Acoustic Immittance Measures/Tympanometry
Tympanometry is used to take measurements of our ears and is sensitive to middle-ear problems. It is a quick, painless test that can be completed on infants, children and adults. A soft tip connected to a probe that controls air pressure and a low tone is placed in the ear canal to make measurements. Subtle ear pressure is introduced into the ear, and a computer translates the readings from the ear canal into a graph called a tympanogram. Tympanometry measures the volume or amount of space from the tip of the probe to the eardrum (tympanum). In children, this helps determine if a surgically-placed tube in the eardrum is open or closed.
Also, tympanometry measures the status and health of the middle ear. The Eustachian tube runs from the throat to the middle ear. The purpose of the Eustachian tube is to equalize the pressure in your middle ear with the atmospheric pressure. For example, when you are on a plane and the pressure in the cabin changes, you may notice a “popping” sound. This is the sound of your Eustachian tube opening to equalize the pressure in your middle ear. Some individuals experience Eustachian tube dysfunction which can create positive or negative pressure in the middle ear and is measured and read on the tympanogram.
When there is abnormal movement of the eardrum as air pressure is put into the ear canal, there may be fluid behind the eardrum or a hole or rupture in the eardrum.
Acoustic Reflex Thresholds measure the stapedial muscle's response to higher intensity at specific frequencies involving the cochlea (organ of hearing), the auditory pathway within the brainstem and two of the 12 cranial nerves, the VIIth (facial) and VIIIth (auditory).