In tympanometry, air pressure is applied to the external ear canal, and the movement of the middle ear and eardrum is assessed. By measuring the movements in the middle ear and eardrum, it is possible to obtain information about the function of these structures. Measurements are taken using a probe placed in the ear. Tympanometry can be easily performed even on infants. The only requirement for the test is that the eardrum is not perforated.