Auditory Brainstem Evoked Response (ABR)

Auditory brainstem response (ABR) testing is a procedure used by audiologists to evaluate hearing sensitivity and determine how well the auditory nerve and brainstem pathways are functioning. This helps with the diagnosis of neurological hearing problems such as acoustic neuromas and other lesions in the auditory brainstem pathways, and can be used as an infant hearing screening test. It is sometimes referred to as auditory evoked potential (AEP).

Patients undergoing ABR testing will have electrodes attached to their scalp and earlobes. A series of clicks or tones are delivered through earphones, and the electrodes measure brain wave activity in response to this sound. The electrical responses are plotted on a chart in a “waveform” that provides information on the length of time it takes to respond to the stimuli. Delays can indicate the presence of acoustic neuromas or other abnormalities in the auditory pathway.

Patients are instructed to lie down and relax as much as possible during the test. Restlessness and movement can cause overstimulation that leads to false readings. Anesthesia or a light sedative may be given to help with relaxation.

Results from the ABR are used to help diagnose hearing loss and nervous system disorders, especially in newborns and young children. The test can help identify hearing loss in patients who are unable to undergo conventional hearing tests, and can be helpful in fitting hearing aids in those individuals. ABR results can also point to brain injury, tumors, speech disorders and stroke. Testing is completely safe, with no risks or side effects.