There are many different ways to test a child’s hearing, such as letting them sleep! Since infants aren’t able to raise their hands when they hear the beeps, pediatric audiologists use a test called an Auditory Brainstem Response (ABR) to assess your child’s hearing while they sleep.
What Is An ABR?
The Auditory Brainstem Response (ABR) test is a specialized test designed to evaluate the auditory system, beginning from the outer ear and up to the level of the brainstem. Although the ABR test is a helpful tool in determining your child’s ability to hear, it is not a hearing evaluation, but rather an objective measure of the auditory system’s response to sound. The test uses a special computer to measure the way your child’s hearing nerve responds to different sounds, such as a click or various pitches of tone bursts. Four small stickers, known as electrodes, will be placed on your child’s head and behind their ears and then connected to a computer. As sounds are made through tiny earphones, the electrodes measure how your child’s hearing nerves respond to them. An ABR test is safe and painless.
ABRs are recommended when a baby fails their newborn hearing screening test given at the hospital shortly after birth to confirm or rule out hearing loss. Generally, ABRs are also used with children who are unable to complete conventional hearing tests in a sound booth because the child might be too young, have limited attention, are unable to understand testing procedures, or have medical involvement or developmental delays that makes sitting still and responding to sounds difficult.
How Is The ABR Completed?
Our pediatric audiologists will first need to clean part of your child’s forehead and behind their ears. This will be done using either an exfoliating paste or a small exfoliating pad. Small electrode stickers will be placed on these clean areas. Designed to pick up on the auditory system’s response to sounds, the electrodes will cause no pain or discomfort to your child. These electrodes can also pick up on muscle movement, which is why your child must be asleep to complete this test. If your child is awake and moving during the test, the results will not be reliable.
Your child will also wear headphones in their ears for the test duration. These headphones act as small speakers that introduce sound into the ear canal and travel through the hearing system. Through the headphones, your child will hear a variety of sounds; from low-pitched (500 Hz tone bursts) to high-pitched (4000 Hz tone bursts), these tone bursts will also be used to estimate your child’s hearing sensitivity or the softest level of the auditory system’s response to sounds. Click stimulus is also used to estimate hearing in the 1000-4000 Hz range and, at a higher intensity, can rule out a rare form of hearing loss.
If your child has hearing loss, a bone conduction ABR will also be completed. For this test, a small vibrating oscillator, called a bone conductor, will be placed behind your child’s ear. The bone conductor uses tiny vibrations to vibrate the skull and send sound waves directly to the hearing organ called the cochlea. Bone conduction ABR is used to determine the specific type of hearing loss your child might have, such as sensorineural or conductive hearing loss.
How Are The Results Of An ABR Collected?
During the test, our pediatric audiologists will use a computer to look at your child’s responses. The audiologist will then analyze the responses to estimate your child’s hearing. Once the necessary information is obtained, the audiologist will discuss the results of the evaluation with you and provide appropriate follow-up recommendations.
Although an ABR appointment is generally scheduled in the morning and estimated to last two hours, the ABR itself does not take two hours to complete. Extra time is allotted within your appointment in case your child wakes up and needs to fall back asleep. If your child is not able to sleep long enough to complete testing, the ABR may be rescheduled or a sedated ABR may be recommended by our audiologists.
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