Diseases & Conditions

Audiogram - Hearing Test


Overview & Description

A hearing test determines how well a person can hear different sounds.

How is the test performed?

Sounds are transmitted by sound waves that travel through the air and through bone. A hearing test usually determines how well a person hears sounds that are presented to the ear and to the skull bones.

Testing for sounds that travel through the air is done with a person wearing earphones over his or her ears. Pure tones of various frequencies are presented to one ear at a time at controlled volumes. The person being tested is asked to indicate when he or she first hears the sound. The softest sounds that the person can detect are recorded for each frequency. The results are put on a graph and compared to a normal hearing graph, or audiogram.

To test for sounds that travel through the bone, tuning forks of different frequencies are tapped and held against a person's skull. The person being tested is asked to indicate which sounds he or she can detect.


Preparation & Expectations

What is involved in preparation for the test?

No special preparation is required for a hearing test.


Results and Values

What do the test results mean?

The loudness of sound is measured in units called decibels (dB). A soft sound, such as normal speech, ranges from 5 to 10 dB. A loud sound, such as a jet plane taking off nearby, is about 180 dB. Loud music, such as rock concerts, can reach 80 to 120 dB. Sounds louder than 85 dB can cause hearing loss.

A person with normal hearing can detect low tones (frequencies of 64 cps, or cycles per second) at 1 to 2 dB and high tones (around 11,500 cps) at 10 dB. Most tones in between these extremes can be heard at less than 10 dB. If a person cannot detect pure tones below 10 dB, some hearing loss may be present.

Conditions that may lead to hearing loss are:

  • acoustic neuroma, which is a noncancerous growth of the acoustic nerve in the ear canal
  • acoustic trauma, which is hearing loss caused by loud noise that occurs slowly over time
  • age-related hearing loss, which is hearing loss that occurs as a natural result of aging
  • Alport's syndrome, which is a genetic disorder that consists of nerve-related deafness and kidney problems
  • labyrinthitis, or inflammation of the inner ear canals
  • Meniere's disease, which is a disease of the inner ear that causes dizziness, ringing in the ear, and nerve-related deafness
  • occupational hearing loss, which is hearing loss that occurs as a result of noise or other factors on the job
  • otosclerosis, which is abnormal bone formation in the inner ear
  • ruptured or perforated eardrum

  • Attribution

    Author:David T. Moran, MD
    Date Written:
    Editor:Crist, Gayle P., MS, BA
    Edit Date:07/31/01
    Reviewer:Eileen McLaughlin, RN, BSN
    Date Reviewed:05/29/01