Auditory brainstem response is a test that is use to measure hearing loss.

ABR testing is not routinely done as part of the hearing evaluation but will be done when the patient’s test results suggest that the damage is somewhere deeper in the auditory chain than just in the cochlea (e.g. in the brainstem). For this test, electrodes are placed on the patient’s head and ears and sounds are played to the patient through earphones, extracting responses from the ongoing electrical activity in the brain. The responses are then recorded to determine if there is damage to the auditory nerve pathway. The test is painless and harmless and can even be done on babies and small children. The patient has to be quiet or even sleeping during the procedure to ensure optimal responses.