The audiologist may conduct some or all of the following basic tests
Pure Tone tests: The air conduction test is the most general hearing test as it evaluates the entire mechanism: the outer, middle and inner ear as well as the hearing nerve. Soft tones are played through a set of headphones to determine the hearing threshold (the softest sound one can hear at least 50% of the time) for different pitches. If there ishearing loss, the bone conduction test can help determine whether the problem is in the outer, middle or inner ear. A small vibrator is placed on the skull bone directly behind the ear. When sound is transmitted through this device, it bypasses the outer and middle ear and delivers the sound vibrations directly to the inner ear. If the hearing improves during this procedure, then the audiologist knows there is a problem involving the conduction of sound through the outer or middle ear. (It can also be a combination of both conductive hearing lossand sensori- neural loss.) If the hearing loss is the same after this test, then the problem most likely lies in the inner ear.Once the results of the tone tests are in, the audiologist can prepare an audiogram, a picture of our hearing.
Tympanometry tests the flexibility of the ear drum. The eardrum must be extremely pliable so it can respond to the softest impulses. But sometimes, over time, the eardrum stiffens and it takes a stronger, more forceful sound wave to make it move. The audiologist determines its flexibility by taking some air out of the air canal (painless) and pumping some back in. As he does this, he measures the minute movement of the eardrum.
Word tests shed light on how well one understands normal conversation. There is a difference between being able to hear words and being able to understand them. The speech reception threshold test determines the softest level at which an individual can hear words. The speech recognition test determines how well the individual can understand words spoken at normal volume. The words include all the common phonemes (basic sounds) of normal conversation.