Evoked Potentials - advice from experienced folk much needed!


at last appointment, the consultant looked at recent brain MRIand said ‘definitely MS’, but that was a few weeks ago now, I have not had any written letter confirming diagnosis.

I was sent for evoked potentials test, had it done yesterday…- which was a bit odd, especially the feet ones! but ok really.

BUT I am a bit confused as to why the test was done, given that I was told at my last appointment that it was ‘definitely MS’. . So I keep thinking ‘what happens if evoked potentials come back normal?’ - will they revoke the earlier diagnosis? (odd as it sounds I honestly I can’t decide in my head whether or not that would be a good thing - obviously if I were to be told it is not MS after all, it would be a relief - but it would also leave me confused and back in limbo-land!)

So I am now awaiting letter from consultant about the discussion we had several weeks ago, when he said ‘definitely’ ms - AND also now waiting results of ep tests, which will probably take several more weeks. I know its not possible to speed up results, but my mind is whirring off in odd directions, largely as a result of all the waiting!

My main question is : Do people with MS always have abnormal results on evoked potentials? I have looked on web and found different info - one site said most people with ms DO have abnormal results.

So again I think ‘ok, but what if my results are normal - would that mean earlier diagnosis based on brain mri would be changed?’

Has anyone ever been diagnosed with MS with ‘normal’ responses to EPs?

thanks for any info you are able to give xx


MS is notoriously difficult to diagnose, so ideally, they like corroboration from more than one source. However, I am diagnosed on symptom history and MRI evidence alone, after I declined a lumbar puncture, and evoked potentials came back normal - I only had the visual ones (VEP).

So, in short, “normal” evoked potentials don’t mean you couldn’t have MS. It may mean they are slightly more cautious about the diagnosis, and want to wait for more evidence before confirming it.

It seems it’s not uncommon, by the way, for patients to be “told” they have MS, only for the subsequent letter (where there is one!) to appear much less certain. This is exactly what happened to me - I thought I was diagnosed; when the letter came, it appeared I still wasn’t!

For me, it was only a case of playing the waiting game. I think my neuro knew from the start it would turn out to be MS - that’s why he was not reticent about telling me. But I didn’t realise how many evidential boxes he had to tick, before he could put it in writing!