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Evoke potential test!

I saw the neurologist on Thursday and he’s sending me for an evoke potential test. He mentioned radiological isolated syndrome because my LP and neuro tests are normal but i have lesions on my brain scan. I am confused.

It’s an evoked potential test. It’s probably a visual one (VEP), which is quite long-winded but completely painless, and involves sitting in a darkened room, with electrodes on your head, and looking at chessboard-type patterns. They are measuring the time taken for nerve signals from the eye to reach the back of your brain (where visual processing is done), as any delay could indicate inflammation of the optic nerve - quite common with MS.

Sometimes they do similar, but stimulate the nerves of the arms or legs, to see how long it takes the signal to arrive at the brain. Again, any delay could indicate damage to nerve pathways, typical of MS.

I have heard of clinically isolated syndrome (CIS), which means a single MS-like episode, which may or may not ever go on to become MS. Until you mentioned it, I’d never heard of “radiological isolated syndrome”, but apparently (Thanks, Google!) this is more commonly used when the person has experienced no symptoms suggestive of MS, but MS-like lesions have been found by chance, when doing an MRI for some unrelated reason!

Sorry, I cannot remember the history - were you originally being investigated for MS-like symptoms (even though your neuro exams are now normal), or did they spot something unusual when you were investigated for something else? It’s not common for anyone to find out by chance they had brain lesions, but does happen.

Tina

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I was given a brain scan because of vertigo, headaches and fatigue etc but i haven’t been well for 13yrs and i was given a diagnosis of m.e/cfs years ago. Because my scan showed lesions i was then sent for a LP which has came back negative and my neuro tests were ok so he said he can’t ignore the fact my scan isn’t normal and wants to get to the bottom of it so he’s sending me for the evoke potential tests. I don’t know what he will say if that’s normal.

It IS possible to be diagnosed with normal VEPs, because I was - and I didn’t even have a LP, so we don’t know what that would have said.

But no one test by itself proves or disproves MS - they’re just another piece in the jigsaw. If it comes back normal, it won’t prove you haven’t got MS, but if abnormal, it lends weight to the theory you have. Doesn’t necessarily mean you would be diagnosed, but it all contributes to the picture.

Tina

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Hi Zipster-

I was told I had had a ‘radiologically isolated event’ after lesions were found on a brain MRI during assessments for MS. There was not enough on initial MRI for MS diagnosis - (have just had repeat MRI, and was told that if further ‘radiological evidence’ is found, diagnosis may be changed to MS). So very similar to CIS i think!

I have read online about RIS being diagnosed when lesions are found incidentally, like tina said. But in my case, the mri findings were not incidental… I had been complaining of tingling leg, chest pain, other issues for 18 months!

But - I think in order to diagnose CIS, there needs to be subjective and objective evidence that an event has occured. Unfortunately, in my case, the doctor saw me quite a while after the ‘event’ (18 months later) … so there was no way he could observe / confirm the symptoms I had had.

Also, evoked potentials came back normal, and physical exam only showed minor issues (slightly brisk reflexes, slight clonus, slightly weak hip flexion). So I was told my history and exam were ‘inconclusive’.

I am wondering whether this is why I was diagnosed RIS not CIS - the doctor could not verify the main event so to speak, and physical exam was inconclusive, so for diagnostic purposes, not a definite isolated event. But later mri showed lesions, so ‘something’ had occured… although no verified ‘event’ to tie it to.

At least that is my understanding of my situation, though i may well be wrong… it is all so confusing!

would be interesting to hear from others with this diagnosis.