retesting evoked potentials

[murphy01]

Hello,
I have had ms for 14 years.  The first 5 were with attacks and remissions, the next 8 no problems at all and now I have recently had optic neuritis.  Years ago, I was given evoked potentials and an mri and was told I had MS.  Can anyone let me know why or what purpose repeating evoked potentials would do given that I already have the diagnosis.
Thanks

[ShadowsSister]

Hi There,
.Just some added info. I had  these test several times after being DX. This might have been because the MS progressed so rapidly. I had them every six to nine months for the first three years  and then once a year for another three years there after. They used them to help track the progression. They stopped when They caused seizure activity a few times. I think one other reason was I had too much spasm actitity to complete the MRI's.
I don't know if this info is useful or not... but thought I'd pass it on.
{{{{~!~}}}} DJ

[essdipity]

Thanks, Lu. Very interesting. Funny, but I don't remember anyone here saying their docs order repeats of these tests, maybe not even when they were normal on first go. But then I'm not betting on my memory these days.

ess

[Lulu54]

from MS-Network ....

Evoked responses play an important role when diagnosing MS and in assessing the development of the disease. They make it possible to detect changes in nerve pathways that do not lead to obvious symptoms and impairments. Changes in nerve pathways can also be detected by means of evoked responses when the symptoms have been in remission for a long time or occurred several years previously.

[Lulu54]

From the M S Gateway site sponsored by Bayer Health --- this is what they say about EP's and their use.  It can be used after the DX of MS to study the patient's progression of the disease but I would think an MRI would be more effective.

Evoked potentials
In MS, conduction in various nerves is slowed down, because the myelin sheaths which cover, insulate and protect the nerve fibres are damaged. In these areas of ”stripped” nerves, transmission of impulses is markedly delayed.

When measuring evoked potentials (EPs), the time it takes for a stimulus to reach the brain must be precisely recorded. Delays are detected by comparing the test results with the time it normally takes to transmit impulses in people without MS.

By measuring the brain’s electrical activity, neurologists may find lesions that do not cause clinical symptoms. Non-invasive techniques such as evoked potentials, which reveal the brain’s electrical response to certain stimuli, are still valuable, especially for someone for whom the diagnosis is in doubt.


Evoked potentials can help neurologists find abnormalities in nerve conduction and so-called “silent” lesions in the central nervous system, even when no neurological deficits have shown up so far.


Evoked potentials are not only useful for diagnosing MS they are also important indicators of the course of the condition.



Visual evoked potentials
Visual evoked potentials (VEPs) are most commonly performed in the framework of an MS diagnosis. The time it takes for the optic nerve to transmit visual information to the brain area primarily responsible for processing visual information is measured by capturing VEPs.


In preparation for this non-invasive test, electrodes are placed on your head which detect electrical activity (brain waves) within your brain. In order to measure the impulses travelling along the optic nerve between eyes and brain, you are asked to focus on a chessboard-like screen with a tiny square in the middle.


Damage to the optic nerve can cause an abnormal VEP. Therefore such a finding in a person with clinically normal vision may help support the diagnosis of MS, since abnormal VEPs are seen in 75–97% of MS patients.

[essdipity]

Hi, Murphy, and welcome.

If you have MS, there is no reason to repeat evoked potentials. They are a diagnostic tool only.

Have you not been having follow-up MRIs all these years? That's a much better tracker of disease progress. And are you not on a disease modifying drug? On this forum we tend to be very proactive about treating MS. It can be so dangerous not to.

I hope you'll take some time to look over our Health Pages (yellow icon in upper right). We have some very knowledgeable contributors who help keep us all informed that way.

Again welcome,
ess

[Lulu54]

Redoing the evoked potentials test can give your doctor an idea of the course of your disease.  Its not just a diagnostic tool.  Now that you do have ON,  the neuro probably wants a better idea of what lesions might be lurking.  An MRI could probably do the same thing, but that's just my non-doctor guess.

Welcome to the forum here - I hope you find the information and company useful.

be well,
Lulu