Impedance audiometry is primarily used to test the condition of the middle ear along with the mobility of the eardrum. This audiometry test is also known as Tympanometry and is considered as one of the most accurate methods for testing the middle ear.
When the impedance audiometry test procedure starts, the patient is requested to sit still and avoid swallowing because these activities can hamper the test results. This test is completely painless and takes up to 15-20 mins wherein the audiologist thoroughly examines the ear canal with an otoscope. While undertaking this test, a probe with a soft plastic tip is used which is inserted and then fixed in the ear canal so that an airtight seal can be attained. Furthermore, a tone is stimulated in the ear canal wherein the air pressure varies from +200 to -400 decapascal and alongside the patient starts feeling the pressure variation. The results can be seen in the form of a graph which is plotted by the immittance audiometry machine. Various pathologies like fluid in the ear, reduced middle ear mobility and dysfunction of eustachian tube can be diagnosed with this test.