Hearing Tests with a Tuning Fork
Hearing Tests with a Tuning Fork
Definition
A tuning fork is a metal instrument with a handle and two prongs or tines. Tuning forks, made of steel, aluminum, or magnesium-alloy will vibrate at a set frequency to produce a musical tone when struck. The vibrations produced can be used to assess a person's ability to hear various sound frequencies.
Purpose
A vibrating tuning fork held next to the ear or placed against the skull will stimulate the inner ear to vibrate, and can help determine if there is hearing loss.
Precautions
No special precautions are necessary when tuning forks are used to conduct a hearing test.
Description
Two types of hearing tests with tuning forks are typically conducted. In the Rinne test, the vibrating tuning fork is held against the skull, usually on the bone behind the ear (mastoid process) to cause vibrations through the bones of the skull and inner ear. It is also held next to, but not touching, the ear, to cause vibrations in the air next to the ear. The patient is asked to determine which sound is louder, the sound heard through the bone or through the air. A second hearing test using a tuning fork is the Weber test. For this test, the stem or handle of the vibrating tuning fork is placed at various points along the midline of the skull and face. The patient is then asked to identify which ear hears the sound created by the vibrations. Tuning forks of different sizes produce different frequencies of vibrations and can be used to establish the range of hearing for an individual patient.
Preparation
No special preparation is required for a hearing test with tuning forks.
Aftercare
No special aftercare is required. If hearing loss is revealed during testing with tuning forks, the patient may require further testing to determine the extent of the hearing loss.
Risks
There are no risks associated with the use of tuning forks to screen for hearing loss.
Normal results
With the Rinne test, a person will hear the tone of the vibration longer and louder when the tuning fork is held next to the ear, rather than when it is held against the mastoid bone. For the Weber test, the tone produced when the tuning fork is placed along the center of the skull, or face, sounds about the same volume in each ear.
Abnormal results
The Rinne test detects a hearing loss when a patient hears a louder and longer tone when the vibrating tuning fork is held against the mastoid bone than when it is held next to the ear. The volume of sound vibrations conducted through parts of the skull and face in the Weber test can indicate which ear may have a hearing loss.
Resources
ORGANIZATIONS
American Academy of Otolaryngology-Head and Neck Surgery, Inc. One Prince St., Alexandria VA 22314-3357. (703) 836-4444. 〈http://www.entnet.org〉.
Ear Foundation. 1817 Patterson St., Nashville, TN 37203. (800) 545-4327. 〈http://www.earfoundation.org〉.
KEY TERMS
Mastoid process— The protrusions of bone behind the ears at the base of the skull.
Rinne test— A hearing test using a vibrating tuning fork which is held near the ear and held at the back of the skull.
Weber test— A hearing test using a vibrating tuning fork which is held at various points along the midline of the skull and face.