What is the difference between a screening ABR and a diagnostic ABR?
Automated Auditory Brainstem Response (AABR) is used as a screening test in newborn babies; it is a pass or refer test. Newborns are screened for hearing loss before they leave the hospital and if they do not pass the screening, they get a second screening within 2-4 weeks. Screening tests are performed using one loudness level and the newborn either passes or refers the screen. Infants not passing the screening in one or both ears after two attempts are referred to a pediatric audiologist for a diagnostic ABR evaluation. The ABR further tests their hearing at different volumes and pitches. Babies that do not pass the screening get a result called refer. This is because not passing a screening does not mean that your baby cannot hear; it does mean that further testing is needed to see how much your baby can hear. Not all babies that refer on their hearing screenings have hearing loss. Nevertheless, It is important to identify babies that do have hearing loss as soon as possible, because unidentified hearing loss can have a significant impact on how well a child learns to talk.
If your baby does not pass the hearing screening and is referred for a diagnostic ABR it is important the test is completed by 3 months of age, identifying hearing loss early is important to the early development of communication. Research has shown that hearing loss identified after even 6 months of age can effect how well a child learns to talk and listen, thus emphasizing the importance of early identification.
Who can be tested using an ABR?
ABR can be recorded in newborns, infants, children, and adults. An ABR test is performed during sleep or during a quiet period, because noise and movement can affect the test results, if the child is younger than 4-5 months of age, an ABR can usually be done while the baby is asleep. An ABR testing with sedation is recommended for children who are unable to sleep naturally or rest quietly during the test. Sedated ABR testing is also recommended for older children if there is a concern or suspicion of hearing loss that cannot be confirmed by standard hearing testing.
What do you need to do before you bring your child in for an ABR evaluation?
The ABR appointment will take about 2 hours, and it is very important for the baby to sleep during the entire test. The best way to prepare for the test is to keep the baby hungry and tired prior to your appointment. Try to keep the baby awake and hold the feeding right before your appointment until the time of the appointment or until the Audiologist is ready to begin the test. If possible try to keep your baby awake during the drive to our office. It is recommended that you bring a blanket or anything that provides comfort to your baby while sleeping. The goal is for the baby to sleep for 2 hours as soundly as possible, the better your baby sleeps the faster and more accurately the ABR testing can be completed.
What does it mean if the test results are not normal? What are the next steps?
When test results are not normal, the audiologist will provide more details about your child’s hearing when the ABR is finished. Abnormal test results are mostly associated with a hearing loss that needs further follow-up. This includes meeting again with the audiologist, but also with a pediatric ear, nose and throat doctor (ENT). The ENT doctor will complete a full medical work-up. At PENTA, you will usually be able to schedule this follow-up appointment on the same day. If hearing loss is identified and confirmed and medical management cannot help the hearing loss, hearing aids will likely be recommended. It is our goal to have these hearing aids fit no later than 6 months of life for babies identified from the newborn hearing screening.