Tympanometry is a test to evaluate the functioning of the middle ear and the tympanic membrane. The test involves inserting a device into the outer ear to achieve a tight seal. Then the specialist causes a change in air pressure inside the atrial cavity to check the mobility of the eardrum and to see how the ear reacts to sound and pressure changes. During the test, the patient can hear very loud sound and may notice discomfort because of the probe. The results are plotted on a graph called a tympanogram. This technique is used to detect alterations in the middle ear, tympanic perforation, infectious otitis, tumours, bone diseases affecting the middle ear and birth defects, among others.