Objective test measures are needed to assess hearing for infants and for young children who are not old enough or developmentally ready for behavioral audiological testing. One of the methods used is Auditory Brainstem Response (ABR) testing. ABR testing is also known as auditory evoked potential testing. ABR testing allows us to estimate hearing levels based on neurological activity in the auditory system. Sounds are introduced through earphones while electrodes are placed on the patient's head to measure brainstem electrical activity. ABR is a pain-free test but requires that the patient be very still or asleep. Sedated testing is available if necessary.
- Newborn Hearing Screening using Automated ABR
Newborns at our medical center undergo hearing screening using an automated form of the Auditory Brainstem Response (ABR) test. Newborn hearing screening is required for all infants born in North Carolina. Full term babies can be tested in the first 24 to 48 hours of life. Premature infants should be at least 34 weeks post-conception before testing. The newborn hearing screening program at WFBMC is managed by Audiologists in the Hearing and Speech Department.
Diagnostic ABR testing is performed when an infant fails to pass the newborn hearing screening after at least two attempts. Diagnostic ABR testing can also be performed on children when hearing cannot be reliably evaluated with routine behavioral test methods or other objective tests. Auditory brainstem response (ABR) testing is available using both clicks and tone bursts to estimate hearing at different frequencies. The estimated hearing levels and ABR response characteristics can help to establish the degree and type of hearing loss. This information can help to determine if the hearing loss might need medical management and it can guide in hearing aid selection and programming if the hearing loss is permanent.
- Auditory Steady State Response
Another type of evoked potential test, called Auditory Steady State Response (ASSR) testing, may be used in some cases for additional information, especially if severe hearing loss is suspected.
Except with very young infants, sedation is usually required to perform ABR and ASSR testing on babies and young children. When sedation is needed, our tests are performed in the Pediatric Sedation Suite within Brenner Children's Hospital. The child is assessed by the medical staff to determine if it is safe to sedate, and the child is monitored by a physician and a nurse while testing takes place. The test is not painful or invasive but the child needs to be very still for an hour or more to obtain complete information.