EMG testing and MS?

[biowham]

I have a question about EMGs and NCTs, and I can't seem to find an answer anywhere.

What are the expected/typical/indicative results of EMG/NCTs in the context of MS?

I ask because I had only two abnormalities, both in my right hand, on EMG/NCT...reduced amplitude in a motor nerve (half of the lt side amplitude) on NCT, and spontaneous activity at one site on EMG, also in the right hand. Lt hand EMG/NCT were normal. Right foot--which is now almost completely numb, quite tingly and zappy--was normal on NCT. She opted not to do EMG on that leg b/c I'm going for the MRI.

Would one expect to see more abormalities on NCT/EMG in the MS picture?

Gracias--
Emily

[shoshin]

My understanding is the EMG and NCV only test the function of the peripheral nerves (and then only the large fiber ones; you can have small fiber peripheral neuropathy and not have it be picked up on these tests). So I don't think you would expect any abnormalities from MS since MS only affects the central nervous system. What was explained to me is that even though I feel the symptom in the peripheral nerve areas, with MS they are caused by problems in the signals while they're in the central nervous system (going to and from the peripheral nerves).

They can also do several types of tests called evoked potentials (EPs) and these test the central nervous system and are often abnormal in MS (but not always). That was what made them think MS or something in the central nervous system in my case.

Hope this helps a little and hopefully someone who know more will weigh in.

[treebranches]

From what I've been told, shoshin is right.  My understanding is also that they do the EMG/NCS to tell whether there "major flaws" that would be a sure sign of other disorders like Lou Gehrig's, muscular distrophy, carpel tunnel, pinched nerves, etc.  As far as I know, the results won't say "yes, MS" or "no, not MS", either way; I could be wrong.