There are several types of hearing tests, each designed to examine a different function of the ear. The tests prescribed to you will depend on your hearing loss symptoms and your situation. Their results will allow a hearing professional to correctly diagnose and treat your hearing problem. In this article, we tell you everything you need to know about the Auditory Brainstem Response (ABR) test.
What is the Auditory Brainstem Response test?
The Auditory Brainstem Response (ABR) test evaluates the function of the inner ear and the brain's nerve pathways by recording your auditory nerve's response to different sounds. In other words, it determines your ability to hear. An ABR test is typically prescribed when a person has already undergone other conventional hearing tests without conclusive evidence of hearing loss. It is also prescribed to babies who fail their initial hearing screening at the maternity ward. The ABR is completely painless and non-invasive, but it can only be performed if the patient remains perfectly still, is asleep, or is under anesthesia. This hearing test is most often performed on newborns and young children because it is specifically designed for those who cannot undergo conventional hearing screening.
How is an ABR test performed?
The hearing professional places headphones on the patient and places small electrodes near the ears and on the forehead, connected to a computer. A brief click or tone is played through the headphones, and the brainstem's response to this sound is measured by the electrodes. The data collected by the electrodes is recorded on the computer.
How do I prepare for an ABR test?
If you are bringing your baby (0 to 6 months old) for an ABR test, it is best for them to be hungry and tired as the appointment approaches. This is a difficult thing for any parent to do, but it is important: once there, your baby will quickly fall asleep after being fed. The hearing professional will then perform the test while the baby sleeps in your arms or in a bassinet.
Children up to 7 years old generally require anesthesia for the ABR test. Your hearing professional should provide you with specific instructions to follow at home before the appointment. Generally: no food and only clear liquids until two hours before the appointment, then no food or liquids for the two hours immediately preceding it. Beyond 7 years old, most children manage to stay still enough to take the test while awake, but anesthesia can be administered if necessary.
What do the results of an Auditory Brainstem Response test mean?
The faintest tone perceived during the test corresponds to the hearing threshold for that frequency, i.e., that pitch. The results are printed from the computer and analyzed by your hearing professional. Depending on the intensity required for the patient to hear the sound, and whether or not they heard it, the hearing professional will know if a hearing problem is present. Other examinations may then be prescribed to the patient to determine the origin of the hearing disorder and to establish a precise diagnosis as well as a treatment plan adapted to their hearing situation.
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