EMG questions
 

Hi there, I have some questions.

1) will the result of an EMG say something about the severity of the disease?

2) will the result of an EMG on the hand be very different from the result of an EMG on the leg, if you have more weakness in the leg? (So, do you have to say: please do the EMG on ... whichever is the weakest?)

3) will the result of a sfEMG say something about the severity of the disease?

4) if they do an EMG on your nose or your eye, is this a sfEMG? Or can this also be a normal EMG?

I'm most interested in the first and last question.
Sorry for my abstract and uncosy way of asking, but else I just blab on and that's annoying :p

Thanks :hug:

I had the single fiber EMG done at the mayo clinic about my eyebrow. It came back negative so they weren't sure about MG. We re did the blookd work multiple times for the ACHR (I think thats right) just to confirm and it was abnormally high each time. The only weakness I had at the time was bulbar weakness and some eyelid weakness. That was just my experience, they tried on the the arm with no luck as well.

I don't have all the answers, but here's my experience for what it's worth.

I had two SFEMGs on my arms and legs. They came back "borderline" and "mildly abnormal." Then the neuro sent me to an extra-special specialist, who did an SFEMG on my face, around my eyes. I have no noticeable symptoms in my eyes--no ptosis, no double vision, no face-droopiness. That third SFEMG came back so clearly abnormal that it got me a diagnosis.

The doctor who did it (a specialist in MG) said that it didn't matter that I didn't notice symptoms in those muscles. He also said that the results were severely abnormal, and not just mildly abnormal.

Abby

I had an sfemg around my eye muscle and it came back very abnormal. There were scores that showed the subsequent decrement on re-exciting the muscle. So there is a measurement they can take but I am not sure how it relates to clinical severity. My eye muscle visible tremble with weakness before I took the test.


kathie

Okay thanks for all your answers!

So, if you get an emg in your face, you're probably getting a SFemg?

This is the usual algorithm for EMG's, though it can change depending upon which muscles are more weak.

When they do an RNS, it's normally done on the EDC muscle (forearm) but it can be done anywhere depending upon your clinical weakness.

Regular EMG's can be done anywhere but they're normally done on the arms and legs and not the face. Yeah, there are exceptions but I'm talking about MG specifically.

SFEMG are often done on the EDC, frontalis (forehead), deltoid (shoulder) or the facial/ocular muscles. They can be done on the leg muscles too. It's too dangerous to do them on the chest wall muscles.

From what I've read and have been told, a SFEMG can be normal on a clinically weak muscle and abnormal on one that's not weak. ;) There are so many variables that come into play when doing a SFEMG: Hydration, warmth of muscles, technician's experience, how results are analyzed, etc. Subcutaneous fat of 9mm, which lies above the muscles and under the skin, can reduce the signal by 80%, exactly what can happen with an ECG of the heart. Some studies show that men's muscles fatigue more quickly than women's do, which might be why women are in charge of "the household." ;) Just kidding. That might be why women often have a negative SFEMG and might need a longer one to show weakness.

The EMG result will not necessarily show the severity of your disease. Your symptoms and a good clinical exam are best to do that! And breathing tests too.

Questions, even if you're babbling, aren't annoying!!! And YOU aren't annoying. MG is. I hope the test goes well.

:hug:
Annie

EMG tomorrow
 

Did others get information immediately after the EMG or does one have to wait to hear from the neuro who ordered the tests? I have my EMG and CT scan tomorrow.....I'm just nervous, I guess. :(