Negative evoked potential...

Hello everyone,

I have already described in a previous post the reason that brought me here in terms of symptoms, so I won’t recapitulate them all, but basically I had since 3 months some serious sensory symptoms all around my body (e.g. burning, pin and needles, and 3 times sensations of water on the right leg), which all started after a rash on my chest looking like a shingle (which apparently wasn’t, according to my doctors); now these symptoms became less aggressive, but I still have some weird flat red spots that appear everyday on my chest/neck/shoulders, with some weird red spots that last about 30 minutes that sometime appear in cluster/patch on my body when I do some intense physical activity. Everything seems to have started with that rash, but it may not be connected to it. I had very low vitamin D as well when I checked myself after the symptoms (i.e. 12), and ANA tests are negative. My vitamin D have improved now (22), as well as my symptoms (quite significantly, but still sporadically there).

Anyway, I received my results yesterday from my evoked potential test (Somatosensory). I did three of them: 1) laser; 2) and two that were really similar in appearance, working with electrical impulses, but apparently testing different types of nerves. My neurologist told me that everything was normal, which meant according to her that both my peripheral and central nervous systems were fine/unaffected. She appeared to be quite convinced that I don’t have MS, but I will still have two MRI tests in one month; these were prescribed by another doctor.

I read on internet that evoked potential tests are abnormal in about 70 percent of people with MS (especially those who have a history of sensory symptoms), but I was wondering whether this figure sounds accurate or not? I also read that about 30-50 percent of people with MS have ANA positive blood tests. Has anyone heard of that?

My main question is: considering that I have had sensory symptoms all around my body for about 3 months now, how come can my evoked potential tests not notice anything wrong? Would someone with MS and sensory symptoms similar to mine would most likely test positive, or not necessarily?

Thank you very much in advance for your help :slight_smile: wishing everyone a good day or evening!

Blue Marble

Hi Blue Marble, I was told that if Evoked Potentials tests were normal then would only be a 10% chance I had MS. Mine were clear but the Neurologist said it didn’t change her opinion that I do have MS. The diagnosis stage is such a minefield and is indeed the hardest part (so far). I have only minimal symptoms. After the initial shock I felt better once the diagnosis had been made. Really hope that you get answers soon.


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.

Slow nerve responses in 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.

Your 70% is about right.

The only occurrence I can think of with a neurological complaint and blemishes on the skin is with Hughes Syndrome and something called Livedo reticularis, see and

The way you describe your rash does not sound like this but I thought I would mention it.


1 Like

Just to add my experience in for what it’s worth. I’ve had normal visual evoked potentials and SSEP but still have a CIS diagnosis. Currently on Rebif as high risk of conversion to MS due to 2-3 possible brain lesions and LP positive for o-bands. My symptoms are altered sensation in limbs bilaterally mainly at night.

Hey everyone,

Thank you very much for sharing your thoughts and experiences on this particular issue. The period where tests are conducted is indeed a really difficult one, as dragging your mind away from thoughts related to MS is nearly impossible. I found relief in the idea that if MS was to be what I have, or another autoimmune condition, there is still the potential to apply for HSCT, even though this includes some risks.

Regarding the evoked potential, I hope that some other people will be able to share their experience as well :slight_smile:

Newbie2016, if I may ask, what sort of minimal symptoms did you have?

Smurf69, if I may ask as well, what sorts of altered sensations are you feeling?

In any cases, thank to all of you for your consideration.

Take care :slight_smile:

Blue Marble

I only have lhermitte’s sign, the buzzing in my spine when I look down. Occasional uti’s and a but of fatigue.

My symptoms are buzzing/throbbing/numbness in arms/hands and similar but not as bad in feet.

I was diagnosed with MS 2001. Had abnormal evoked potentials x3 and questionable gray matter changes on mri left parietal area. I was having trouble walking, dragging my rt foot and carrying my right arm in addition to extreme fatigue, seizures and muscle spasms. I was started on avonex for about 6 months then changed to betaserone. After about a year of treatment I was able to go back to work as ED nurse. I had exacerbations about 2-3x/year resolved with solu medrol IVs. Was started on tysabri in 2009 and did very well with no exacerbations thru 2015. My MD retired and a new MD fresh out of medical school took over and decided since my mri didn’t show typical ms lesions that I didn’t have ms and took me off of tysabri. I was given high dose prednisone taper of 60, 40, 20 over about 6 weeks and sent packing from neuro MD office and told I don’t have MS and don’t need neurologist. I have had nothing but problems since. I was seen at Cleveland clinic where evoked potentials were done. Each part of test was scheduled to last 45 minutes. The entire testing time that I was actually there was 50 minutes. I was told evoked potentials were normal this time. I was told if normal now, they were probably normal in 2001 and technique was probably not good in testing back then. I was positive JC virus, so no one wants to even consider tysabri, but I am also not getting any answers and continue with trouble walking, extreme fatigue despite nuvigil and several other problems. Can successful treatment with tysabri influence the results of evoked potential tests? I feel like technique on second set of evoked potential testing was much more questionable than in 2001? With the high dose prednisone they gave me, I developed severe joint problems and was dx with seronegative inflammatory arthritis and started on methotrexate by a rheumatologist. I had to have significant C Spine surgery in Dec 2016 and surgeon dc’d methotrexate and started celebrex. I am now having horrible pain, trouble walking, sob, get clammy, diaphoretic and temp goes up to 100.8 any time I try to do anything that requires minimal exertion. Any ideas appreciated.


So far I have had a positive LP, a positive MRI with 1 spine lesion and numerous brain lesion and even though my neurologist is almost certain I have rrms I am being sent for vep’s and ssep’s to help confirm the diagnosis. Has anyone else has similar diagnosis pathway

That sounds almost exactly the same as my journey. I too had one spine lesion and numerous (mild to moderate they described it as) brain lesion load. I had the same tests. i was told by the person performing my EP’s that only 10% of people who have a clear EP will have MS - Clearly I was one of the 10% :slight_smile: On the plus side I have been on the meds (Copaxone) for about 12 months now and my last MRI showed a real improvement and the lesion on my spine has “disappeared”. If anything my diagnosis has been a wake up call to enjoy now, who knows what tomorrow will be for any of us regardless of diagnosis. I have started running, I drink plenty of water and have lost about a stone in weight and all is positive. Good luck with your diagnosis, it is a rough ride but there is a life at the other side of it and it can be a really good one!

1 Like

This may be a silly question…but…have you been tested for Lupus. I was seen by a dermatologist that was adamant that a rash on the chest was indicative of lupus. I know the symptoms of lupus mirror symptoms of MS.