Brainstem Auditory Evoked Potential (BAEP)

What is Brainstem Auditory Evoked Potential (BAEP)?

BAEP is a test that records how quickly and effectively electrical signals in the brainstem is received, in response to auditory stimulation (sound). 

Your doctor may recommend this test to:

• Evaluate the function of the hearing pathways and brainstem. The brainstem connects the spinal cord to the brain and helps to regulate breathing, heart rate, blood pressure and other functions.
• Help diagnose conditions of the brain and spinal cord such as multiple sclerosis or brainstem lesions

How should I prepare for BAEP?

• Avoid using hair styling products e.g. foam, cream, gel, oil.
• Not required to fast.
• Continue with your regular diet and medications.

How is BAEP performed?

The test is done by a neurotechnologist and will take approximately 30-45 minutes.

• This test is done while you are lying down on the bed.
• Your scalp is cleaned using a gel.
• Small markings are made on your scalp and behind your ear lobes. 
• Electrodes are attached to the marked areas using a safe and washable paste.
• A pair of headphones will be provided for you to put on.
• Clicking sounds will be played through the headphones; sounds may be played in both ears, one ear at a time and with varying volume levels.
• The electrodes record your brainstem’s responses to the sounds. 
• Once the test is done, the electrodes are removed, and you can go home.
• A detailed report will be sent to your doctor within two weeks. Your doctor will discuss the findings with you at your next appointment.

Frequently asked questions about BAEP

Is the test safe?

Yes, the test is: 

• Non-invasive (no needles).
• No external electric current or discharges. The test only records your brain’s electrical activity – it does not send electricity into your body.
• A neurotechnologist will be present throughout the process. If you feel unwell, please inform the neurotechnologist.

How loud are the sounds I’ll hear during the test?

The clicking sounds will be just loud enough for the electrodes to record the brainstem’s response (60dB above your lowest hearing threshold, similar to normal conversation).

Can I talk during the test?

It is best to avoid talking during the procedure, as speaking, moving or swallowing might affect the test results. 

Can I use Medisave to pay for this test?

This test may be claimable under:

• Flexi-MediSave for Seniors; or
• Outpatient scans for diagnosis or treatment of a medical condition. 

Please refer to the Ministry of Health's Outpatient Care page for the latest claim limits and eligibility criteria.

The information is correct as of July 2026 and subject to revisions without notice.
Content adapted from NNI Neurodiagnostic Laboratory (NDL), NNI@TTSH.