- Tympanometry is not a hearing test but a procedure that can show how well the eardrum moves when a soft sound and air pressure are introduced in the ear canal. It’s helpful in identifying middle ear problems, such as fluid collecting behind the eardrum.
- A tympanogram is a graphic representation of tympanometry. A “flat” line on a tympanogram may indicate that the eardrum is not mobile, while a “peaked” pattern often indicates normal function. A visual ear examination should be performed with tympanometry.
- It is performed to determine the status of the tympanic membrane and middle ear via tympanometry. The secondary purpose of this test is to evaluate acoustic reflex pathways, which include cranial nerves (CN) VII and VIII and the auditory brainstem. This test does not directly assess auditory sensitivity, although results are interpreted in conjunction with other threshold measures.
It measures sound reflection from the tympanic membrane, while the operator varies air pressure in the ear canal. Tympanometry aids assessment of the outer and middle ear system, including the Eustachian tube.
Acoustic Reflex Threshold
It is a middle ear measurement of stapedius muscle response to higher intensity and adequate duration sounds for individual frequencies.
Acoustic reflex decay test
It assesses the integrity of CN VIII. A contralateral continuous tone is presented for 10 seconds at a stimulus level 10 dB above the acoustic reflex threshold for that stimulus frequency in that ear.