EP

An evoked potential (EP) test measures electrical signals in the brain in response to stimulation through sight, sound or touch. The test can help diagnose conditions of the brain and spinal cord such as multiple sclerosis (MS). MS is a condition that can cause visual, movement, balance issues and other symptoms.

There are three types of EP tests commonly performed:

1. Visual Evoked Potential (VEP)

Checks the nerves that connect the eyes to the visual cortex. The visual cortex is the part of the brain that enables us to see.

2. Brainstem Auditory Evoked Potential (BAEP)

Checks the nerves that connect the ears to the brainstem. The brainstem connects the spinal cord to the brain and helps to regulate breathing, heart rate, blood pressure and other functions.

3. Somatosensory Evoked Potential (SSEP)

Checks the nerves that connect the upper and lower limbs to a part of the brain that enables you to feel objects.

Depending on your condition, one to three tests will be ordered by the doctor.

Visual Evoked Potential (VEP)

How should I prepare for the test?

Bring your spectacles, contact lens and all other visual aids that help you see better.
Ensure that you are able to remain in a sitting position for 45 minutes.
Avoid using hair styling products e.g. foam, cream, gel, oil.

How is the test performed?

The test is done by a neuro technologist and takes around 45 minutes.

This test is done while you sit on a chair.
Electrodes are placed on your scalp.
Look at and focus on black and white checkered patterns shown on a TV screen about 1 metre away. If you are sensitive to flashing lights or images, speak to your doctor.
The electrodes record your brain’s response to the patterns you see on the TV screen.
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.

Brainstem Auditory Evoked Potential (BAEP)

How should I prepare for the test?

Avoid using hair styling products e.g. foam, cream, gel, oil.
Avoid wearing earrings.

How is the test performed?

The test is done by a neuro technologist and takes around 30 – 45 minutes.

This test is done while you are lying down.
Electrodes are placed behind your ear lobes and scalp. They do not cause any pain.
A headphone is given to you to put on.
A clicking sound is played rapidly through the headphone, first on the left side, and then repeated on the right.
The electrodes will pick up the responses.
Once the test is done, the electrodes are removed and you can go home.
A detailed report is sent to your doctor within two weeks. Your doctor will discuss the findings with you at your next appointment.

Somatosensory Evoked Potential (SSEP)

How should I prepare for the test?

Avoid using hair styling products e.g. foam, cream, gel, oil.
Avoid applying body lotion.
Wear shorts.
Contact 6330 6363 if you have a device implanted in your heart/abdomen (pacemaker) or brain (intracranial device or neurostimulator).

How is the test performed?

This test is performed by a neuro technologist and takes:

a) Around 1.5 hours when done on the arms or legs.
b) Around 3 hours when done on both the arms and legs.

This test is done while you are lying down.
Electrodes are placed on your scalp, neck, lower spine and back of the knees.
A small electrical impulse is applied repetitively to your wrists, ankles or both areas till your thumb or toe twitches.
The test is done on one wrist or ankle at a time and repeated on the other side.
The electrodes will pick up the responses.
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

Are these tests safe?

The tests are generally safe as there are no known side-effects or complications. The neuro technologist will be with you throughout the process. If you feel unwell, tell the technologist.

Can I undergo the test if I am feeling unwell?

No. If you are feeling unwell e.g. fever, cough, do not proceed with the test. Call to reschedule your appointment.

Have questions or concerns? Call:

Tel: 6330 6363

Office Hours:
8.00am – 5.30pm, Mon – Wed, Fri
8.00am – 5.00pm, Thurs
Closed on Sat, Sun, Public Holidays

Click here for directions to: