I was told that my three-year-old child had a flat eardrum from a school screening and that I needed to see a doctor. I cannot get in to see a doctor for a few weeks. Could you tell me what can cause a flat eardrum? My daughter does not complain of pain.

Tyrrell

Are you old enough to remember the movie Cool Hand Luke? The most memorable line from the movie belonged to actor Strother Martin: "What we have, here, is a failure to communicate." Unfortunately, without Strother Martin's thick Southern drawl, the line lacks punch.

So, instead, let me substitute Charlie Brown's famous howl: "ARRRGH!" Your three-year-old does NOT have a flat eardrum! She probably has a flat tympanogram, which is quite a different thing.

A tympanogram is a graph generated by a machine called a tympanometer. This machine measures the ability of the eardrum to reflect sound. In other words, it measures an echo. The eardrum is a mobile (flexible) membrane, and its ability to reflect sound is related to its mobility. The medical term for eardrum is "tympanic membrane," hence the machine is called a "tympanometer."

A normal tympanogram looks a bit like an upside-down V. The point of the V is centered over 0. Such a tympanogram indicates that the eardrum has a normal degree of mobility, and that the air pressure behind the eardrum is the same as the air pressure in the room. If the point of the V is shifted to the left of 0 (for example, it may be centered over -90), this indicates that the air pressure behind the eardrum is LESS than the air pressure in the room. This is a sign of eustachian-tube dysfunction.

A flat tympanogram indicates that very little sound is being reflected back to the tympanometer. This result can be due to a variety of things, some of them very trivial. For example, a wax-filled ear canal will block sound, leading to a flat tympanogram. Also, if the earplug on the tympanometer made a poor seal with your daughter's ear, an inexpensive tympanometer would not catch this error and would probably give a flat tympanogram.

Assuming your daughter does not have ear wax, and that the tympanometer was used correctly, what is the significance of a flat tympanogram? In this situation, a flat tympanogram usually means one of two things. Either your daughter has fluid behind her eardrums, or she has holes in her eardrums. If either situation is true, then consultation with a doctor is, indeed, a good idea. Even if it's just a wax problem, it would be an excellent idea for a doctor to clean your daughter's ears. Wax can cause a great deal of hearing loss, and it is an easily treatable problem.