I am scheduled for the Single Fiber Muscle ???? Is this where they remove a bit of muscle? Please give advice as to proceedure or what I should be aware of before this test.

If the MG Neurologist is practically positive I DO NOT have MG - definitely have a neurological condition - but he was pretty adamant it was NOT MG as was being dx'd previously. (This dr is an expert in the research and field of MG) so, if he is that positive - why would he still want to do a single fiber test.

I do have hyperplasia of the thymus and with infiltration to heart and lungs so he is also doing a MRI after we just did CT scan of chest area.

Is all this really necessary??

Bear in mind, I FINALLY have a doctor who is on my side and going to look outside of the box for my diagnosis.

Any thoughts are greatly appreciated. Thanks.

Is it a "single fiber EMG"? I've had this test twice. They will insert very fine needles (like accupuncture needles) into your muscles and then ask you to tighten the muscle very slightly while they measure the electrical impulses being generated. The needle will stay in each place they check for a long time--maybe five minutes.

In my experience, the needle doesn't hurt unless it hits a sensitive place. The doctor told me that if this happens, to tell him and he would move it. So that helped a lot.

The test takes a long time--maybe close to an hour--but there's no pain afterwards. Just make sure you're nice and warm (being chilly can obscure the results) and if you're on Mestinon (Pyridostigmine) you should stop taking it before the test. Some neuros say twelve hours and some say twenty-four. There is one study that says up to two weeks is best. http://www.ncbi.nlm.nih.gov/pubmed/2540433

That's the only "single fiber" test I know about! If there are others, I hope someone here will describe them. The single fiber EMG is a very good test for diagnosis MG. There are some people here who are sero-negative (their blood tests negative for the antibodies that cause MG) but who are diagnosed with MG on the basis of their symptoms plus a clear single fiber EMG.

Hope this helps--feel free to ask more questions.

Abby

Tresa, Abby's advice is the very good. As someone who has had 2 SFEMGs and they were both negative I will relate what I think were the reasons this happened beyond just the fact that this is a test VERY dependent on how good the person is that is doing it.

My first one was at the university I am seen at. It was done in a basement room that was so cold I asked to delay getting undressed/and to have a blanket. All my muscle nerve tests were done in this cold area and tho I always remarked how cold I was it never made any difference to them. My current neuro did mine. I think I was actually the first one she did at the university as she is new muscle neuro they finally found. They had none for some time. The room was small and it was 'more convenient' for her to do my right forearm. I noted that my left was my weakest side. She said it made no difference. I regret now not pursuing that. I had been without mestinon since the nite before.

The #2 one was at Mayo in late November 2008. They take a warm room very seriosuly. But that was the first winter I learned how much better my muscles do in winter. I kinda have a level of remission. Like today I went for literally a brisk walk a little over a block in 24 degree weather! For me that is a miracle. They had me stop the mestinon the nite before and did the test about 3pm. Now I am very very sensitive to all meds. I literally take childrens doses per se. So me being off the mestinon I think in both situations wasnt enough.

I just read about someone saying here that womens muslces fatigue slower. It also said to exercise, be acitve before the test. Prior to the first test I had been on the ward in a hospital bed since the afternoon before. My breathing was worse from stopping so it wasnt like I was jaunting about the halls.

I need another set of emgs. But it will need to happen where they know to warm the muscles and certainly NOT in winter for me.

Annie59

Thank you so very much - I was afraid it was going to be a muscle biopsy. When I had my 1st exam with my new MG specialist, he did the muscle exam and then he came in and stuck needles in various areas and I had to squeeze the muscle etc.

The next test will be Jan 5 - almost two months since 1st time.

I can't have any mestinon until after this test - and I love msetinon but am doing fine so far in this nice cool weather.

But now I at least know what to expect and that's a huge de-stressor!

THANK YOU!

Tresa,


Here is a useful link you might find interesting both before and after the SFEMG for understanding and interpreting the results.

http://www.angelfire.com/retro/micha..._fiber_emg.htm

I go for my SFEMG and a redo of the repstim on Dec 17. Looking forward to the results, not to being off meds for 24 hours.

http://deepblue.lib.umich.edu/bitstr...170720_ftp.pdf also has a great reference table on normal values for different muscles.

Note also that while SFEMG is used to help diagnose MG ( and other Myasthenias) it can also be used to diagnose other NMJ problems as well. Has he said what he thinks the leading contenders ARE?

this reference http://emedicine.medscape.com/article/1832855-treatment does a very nice job showing the actual trace differences of the AP (action potential) recorded during the test.I plan on asking if i can review them with the dr while the testing is happening. my neuro was kind enough to do this. What I dont know if they will let me do if record pics of the trace on the equipment with my cell phone camera. Should have thought of that the first time...

Nan,

I had a brain fog moment, the post I was talking about is in Aby's response (Stellatum), she has posted the link before!

Rachel

Rachel, yep I remembered reading that study as well. It has me a little concerned. I am also making sure to stay clear of caffeine ( affects nmj) and my adviar for about a week or so before hand.... maybe 2 ( which would be tomorrow). I do very little caffeine any more, but occasionally use it medicinally to get me through a dip when I need to be up.

FYI- an update on the Mestinon before SFEMG discussion.
This all comes down to a lo of "know yourself and your body reactions". Since I have only really been consciously dealing with this since early/mid october, I know my reactions very little. I decided to experiment in the name of understanding, so I pretended like today was my SFEMG and stopped my meds yesterday when I am supposed to stop them in two weeks for the test.

While I am seeing a difference, it is not really a full blown expression of what my body was doing. I can not push it further this weekend, due to family obligations and the ned to be together, but I am going to do the experiment next week again, stopping meds 2 days before the "test time" instead of 1 day.

Interestingly enough, I am also finding I am very focused and noticing things about my symptoms I was not before. While my cluster of symptoms was not life threatening or paralyzing, they were fairly debilitating before mestinon. I am only about halfway back to that point right now.

It will be interesting to see what next week brings.. and YES, I am being very careful- always mestinon at hand if I feel at all too bad to handle. I ust want to make sure that I have a good, clean test to get to the bottom of this. Thanks to all of you for your insights into prepping for this.