LAB TEST
Audiometry
An audiometry exam 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). The INTENSITY of sound is measured in decibels (dB): A whisper is about 20 dB. Loud music (some concerts) is around 80 to 120 dB. A jet engine is about 140 to 180 dB. Sounds greater than 85 dB can cause hearing loss after a few hours. Louder sounds can cause immediate pain, and hearing loss can develop in a very short time. The TONE of sound is measured in cycles per second (cps) or Hertz (Hz): Low bass tones range around 50 to 60 Hz. Shrill, high-pitched tones range around 10,000 Hz or higher. The normal range of human hearing is about 20 to 20,000 Hz. Some animals can hear up to 50,000 Hz. Human speech is usually 500 to 3,000 Hz.
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…
How to Prepare for the Test
No special steps are needed.
How the Test will Feel
There is no discomfort. The length of time varies. An initial screening may take about 5 to 10 minutes. Detailed audiometry may take about 1 hour.
Why the Test is Performed
This test can detect hearing loss at an early stage. It may also be used when you have hearing problems from any cause.
Normal Results
Normal results include: The ability to hear a whisper, normal speech, and a ticking watch is normal. The ability to hear a tuning fork through air and bone is normal. In detailed audiometry, hearing is normal if you can hear tones from 250 to 8,000 Hz at 25 dB or lower.
What Abnormal Results Mean
There are many kinds and degrees of hearing loss. In some types, you only lose the ability to hear high or low tones, or you lose only air or bone conduction. The inability to hear pure tones below 25 dB indicates some hearing loss. The amount and type of hearing loss may give clues to the cause, and chances of…
Risks
There is no risk.
Considerations
Other tests may be used to determine how well the inner ear and brain pathways are working. One of these is otoacoustic emission testing (OAE) that detects sounds given off by the inner ear when responding to sound. This test is often done as part of a newborn screening. A head MRI may be done to help diagnose hearing…
References
Amundsen GA. Audiometry. In: Fowler GC, ed. Pfenninger and Fowler's Procedures for Primary Care . 4th ed. Philadelphia, PA: Elsevier; 2020:chap 59. Kileny PR, Zwolan TA, Slager HK. Diagnostic audiology and electrophysiologic assessment of hearing. In: Flint PW, Francis HW, Haughey BH, et al, eds. Cummings…
This is a summary. Read the full article at www.ucsfbenioffchildrens.org (reviewed 02/05/2024).
This page is general information and is not medical advice. It does not replace a registered doctor, and it is not a prescription or a recommendation to use any medicine or test. Prices are listed prices and may change. Always follow the advice of your doctor or pharmacist.