Tympanometry (Impedance Test): What It Checks in Your Middle Ear

Tympanometry, also called an impedance or immittance test, checks how well your middle ear is working. A soft rubber tip sits gently in your ear canal, changes the air pressure slightly, and plays a low tone while a machine measures how freely your eardrum moves. From this it can tell whether there is fluid behind the eardrum, whether the pressure inside is normal, and whether the eardrum and the tiny middle-ear bones are responding as they should. It is quick, painless, and usually done alongside pure tone audiometry. The one thing to remember is that it checks middle-ear function, not your hearing levels themselves.

What tympanometry actually measures

Your middle ear is the small air-filled space just behind the eardrum. It holds three tiny bones, the ossicles, that pass sound vibrations from the eardrum inward, and it connects to the back of your nose through the eustachian tube, which keeps the pressure balanced. For sound to travel efficiently, the eardrum needs to move freely and the pressure on both sides needs to be roughly equal. Tympanometry measures exactly this. By changing the air pressure in your ear canal and watching how the eardrum responds, the test shows whether that whole system is moving normally or whether something is holding it back.

The result is drawn as a simple graph called a tympanogram. The shape of the curve, where its peak sits, and how tall it is together tell your audiologist a clear story about the health of your middle ear.

What happens during the test

Nothing about the test is uncomfortable, and it usually takes only a minute or two per ear. You sit still, stay quiet, and let the machine do the work.

• Your audiologist looks into your ear first to check the canal is clear of wax.
• A soft rubber-tipped probe is placed snugly in the opening of your ear canal to make a gentle seal.
• The probe changes the air pressure slightly, so you may feel a light fullness, similar to a small altitude change.
• At the same time it plays a low humming tone and measures how much of that sound the eardrum reflects back.
• The machine plots the tympanogram automatically, and the probe is removed.

There are no needles, no loud sounds, and nothing that hurts. Children usually manage it well as long as they can sit calmly for a short while, which is part of why it is such a useful test for little ones.

It checks the middle ear, not your hearing

This is the part people most often misunderstand. Tympanometry does not tell you how well you hear. It does not measure the softest sounds you can detect or map your hearing across different pitches. That job belongs to pure tone audiometry, where you respond to beeps through headphones and the results are plotted on an audiogram. Tympanometry sits alongside that test as a partner, not a replacement. Where the audiogram shows what you can hear, tympanometry helps explain why, especially when the loss looks like it is coming from a mechanical problem in the middle ear rather than the inner ear or nerve.

Understanding your tympanogram result

Audiologists group tympanograms into a few broad shapes. The exact numbers matter less to you than the pattern, so here is what each common type suggests in plain terms.

Type A, normal movement

A Type A trace shows a clear peak at around normal pressure, which means the eardrum is moving freely and the pressure behind it is balanced. This is the healthy, expected result. If your hearing test also looks clear, your middle ear is very likely doing its job well.

Type B, a flat trace

A Type B tympanogram is flat, with no real peak. It usually means the eardrum is not moving much, and the most common reason is fluid sitting in the middle ear, the situation often called glue ear or otitis media. A flat trace can also appear when there is a hole in the eardrum, known as a perforation, or simply when the probe tip is blocked by wax or resting against the canal wall. Your audiologist reads it together with the rest of the picture to know which of these it is.

Type C, negative pressure

A Type C trace has a peak, but it is shifted towards negative pressure. This suggests the pressure inside the middle ear is lower than normal, which points to the eustachian tube not ventilating the space well. It is common with colds, allergies, and eustachian tube dysfunction, and it often settles on its own, though persistent cases are worth following up.

Acoustic reflexes, a quick add-on

Many clinics also measure acoustic reflexes during the same session. A louder tone is played and the machine checks whether a tiny middle-ear muscle tightens automatically in response, which it should do when sound reaches a certain level. Whether this reflex is present, absent, or shows up at unusual levels adds another clue about how the middle ear and the hearing pathway are working. Like the rest of the test, it is painless and takes only moments.

When tympanometry is used

Your audiologist may recommend it in several situations, including:

• Suspected fluid or glue ear in children, where it is one of the most reliable ways to catch a problem a child may not be able to describe.
• Blocked, popping, or full-feeling ears that point to a eustachian tube problem.
• A known or suspected perforated eardrum, or checking an ear after an infection has settled.
• Explaining a hearing test that looks conductive, meaning sound is being blocked somewhere in the outer or middle ear.
• Following up ear infections that keep coming back.

It is also a natural companion to newborn and childhood checks. If you want to understand how hearing is screened early in life, our guide to newborn and infant hearing screening explains the process, and our overview of the types and causes of hearing loss puts middle-ear problems in the wider picture.

"Tympanometry does not tell us how well you hear. It tells us how well your middle ear is moving, and that often explains what the hearing test is showing."

Who performs the test and who treats the cause

At a full diagnostic centre, an RCI-registered audiologist performs the test and interprets the tympanogram as part of the wider hearing assessment. If the results point to an active infection or a problem that needs medical or surgical care, that treatment is handled by a doctor or ENT specialist. The two roles work together: the audiologist measures and explains what is happening, and the ENT treats the underlying cause where one needs treating. Remember too that hearing aids manage hearing loss, they do not cure it, so getting the middle-ear picture right first matters.

What to do next

If your ears feel full, keep popping, or a hearing test has thrown up a result you do not fully understand, a proper middle-ear check can bring real clarity. Book a free hearing test at Prudent Hearing Solutions and our audiologists will run the full battery, including tympanometry and acoustic reflexes, and explain your results in plain language. You can see everything we offer on our services page, and our team across Pune, Delhi, and Bengaluru, plus home visits, is happy to help. Call +91 9429690093, Monday to Saturday, 10am to 7pm, to book with Prudent Hearing Solutions.