ABR Test and ASSR Test
I am a pediatric audiologist. I do hearing tests on babies every day. The most common question parents ask me is, “My baby failed the newborn screening. What happens now?” I always explain that the screening is just a screening. It is not a diagnosis. To know if your baby has hearing loss, we need to do more detailed tests. The two most common are the ABR test and the ASSR test. Let me explain what they are and why they are safe.
What Is an ABR Test
ABR stands for Auditory Brainstem Response. This test measures how the hearing nerve and the brain respond to sound. Small stickers called electrodes are placed on the baby’s head and behind the ears. Soft earphones play clicking sounds into the baby’s ears. The electrodes record the electrical activity in the hearing nerve and the brain. The test does not require the baby to do anything. In fact, the baby should be asleep or very still.
The ABR test tells us whether the baby can hear sound at all and roughly how loud the sound needs to be for the baby to hear it. It is a good test for screening, but it does not give detailed information about hearing at different frequencies.
What Is an ASSR Test
ASSR stands for Auditory Steady State Response. This test is similar to the ABR test but more detailed. Small electrodes are placed on the head and behind the ears. But instead of just clicking sounds, the ASSR test uses pure tone sounds at different frequencies and different volumes. The computer analyzes how the brain responds to each specific tone.
The ASSR test can tell us exactly how much hearing loss the baby has at low, middle, and high frequencies. This information is critical for fitting a hearing aid if one is needed. The ASSR test also takes longer, about forty five minutes to an hour, compared to thirty minutes for the ABR test.
Which Test Does Your Baby Need
In my clinic, I often do both tests together. The ABR test gives me a quick answer. The ASSR test gives me the detailed information I need to recommend treatment. Both tests are safe, painless, and can be done while your baby sleeps. There are no needles, no radiation, no risks.
If your baby fails the newborn screening, do not panic. Many babies pass on a follow up test. But if they keep failing, come see an audiologist. We will do an ABR test and an ASSR test. We will give you answers. And then we will help you get your baby the support they need. Early detection of hearing loss is critical. Babies learn speech by hearing it. The sooner we know, the sooner we can help.