Tympanometry tests the movement of the eardrum, ruling out the presence of an ear infection or other middle ear problem.

A tip of a handheld tool is placed into the ear canal. The tool changes the air pressure inside the ear and produces a clear tone. Then the tool measures how the eardrum responds to the pressure and the sound.

The results of this test are used to help figure out what is going on in the ear.

Normally the eardrum moves easily when pressure in the ear canal is changed. Most of the time, if the test is normal, there is no fluid behind the eardrum. When the eustachian tube, which connects the back of the nose and throat with the middle ear, is not working well, the eardrum does not move as it should. 

This test is very simple and quick and all it requires you to do is to sit quietly for 30 seconds or so whilst the measurement is taken.