What Is an Auditory Brainstem Response Test?

What does ABR stand for?

ABR stands for **auditory brainstem response**. The test is also called:

Brainstem auditory evoked response, or BAER

Brainstem evoked response audiometry, or BERA

Auditory evoked potential testing

Auditory brainstem evoked response, or ABER

These terms may describe similar procedures, although the exact protocol and clinical purpose can differ. Ask the testing center whether the appointment is an automated screening, a diagnostic hearing-threshold assessment, or a neurologic ABR evaluation.

How does an ABR test work?

Sound travels through the outer and middle ear to the cochlea. Sensory cells in the cochlea convert the sound into neural activity that travels along the auditory nerve toward the brainstem.

When many auditory nerve fibers respond in a synchronized way, their combined electrical activity can be detected at the scalp. ABR equipment averages responses to many repeated sounds and separates the consistent auditory response from other electrical activity and background noise.

The resulting waveform contains a series of peaks that clinicians traditionally label with Roman numerals. The timing, size, repeatability, and relationships among these waves can provide information about auditory-system function. The clinician also considers the sound level, stimulus type, test ear, recording quality, age, hearing history, and results of other tests.

What happens during an ABR test?

The exact procedure depends on age and the reason for testing, but a typical diagnostic ABR includes these steps:

The clinician reviews the patient's hearing and medical history.

The ear canals and eardrums are examined.

The skin is gently cleaned where sensors will be attached.

Small recording electrodes are placed on the forehead or scalp and near the ears.

Soft insert earphones are positioned in the ear canals.

Clicks, chirps, or frequency-specific tones are presented to one ear at a time.

The equipment records and averages the electrical responses.

The clinician repeats measurements to confirm that waveforms are reliable.

Remaining relaxed, quiet, and still is important. Muscle activity from blinking, talking, chewing, or moving can be much larger than the ABR signal and make the recording difficult. Babies are often tested while naturally asleep. Adults may be asked to close their eyes and rest.

Does ABR testing hurt?

ABR testing is noninvasive and generally painless. The electrodes record electrical activity; they do not send electricity into the head. Removing the adhesive sensors may feel similar to removing medical tape.

The test sounds can range from soft to louder levels depending on the purpose of the evaluation. Tell the clinician if the earphones, electrodes, or sounds cause discomfort. If sedation or anesthesia is considered, that is a separate medical procedure with its own risks, benefits, consent process, and safety requirements.

How long does an ABR test take?

An automated newborn screening can be relatively brief when the baby is calm and the recording conditions are good. A diagnostic ABR commonly takes much longer—often an hour or more—because the audiologist may test several sound levels and frequencies in both ears and repeat responses for reliability.

The visit may take additional time for preparation, natural sleep, electrode placement, troubleshooting, tympanometry, otoacoustic emissions, or bone-conduction testing. Ask the clinic how much time to reserve for the specific protocol being scheduled.

Automated ABR screening vs. diagnostic ABR

An automated auditory brainstem response screening and a diagnostic ABR are related but not interchangeable.

| Test | Primary purpose | Typical result |
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