Consisting of a group of nerve fibers, the auditory nerve is one of the key nerves that can affect hearing.
In order to pinpoint a specific issue with this nerve or other parts of the nervous system responsible for sending hearing-related information to the brain, an audiologist may perform an auditory brain stem response (ABR) evaluation.
- It’s a test that measure reactions of different parts of the nervous system related to hearing functions.
- It can also be done to test hearing thresholds to determine what type of treatment to recommend to correct hearing problems.
What Is an ABR Test?
Painless and noninvasive, an ABR test involves the use of a computer that measures the way hearing nerves react to different sounds. Electrodes are placed on the head and around the ears to record nerve responses. An audiologist looks for specific markers as the intensity level of the sound delivered changes. Abnormalities can be identified by looking at the printout from the test.
Who May Need This Test?
An auditory brain stem response evaluation may be performed if a newborn fails the hearing screening test that’s typically given shortly after birth. It may also be performed on older children with suspected hearing loss that hasn’t been detected sufficiently with other tests. An ABR test may also be done to confirm the results of previous tests.
What Can Be Done to Prepare for the Test?
Parents of babies being tested are sometimes advised to bring them to the test location hungry and tired. This way, they can be fed just before testing so they’ll likely sleep through the ABR test process. If older children aren’t able to cooperate during their initial visit for an ABR test, another test may be scheduled with sedation.
An audiologist will determine if there are any other special instructions that apply.
How Is an ABR Test Performed?
The test is performed when the patient is lying down in a sound booth. Because patients need to remain still and quiet, sedation is often used for younger children and infants unable to do so. Children older than 7 are instructed to remain still on a bed or in a reclining chair. If sedation is needed, an anesthesiologist handles the necessary preparations prior to the test.
During the test, electrodes are attached and earphones are placed on the patient’s ears. Sounds are then transmitted through the earphones at different sound levels and ranges. The electrodes collect the information that’s used to produce a printout of nerve responses to various sound levels. Results are usually compared with results from other hearing tests that were conducted.
It typically takes about 1-2 hours to complete an auditory brain stem response evaluation. Audiologists can usually make adjustments to accommodate children with special needs or health issues.