Re: Spinal Tap and Evoked Potentials

Posted By CCF Neurology M.D. on February 08, 1998 at 11:17:59:

In Reply to: Spinal Tap and Evoked Potentials posted by JoAnne on February 07, 1998 at 20:36:41:







: I have had three episodes with MS like symptoms. MRIs of brain and neck were o.k.
The Neurologist has given me the choice of having a Spinal Tap and Evoked Potential
test done now, or waiting to see if I have another episode. He has put me on a channel blocker
to help prevent my frequent migraines. We are hoping that the problem is related to
the headaches. If I were to have the Spinal Tap and Evoked Potential test done
when I am not having severe symptoms, would the results still show positive or
negative for MS? I didn't think about asking him until after the appointment.
thank you.
Dear JoAnn,
Although you did not specifically list your symptoms, it is a known that migaines have the potential to cause transient neurological symptoms.  It would be important to note during your next migraine, whether or not the symptoms that you are experiencing have a close time correlation. A normal MRI does not completely rule out the possibility of MS. The spinal fluid, when tested, for MS measures several parameters some of which may be more elevated if performed closer to an attack.  Evoked potential (there are several types depending on your symptoms) can give valuable information regardless of the time of the "flare up".  Evoked potentials are easy to perform and are "painless".  In general, both CSF exam and evoked potential may show abnormalities regardless of when they are performed. In addition, they may pick up information regarding lesions that may be "silent" (Your not showing symptoms).  When combined, if all of these test are negative, the chances of your symptoms being related to MS are significantly reduced.  

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A related discussion, ALS & evok testing was started.