Hearing tests measure the health of your ears, including how well your ears transport sounds to your brain. Most important, hearing tests can determine if you have hearing loss and can help to identify the cause. Your doctors can then let you know what treatment options are right for you.
Who Performs Hearing Tests?
Your doctor can perform basics hearing tests, but for more advanced testing you may be referred to a specialist, such as an ear, nose and throat doctor (called an otolaryngologist) or an audiologist, someone certified in the field of hearing and hearing loss.
Detecting hearing problems in newborns is a team effort. The team may include an otolaryngologist, audiologist, pediatrician, neonatologist and nurses. In children, hearing tests may be provided in school by a licensed speech pathologist or at the pediatrician’s office.
Hearing Evaluation In Children
In the United States, hearing loss is the most common birth defect, affecting 3 out of every 1000 newborns. The National Institutes of Health, American Academy of Pediatrics, and other experts recommend that all newborns have their first hearing test before they leave the hospital. As of March 2002, 36 states and the District of Columbia have passed laws related to newborn hearing screening. Many of these states have programs in place to provide the necessary testing in hospitals and birthing centers; other states are working toward this goal.
Infants with significant hearing loss who get help (such as hearing aids or surgery) before 6 months of age develop much better language skills than those who do not. When infants are not screened for hearing loss at birth, this problem typically is not detected until age 2 or even later and often results in language and speech delays that may be permanent.
Newborns who do not pass an initial hearing test are usually given a second screening test. If they fail again, more formal follow-up testing by an audiologist and an ear, nose and throat doctor (otolaryngologist) should occur before 3 months of age.
Screenings For Children
Hearing loss also can develop in the months and years after birth. Children should be tested for possible hearing loss whenever parents or other caregivers have any concerns about decreased hearing. In addition, testing is done routinely for children at high risk of hearing loss. This includes children who have developmental delays, especially in speech; syndromes involving the head that are associated with hearing loss; or other risk factors such as a history of premature birth, bacterial meningitis or a family history of hearing loss.
Routine screenings are recommended as follows:
- When first starting school
- Every year from kindergarten through 3rd grade
- In 7th grade
- In 11th grade
- If the child enters any special education classes
- If the child repeats a grade
- When a child enters a new school system without evidence of having passed a previous hearing screening
Hearing Evaluation In Adults
Most visits to a medical office require filling out a registration form and a medical history. A medical (or case) history should include information about your health over the years, as well as that of your family. Typical questions about hearing and hearing health are as follows:
- Have you had any drainage from your ear(s) in the past 90 days?
- Have you experienced any pain in you ear(s) in the past 90 days?
- Do you have difficulty while talking on the telephone with one or both ears?
- Do you have difficulty hearing in noisy environments?
Once the registration and history forms are completed, the audiologist will review your information and explain what tests you will have during your visit. Based on your answers and examination of your ears, the doctor will order one or more tests to determine the extent of hearing impairment.
Types Of Hearing Tests
Different tests evaluate different parts of the hearing (auditory) system in different ways. The test used depends in large part on your age. The most common tests are:
You can’t hear otoacoustic emissions, but these sound echoes bounce around inside your ear and make hearing possible.
Sound signals enter your ear and hit the cochlea, the bony maze of the inner ear that looks like a snail shell. The cochlea contains nerve endings that pick up sound signals. These sounds then “echo” back into your middle ear, making hearing possible.
Although you can’t hear the echoes, a probe inserted into the outer ear can measure them. This test is very useful in checking whether a newborn or infant can hear because the person being tested does not have to respond to any questions. The test machinery does all the work.
Auditory Brainstem Response
This test doesn’t actually measure how well you hear, but rather how well sounds travel along your auditory pathways. The test measures brain-wave activity in response to sound. This allows the examiner to detect any damage in the cochlea, the auditory nerve or the auditory pathways in the stem of the brain.
Electrodes are placed on the head of the person being tested. Headphones or earpieces send out a series of clicks that trigger brain-wave activity. Because the person being tested does not have to answer any questions, this test is ideal for children.
Visual Reinforcement Audiometry
This test trains a child to look toward an object that makes a sound. When the child gives a correct response (turning his or her eyes or head toward the sound), he or she receives a reward (or a reinforcement), such as a flashing light or moving toy.
The test measures how well a child can hear tones of various frequency (pitch) and speech. Generally used for infants and children aged 6 months to 2 or 3 years, the test takes place inside a booth (with speakers) or with headphones. Headphones are preferable because they give ear-specific information. Hearing loss in one ear (unilateral hearing loss) can be missed when using speakers.
Conditioned Play Audiometry
This test trains a child (aged 2 to 5) to perform a task when a sound is heard. The task can be putting blocks in a box, rings on a cone or pegs in a hole. Once the child learns to respond to the sounds, the sounds are gradually decreased to measure the child’s true hearing ability.
Headphones give the best results because they provide ear-specific information. If a child refuses to wear headphones, the test can be conducted in a sound booth, but the results are not as accurate. If a child can’t learn to respond to the sounds, otoacoustic emissions or auditory brainstem response testing will be used.
Pure Tone Audiometry
This test detects the type and severity of hearing loss at specific frequencies and decibels. It can pick up differences in hearing loss in one ear compared with the other. The test is used in children and adults.
A person who can’t hear any frequency fails this test and will need additional testing.
This test evaluates the health of the outer and middle ear. All age groups use this test, although it is particularly useful in diagnosing middle ear infections, a common condition among children.
The test can detect fluid or infection in the air-filled cavity of the middle ear, problems with the eardrum (tympanic membrane), including holes, and any air pressure imbalance related to problems along the Eustachian tube, which is responsible for keeping the air pressure equal on each side of your eardrum.
A small probe that looks like an earplug is placed in your ear. A gentle stream of air is pumped into the ear canal. You will feel pressure changes and hear sounds as air pressure hits your eardrum and the vibrations are transmitted to the bones in the middle ear. Some of the sounds may be loud and could even startle you.
Speech Testing Or Speech Audiometry
The first part of the speech test measures how softly a word can be spoken for you to be able to repeat it back properly.
The second part of the speech test measures speech discrimination. This determines how well you can hear and repeat words back that are given at a comfortable listening level. Individuals who have normal hearing generally get 100 percent of the words correct. Hearing loss is associated with reduced sound discrimination. The greater the hearing loss, the worse the discrimination.