Evoked Potential Evaluations

Image courtesy of Natus Medical Incorporated

Auditory Brainstem Response (ABR)

A Diagnostic ABR is a computerized evaluation which is used to measure the brain wave activity your ear produces when it hears sounds. Sometimes an ABR is called BAER (brainstem auditory evoked response) and may be automated or diagnostic.

An ABR test is ordered when complete results cannot be obtained with a routine hearing test (audiogram), often with infants and young children. If there is a hearing loss, the ABR helps to determine the severity of the problem.

An ABR is also often needed when a simple hearing test shows a certain type of hearing loss pattern. The test is extremely helpful in ruling out or confirming auditory nerve lesions such as acoustic neuroma. In addition, it is helpful in diagnosing demyelinating diseases such as multiple sclerosis.

The test, whether diagnostic or threshold, usually takes one to two hours. It requires the patient to lie very still so the computer will not pick up any muscle movement. Flat electrodes (or wires) are taped to the forehead and ears. These electrodes will measure the response to sound from the ears and brain. Clicks are emitted through earplugs, and your brain’s response to the sound will be recorded by a computer and analyzed by the audiologist.