the tympanometer into your ear canal. You will be asked to sit still and not move, speak or swallow during the entire test to get accurate results.
When the test begins, you may hear different tones and feel the air pressure changing in your ear. The tympanometer will alter the pressure in the middle ear using the pump and emit tones through the speaker. The eardrum will absorb some of the tones, while the rest will be reflected back through the ear canal.
The tones reflected off the eardrum will be analyzed to determine the ear canal volume, compliance of the eardrum, and the pressure in your ear. The output will be displayed on a graph called a tympanogram.
What Happens After Tympanometry Testing?
After tympanometry testing, the hearing professional will interpret the tympanogram. If the audiologist sees abnormal results, they will most likely refer you to an ENT for wax removal, ear infection treatment, surgery, or another medical intervention.
Tympanograms are mainly classified into three based on the shape of the graph: Type A, Type B, and Type C.
- Type A: All metrics—ear pressure, eardrum compliance, and ear canal volume—are within the normal limits. A Type A tympanogram suggests normal middle ear function.
- Type B: The tympanogram is flat, which likely means fluid in the middle ear space or an eardrum perforation.
- Type C: This tympanogram signifies negative middle ear pressure due to eustachian tube dysfunction. The eustachian tube connects the ear to the back of the throat.
An abnormal tympanogram may indicate one of the following conditions.
- Middle ear effusion
- Eardrum perforation
- Stiffness in the small bones of the middle ear
- Earwax impaction or other obstruction
- Scarred eardrum
Pure Tone Audiometry vs. Tympanometry
Audiometry measures an individual’s hearing thresholds to determine the type and severity of hearing loss, whereas a tympanometry test attempts to discover the cause.
The major difference is that pure tone audiometry can be used to diagnose hearing loss whereas tympanometry cannot.
To find out how old is your hearing, you can read more about the eChalk test in our guide.
A tympanometry test measures how the eardrum moves. It’s useful for ruling out disorders in the middle ear system. Tympanometry is a necessary step for determining the best course of treatment.
Before an audiologist prescribes hearing aids, they need to eliminate middle ear causes, which can often be treated medically. For example, an ENT can usually treat chronic fluid buildup, the most common cause of middle ear dysfunction.