A hearing (audiometric) test is part of an ear
examination that evaluates a person's ability to hear by measuring the ability
of sound to reach the brain.
The sounds we hear start as
vibrations of air, fluid, and solid materials in our environment. The
vibrations produce sound waves, which vibrate at a certain speed (frequency)
and have a certain height (amplitude). The vibration speed of a sound wave
determines how high or low a sound is (pitch). The height of the sound wave
determines how loud the sound is (volume).
Hearing happens when
these sound waves travel through the ear and are turned into nerve impulses.
These nerve impulses are sent to the brain, which "hears" them.
- Sound waves enter the
ear through the ear canal (external ear) and strike
the eardrum (tympanic membrane), which separates the ear canal and the middle
- The eardrum vibrates, and the vibrations move to the bones of
the middle ear. In response, the bones of the middle ear vibrate, magnifying
the sound and sending it to the inner ear.
- The fluid-filled,
curved space of the inner ear, sometimes called the labyrinth, contains the
main sensory organ of hearing, the cochlea. Sound vibrations cause the fluid in
the inner ear to move, which bends tiny hair cells (cilia) in the cochlea. The
movement of the hair cells creates nerve impulses, which travel along the
cochlear (auditory, or eighth cranial) nerve to the brain and are interpreted
Hearing tests help determine what kind of
hearing loss you have by measuring your ability to
hear sounds that reach the inner ear through the ear canal (air-conducted
sounds) and sounds transmitted through the skull (bone-conducted sounds).
Most hearing tests ask you to respond to a series of tones or
words. But there are some hearing tests that do not require a response.
Why It Is Done
Hearing tests may be done:
- To screen babies and young children for hearing
problems that might interfere with their ability to learn, speak, or understand
United States Preventive Services Task Force
recommends that all newborns be screened for hearing loss.1 All 50 states require newborn hearing tests for all babies
born in hospitals. Also, many health organizations and doctors' groups
recommend routine screening. Talk to your doctor about whether your child has
been or should be tested.
- To screen children and teens for
hearing loss. Hearing should be checked by a doctor at each
well-child visit. In children, normal hearing is
important for proper language development. Some speech, behavior, and learning
problems in children can be related to problems with hearing. For this reason,
many schools routinely provide hearing tests when children first begin school.
The American Academy of Pediatrics recommends a formal hearing test at ages 4,
5, 6, 8, and 10 years. 2
- To evaluate possible
hearing loss in anyone who has noticed a persistent hearing problem in one or
both ears or has had difficulty understanding words in
- To screen for hearing problems in older adults.
Hearing loss in older adults is often mistaken for diminished mental capacity
(for instance, if the person does not seem to listen or respond to
- To screen for hearing loss in people who are
repeatedly exposed to loud noises or who are taking certain antibiotics, such
- To find out the type and amount of hearing loss
(conductive, sensorineural, or both). In conductive hearing loss, the movement
of sound (conduction) is blocked or does not pass into the inner ear. In
sensorineural hearing loss, sound reaches the inner ear, but a problem in the
nerves of the ear or, in rare cases, the brain itself prevents proper