Visual Evoked Potential Test for Multiple Sclerosis (MS)

Evoked potential test for MS.

Because of the damage caused to the protective fatty coating of nerve cells, MS slows the speed at which messages are communicated.¹ An evoked potential test is used to measure how long it takes these electrical signals to travel from your brain to your eyes, ears, and peripheral areas, such as your hands and feet. If these signals are travelling slower than they should be, then this can contribute to the diagnosis of MS.²

You might be asked to undergo 1 or more of these tests:^1,3

• Visual evoked potential – measures signals from your eyes
• Auditory evoked potential – measures signals from your ears
• Somatosensory evoked potential – measures signals from peripheral nerves such as your arms, legs, hands, or feet

Before the test, small electrodes will be attached to your head and other areas of your body using sticky pads or sticky paste (don’t worry, that doesn’t hurt). You will then be asked to focus on a specific point on a screen. The pads or paste are removed after the test, but it’s worth taking a hat, hairbrush, or comb with you, to avoid any embarrassing post-test hairstyles.³

You have electrodes put on parts of your body that measure the time it takes for the signal to go from your fingertips to your brain, so really you just need to sit there. You don’t need to prepare too much, just try to relax and listen to the advice of your healthcare team.

Katharina

Living with MS since 2018

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When I was suspected of having MS, I had an MRI followed by the evoked potential test, where they put electrodes on my hands, feet, head, and back. I had to sit a room on my own for a while, so it did make me feel a bit lonely and sad. My advice would be to try to relax and not overthink things.

Grace

Living with MS since 2017

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It depends on whether you receive 1 or all of the types of evoked potential tests. Typically, it takes between 30 and 45 minutes for each type of test

(e.g. signals to eyes, ears, or legs and arms).⁴

There are no specific requirements before having an evoked potential test, but a few things will help:⁴

• Get a good night’s sleep before the test to make sure you can stay alert
• You can eat and take your regular medication as normal

Your doctor may ask you to temporarily stop taking medications that may make you drowsy or sleepy, as these can affect the test

1. Palace J. J Neurol Neurosurg Psychiatry. 2001;71(Suppl II):ii3–8.
2. Chiappa KH. Neurology. 1980;30:110–23.
3. Johns Hopkins Medicine. Sensory evoked potentials studies. https://www.hopkinsmedicine.org/health/treatment-tests-and-therapies/sensory-evoked-potentials-studies [accessed June 2020].
4. MS trust. Evoked potential. https://www.mstrust.org.uk/a-z/evoked-potentials [accessed May 2020].