An audiometry tests your ability to hear sounds. Sounds vary, based on their loudness (intensity) and the speed of sound wave vibrations (tone). Hearing occurs when sound waves stimulate the nerves of the inner ear. The sound then travels along nerve pathways to the brain. Sound waves can travel to the inner ear through the ear canal, eardrum, and bones of the middle ear (air conduction). They can also pass through the bones around and behind the ear (bone conduction).
How the Test is Performed?
Your health care provider may test your hearing with simple tests that can be done in the office. These may include completing a questionnaire and listening to whispered voices, tuning forks, or tones from an ear examination scope.
A specialized tuning fork test can help determine the type of hearing loss. The tuning fork is tapped and held in the air on each side of the head to test the ability to hear by air conduction. It is tapped and placed against the bone behind each ear (mastoid bone) to test bone conduction. A formal hearing testing can give a more exact measure of hearing. Several tests may be done:
- Pure tone testing (audiogram) -- For this test, you wear earphones attached to the audiometer. Pure tones are delivered to one ear at a time. You are asked to signal when you hear a sound. The minimum volume required to hear each tone is graphed. A device called a bone oscillator is placed against the mastoid bone to test bone conduction.
- Speech audiometry -- This tests your ability to detect and repeat spoken words at different volumes heard through a head set.
- Immittance audiometry -- This test measures the function of the ear drum and the flow of sound through the middle ear. A probe is inserted into the ear and air is pumped through it to change the pressure within the ear as tones are produced. A microphone monitors how well sound is conducted within the ear under different pressures.
