Impedance Test
The Impedance Test, also known as Impedance Audiometry or Tympanometry, is a diagnostic procedure used to assess the health and function of the middle ear and the mobility of the eardrum (tympanic membrane) and the tiny bones (ossicles) in the middle ear. This test provides valuable information about conditions such as middle ear infections, Eustachian tube dysfunction, and other problems that can affect hearing.
Here's how the Impedance Test is typically conducted:
The patient is seated comfortably. A small probe is gently placed into the ear canal. The probe contains a speaker that emits a pure tone sound and a microphone that measures the sound that reflects back from the ear.
The probe changes the air pressure in the ear canal while playing a pure tone sound. As the air pressure changes, the eardrum’s mobility is measured, and the amount of sound reflected back is recorded.
The audiologist analyzes the tympanogram to assess the health of the middle ear. The tympanogram’s shape and peak value provide information about the eardrum’s mobility, the pressure in the middle ear, and the presence of any abnormalities or issues.
Based on the tympanogram’s results, the audiologist classifies the findings and discusses the implications with the patient. Common classifications include Type A (normal middle ear function), Type B (indicative of middle ear fluid or other issues), and Type C (negative pressure in the middle ear).
The Impedance Test is particularly useful for identifying conditions such as
Middle ear infections or inflammation that can cause fluid buildup and affect hearing.
A problem with the tube that connects the middle ear to the back of the throat, which can impact pressure regulation in the middle ear.
A condition where the ossicles become less mobile due to abnormal bone growth, leading to conductive hearing loss.