Pure-tone Audiometry

None.

To diagnose hearing problems that result from such conditions as acoustic trauma, sudden hearing loss, or rock-and-roll deafness.

Your ability to hear tones at different volumes and pitches is measured when the sound is transmitted through bone and through air. A comparison between these two types of conduction can help determine which part of the hearing mechanism is responsible for the loss.

Your ears are checked to be sure wax is not blocking the ear canal. If so, you will be sent to a doctor for removal of the wax.

• If the test is being performed in a hospital audiometry department, you enter a special soundproof metal room.
• You don headphones and are instructed to raise your hand when you hear a tone.
• Tones (steady or beeping) are played at six different pitches, representing the range of human hearing.
• Each time you raise your hand, the volume is dropped 10 decibels (dB) until you can no longer hear it. The test is repeated in the other ear.
• You remove the headphones and put on a headband with a small plastic rectangle that fits behind your ear and conducts sound to your bone. The tones are repeated.
• If either ear tests poorly with earphones but normally with the bone-conduction piece, crossover (the good ear "helping out" the poor ear) is suspected. The good ear will then be covered with a headphone, background masking noise played, and the test resumed.
• To test your ability to discern speech, you will put on the earphones again and listen to and repeat 25 common words.

You are free to leave and resume normal activities.

Ambient sound when the test is not performed in a soundproof room, as is common in screening tests.

The results of audiograms are most often displayed in grid form, showing the amount of hearing loss expressed in decibels at different sound frequencies (also called hertz or Hz). High frequencies correspond to high tones, and low frequencies to low tones. Most audiograms range from around 250 to 4,000 Hz, and normal hearing is considered 0 dB to 20 dB. The failure to pick out any tone of 20 dB or louder indicates a degree of hearing loss. On the speech test, a score of 85% or better is deemed normal.

It's quick, painless, and accurate.

None.

• If responses are normal, no additional testing or treatment is needed.
• If the bone test indicates a conductive hearing loss, a tympanogram may be recommended.
• An unexplained difference between the two ears in the tone test or the speech segment may warrant a test, called an auditory brain stem response (ABR) or a brain stem evoked response, to look for an acoustic tumor.