VEP on Thursday

hi All, sorry I haven’t been on lately but have been struggling the last week or so to actually get my head around it all!!

I’ve got my VEP test on Thursday, funny but I’m not looking forward to it, I think it’s the unknown.

Spoke to my GP today as had to go on triage list as the juddering has got worse and much more frequent, and my left ankle and foot keeps swelling. He has sent a fax to my neuro to check what he wants him to do. Feels it is water retention but reluctant to give me tablets for it as the incontenance has been really bad this last week or so.

I’m finding the heat is affecting me, I normally love lying out in the sun but can’t as I really suffer, find my arm goes very stiff and can’t move hand and the tingling really increases. The pain in my arm has been horrible today. So much so I resorted to oramorph this afternoon!!!

I’m releaved that the tests will be over after Thursday but worrying as to what the result will be. I know he needs to rule out Devics but will I be any further forward after it. What happens next?

Anyway moan groan over.

Sarah xx

Hello Sarah,

VEP is nothing to worry about, it is completely painless. They put these little electrodes on your head and you watch a screen with loads of dots. Just one word of warning your hair will be a total mess afterwards and feel horrible. First thing I did after having it done was to give my hair a jolly good wash. Nothing to worry about, promise.



Thank you Janest, don’t know why I got so wound up about it!?!?

Just seem very stressed at the moment, the boys can’t do anything without me shouting at them!!! All I seem to be doing is apologising.

The doc made me burst into tears yesterday he was so sweet. Don’t know what’s going on.



Hi Sarah

I had a VEP last Thursday, and its nothing to be worried about - promise. Its completely painless, you just sit in front on a screen and focus on a dot in the centre of the screen.  Worse thing for me was my Mums driving getting there and back! lol

I cant see my GP without crying either, and she said it was a completely natural reaction to not knowing what is wrong with you (plus the tabs I am on can make me emotional too apparently).

Please dongt worry Sarah. The VEP is easy, and you are obviously going to be emotional at a time like this.

Keep reminding yourself that when you get better, you will treat your boys. They will understand and love you no matter what Sarah.

Thinking of you

Paula xx


I have a VEP on Friday. Good luck for Thursday :slight_smile: x

good luck to you too nikjag8 :D xx


Evoked Potential (EP) tests

Evoked Potential tests are procedures for measuring the speed of impulses along neurons. Responses can be measured using EEG readings from electrodes attached to the scalp and occasionally other areas of the skin. Although this may sound like something from Frankenstein, they are in fact completely painless and entirely harmless. Based on input signals to the particular sense being measured, the time taken for that response to register can be accurately measured and compared to normal readings. The results are then analysed on a computer and average speeds recorded.

Demyelinated neurons transmit nerve signals slower than non-demyelinated ones and this can be detected with EP tests. Although they may appear to function perfectly, even remyelinated neurons are slower than normal nerves and so historical lesions can be detected in this way.

There are three main types of evoked potential test:

Visually Evoked Potential (VEP)

This test measures the speed of the optic nerve. The patient has to focus on the centre of a "TV" screen on which there is a black and white chequered pattern. Each square in the pattern alternates between black and white at measured intervals. The patient wears a patch on one eye for a while and then on the other, so that the speed of both optic nerves can be measured.

85-90% of people with definite MS and 58% of people with probable MS will have abnormal VEP test results.

Brainstem Auditory Evoked Response (BAER)

The BAER test measures the speed of impulses along the auditory portion of Cranial Nerve VIII. This nerve arises in the Pons area of the Brainstem and therefore this test may be indicative of lesions in that area. The patient lies down in a darkened room to prevent visual signals from interfering with measurements. A series of clicks and beeps are played back to the patient.

67% of people with definite MS and 41% of people with probable MS will have abnormal BAER test results.

SomatoSensory Evoked Potential (SSEP)

The SSEP test involves strapping an electrical stimulus around an arm or leg. The current is switched on for 5 seconds and electrodes on the back and skull measure the response at particular junctions. The current is very low indeed and completely painless. The speed of various nerves can be measured in this way and the points of slow-down (i.e. demyelinated lesions) approximated to because of the sampling at several places.

77% of people with definite MS and 67% of people with probable MS will have abnormal SSEP test results.

Any of these tests are not necessarily indicative of MS but can be used in conjunction with a neurological examination, medical history, an MRI and a spinal tap to deduce some kind of diagnosis.


Completely harmless; don’t worry Janet is right.




Thank you Paula and everyone else. I’ve had a neuro appt come through for 13 Aug so won’t have to wait too long!!

Will let you know how get on

Sarah xx

Good luck for today

Thanks xx