An Automated Auditory Brainstem Response (AABR) test is a non-invasive screening used to evaluate a newborn’s hearing. It is a safe method for checking the hearing pathway from the inner ear to the brainstem. The test functions by measuring the electrical responses of the auditory nerve when stimulated with sound. This screening is performed before a baby leaves the hospital after birth. The primary function of the AABR is to identify infants who may require more detailed hearing evaluations.
The Purpose of Newborn Hearing Screening
The primary objective of newborn hearing screening is the early identification of hearing loss. Detecting hearing issues as soon as possible is important for a child’s development, as the first few years of life are a sensitive period for acquiring language skills. Undetected hearing problems can affect a child’s capacity to learn, communicate, and engage socially. Universal hearing screening programs are a preventative health measure to address these potential challenges.
Approximately 0.1% of healthy newborns are affected by severe congenital hearing impairment. Without universal screening, about half of all infants with hearing loss would not be identified by risk factors alone. Early diagnosis and intervention before six months of age improve a child’s developmental outlook.
How the AABR Test is Performed
The Automated Auditory Brainstem Response test is a straightforward and painless procedure. It is performed while the baby is asleep or in a quiet, calm state to ensure accurate results. A test administrator places three small, sticker-like sensors, called electrodes, on the baby’s head and neck. These sensors detect the brain’s electrical activity in response to sound.
Once the sensors are in place, a small earphone is placed over or in the baby’s ears, through which a series of quiet clicking sounds are played. The equipment then measures the auditory nerve’s response, and the automated process generally takes between 5 to 15 minutes to complete.
Understanding AABR Test Results
The results of an AABR screening are “Pass” or “Refer.” A “Pass” result indicates that the baby’s brainstem responded adequately to the clicking sounds at the time of the screening. This suggests the auditory pathway is functioning as expected, though it is a screening, not a diagnostic test.
A “Refer” result means the test did not detect the expected response from the auditory nerve. It is important for parents to understand that this does not automatically confirm permanent hearing loss. Common reasons for a “Refer” outcome include fluid in the middle ear from birth, a temporary blockage in the ear canal, or the baby being too active during the test. Background noise in the testing environment can also interfere with the results.
Next Steps After a Refer Result
If a newborn receives a “Refer” result on their initial screening, the standard procedure is to repeat the test. This second screening may be done before the baby is discharged or scheduled as an outpatient appointment. Should the second screening also result in a “Refer,” the next step is a referral to a pediatric audiologist for a comprehensive diagnostic hearing evaluation.
This appointment should occur when the baby is between four and eight weeks old. The audiologist will perform more in-depth tests to determine if a hearing loss is present and identify its specific type and degree.