ENT specialist
Tympanometry (middle ear test)
Tympanometry tests how your eardrum and middle ear are working. It is quick and painless, and shows fluid or pressure problems behind the eardrum.
What is tympanometry?
Tympanometry is a quick test that shows how your eardrum moves and how your middle ear is working. The full name of the test is impedance audiometry, and it combines two studies: tympanometry itself (the so-called Jerger curves) and the acoustic (stapedial) reflexes. In most cases we only do the tympanometry.
We place a small probe at the entrance of your ear canal, gently change the air pressure and play a sound. The machine measures how much sound bounces back from the eardrum and draws a curve that tells us whether the middle ear is working normally.
What is it for?
- Finding fluid behind the eardrum, known as otitis media with effusion or “glue ear”, which is common in children: Middle ear infection.
- Assessing the Eustachian tube, the channel that ventilates the middle ear, when you have a blocked-ear feeling or pressure: Eustachian tube dysfunction.
- Explaining a conductive hearing loss, together with Pure-tone audiometry.
- Clearing up doubts after otoscopy. Looking at the eardrum is sometimes not enough to tell whether there is fluid, and tympanometry confirms it.
When do we also measure the acoustic reflexes?
The stapedial reflex is an automatic contraction of a tiny muscle in the middle ear, the stapedius muscle, when we hear a loud sound. Measuring it gives us information about the middle ear, the facial nerve and the hearing pathway.
In our clinic we keep it for specific cases, such as facial palsy or suspected otosclerosis (stiffness of the tiny bones of the ear that causes hearing loss).
How should I prepare?
You do not need any preparation.
- Tell us if you have a cold, earache or discharge from the ear.
- If you have ear tubes (grommets) or know you have a perforated eardrum, tell us (see below).
- If there is a plug of earwax, it will need to be removed first.
- For children, it helps if they stay still and calm. Crying or talking during the test can change the curve.
What happens during the test?
- We look in your ear to check that the canal is clear.
- We place a rubber probe that seals the entrance of the canal.
- You will feel slight pressure, like going up in a plane, and hear a soft sound. Stay still: do not talk, swallow or move.
- A curve appears on the screen within seconds. We repeat it in the other ear.
- If we also test the acoustic reflexes, you will hear louder, brief beeps through the same probe while we record the response.
It takes about 5 minutes if we only do tympanometry and about 10 minutes if we add the reflexes.
Does it hurt? Are there any risks?
It does not hurt. You will only feel pressure in your ear, like in a lift or a plane, for a few seconds. The reflex sounds are loud but very brief. If you are very sensitive to sounds, tell us. There are no significant risks.
Results
The curve appears straight away. The most common types are:
| Curve | What it usually means |
|---|---|
| Type A (curve with a central peak) | The eardrum and middle ear move normally. |
| Type B (flat curve, no peak) | Usually means fluid behind the eardrum or an eardrum that hardly moves. |
| Type C (peak shifted towards negative pressure) | Negative pressure in the middle ear, typical of a poorly working Eustachian tube, for example during a cold. |
| Type A with a very low or very high peak | A stiffer (low peak) or looser (high peak) eardrum or chain of tiny bones. |
If we measure the reflexes and they are absent, it may be due to a problem in the middle ear, the facial nerve or the hearing pathway. That is why we always interpret them together with the other tests.
A single result is not a diagnosis: we assess it together with the examination and the hearing test.
When can it not be done?
It is not done if there is a perforated eardrum or ear tubes (grommets). In these situations the results are unreliable and do not change what we decide to do. If the canal is blocked by wax, it needs to be cleaned first.
Frequently asked questions
Are tympanometry and impedance audiometry the same thing? Almost. Impedance audiometry is the full name of the test and includes tympanometry (the Jerger curves) and the acoustic reflexes. When people say “tympanometry” they usually mean only the first part.
Does it hurt? No. You will only feel slight pressure in your ear for a few seconds.
How long does it take? About 5 minutes if it is tympanometry alone, and about 10 if the acoustic reflexes are added.
Is it the same as a hearing test? No. Pure-tone audiometry measures how well you hear. Tympanometry assesses how the eardrum and middle ear work. They complement each other.
Why have I not had the reflexes measured? Because we only do them when they add something, for example with facial palsy or suspected otosclerosis. In most cases the curve is enough.
Can children have it? Yes, as long as they stay still for a few seconds.
What if I have ear tubes or a perforated eardrum? The test is not done in that case, because it does not give reliable results or change the treatment. We will examine you in another way.
References
- Rosenfeld RM, Shin JJ, Schwartz SR, et al. Clinical Practice Guideline: Otitis Media with Effusion (Update). Otolaryngol Head Neck Surg. 2016;154(1 Suppl):S1-S41.
- Jerger J. Clinical experience with impedance audiometry. Arch Otolaryngol. 1970;92(4):311-24.
- Azevedo C, Firmino Machado J, Fontes Lima A, et al. Value of simple otoscopy in diagnosing otitis media with effusion in children. Acta Otorrinolaringol Esp (Engl Ed). 2022;74(3):175-81.
For general information only. It does not replace a medical consultation and cannot be used for diagnosis. In an emergency in Spain, call 112.