Hi,

I'm having a single fiber emg test on Thursday at UNC. They are supposed to be testing the muscles around my eyes since this is where I'm having issues. I'm currently having double vision--no eye droop or other issues yet. I would like to know what to expect. Is the test painful? My initial bloodwork was negative for MG so that's why they are sending me for the SFEMG. I only realized about an hour ago that it involves needles and I'm really nervous now. I would appreciate any experiences that people are willing to share. I'd much rather be prepared when I go to the test. I'm just concerned that the test will be for nothing if a lot of people have false negatives. Just not sure what to think at this point.

Thanks,
Betsy

Hi, Betsy. I have negative bloodwork (three times!) and I've had two inconclusive SFEMGs on my arms and legs. Then I went for an SFEMG on my face, and it came out clearly positive, and I finally got a diagnosis.

The weird thing is that I have hardly any symptoms in my face--so I have the impression that it's a really good test! It's not impossible to get a false negative on an SFEMG, but it's a lot more unusual than getting a false negative in blood work (especially if you have only eye symptoms).

It's needles, yes. They hurt a bit going in, but not as much as a blood test in the crook of the arm does. The needles are thin, like needles that are used for acupuncture. I didn't find them painful once they were in (they have to stay in while the doctor reads the signals). The doctor will either ask you to tighten the muscles slightly, or give you a little pulse of electricity to make them twitch on their own, from an electrode placed on your face. The electricity does not hurt a bit--it's not as strong as the kind you may have had with an EMG!--it just gives you a twitchy feeling.

When I had SFEMGs on my arms and legs, the doctor would sometimes hit a sore spot, and I would ask him to move the needle. But that didn't happen on my face. I don't know if it's because it was a different doctor, or because the nerves in the face are different. Just be aware that if the needle hurts a lot when it is already in place, you don't have to just bear it--tell him he's hit a sensitive spot, and ask if he can try a different spot. The test will probably take about 45 minutes, and you have to stay really still, which is difficult, so make sure you're comfortable--and make sure you're nice and warm! Being cold can give you a false negative.

I hope it goes well for you. I know exactly what you're going through! It's so hard not knowing what's going on. For my first two SFEMGs, the doctor tallied the data while I waited and gave me a report. The third (the one on my face) was so clearly positive that he told me it was positive without making me wait while he did the numbers.

One more thing: are you taking Mestinon (pyridostigmine)? If so, they should have told you to stop taking it before the test. They say at least 24 hours, but I found a study that says Mestinon in your system can give false negatives for up to two weeks. If you need the link, I can dig it up.

Abby

Hi Betsy,
Abby did a great job of explaining what a SFEMG of the face is all about. I didn't find it nearly as uncomfortable as the tests done on my legs and arms.

My SFEMG of my face was negative; however, I received a MG diagnosis with a positive tensilon test and clinical signs. My neurologist told me that the SFEMG can still be negative for someone who has MG, especially if it is ocular.

I hope your test is a pain-free as possible, and that the results help to give you some answers.

Cate

Abby, Is this the one that you called a stimulated emg or something like that? I just seem to remember you or someone had a special kind on the face that worked out after others didnt but I dont recall it being referred to as the SFEMG. And did you say all docs dont know how to do this that it is special?

And I would add that yes if he hits a bad spot say so as at Mayo they tried a number of places including a place in my mid back that sent to the ceiling in pain as it is a really bad spot cause of my scoliosis. He stopped immediately and appologized. I was only off the mestinon for about 18 hours and it was in the extreme cold of winter so I am not surprised the test failed.

Annie59

Yes, the "stimulated" part means that instead of asking me to tighten the muscles, he used electrodes to send pulses of electricity to make them contract. There are a lot of reasons why this test could have come out positive while the other two came out negative. It could have been that it was the stimulated type of test; it could be that it was a different doctor; it could be that it was on my face; it could be that my disease had progressed more by that time. I have to say, it has been making me a bit nervous starting Imuran on the basis of that one test, when the other two were negative. But I have gotten good results from the IVIG, so that's reassuring.

I'm interested to hear that someone tried to do a SFEMG on your back! I was frustrated, at my second SFEMG, that nobody was testing the muscles that were actually weak, and my neuro said that he didn't have numbers for what's normal for back muscles. He said that if it was extreme, he would be able to tell anyway, and offered to try. So he stuck a needle in, hit a nerve immediately, and gave up.

Abby

Thanks for all of your input everybody! I really appreciate it. I think I'm most nervous that the test will be negative but that I'll still have MG but with no definite diagnosis. It's so frustrating but I guess that's one of the issues with MG--the difficulty of getting an exact diagnosis.
Thanks,
Betsy

Abby, in a state of more clarity today the back could have been part of the emg part as they did both emg and SFEMG on me at Mayo. I have to offer they tried really hard in that they did try in a number of places that had not been tried back home. This included my back. I have the report.

Knowing how sensitive I am to medication and cold I do feel strongly that tho they did this all I wasnt off the mesti long enough and was too improved by winter and even colder that day in Novermber. I was so much better I wondered if I was having a remisssion. Thats how good I can get in the winter if I dont get hot on a regular basis. The first winter I didnt tan during winter so that improvement was more profound. Going to tan in winters since keeps the improvement less profound.

Annie59

Hey, I went to UNC also to have mine. I think the Dr.'s name was Howard. I am afraid of needles and I was terrified because I was to have the shock or electric thing also. My husband went in with me. He told me the needles under my eye and over my eye would hurt and it did, only going in. But for someone who is afraid, I kept saying this will be over soon. Due to fear, I gripped the table with my right hand a lot. I had a terrible headache after it was over and my face was very sore afterwards. The funny thing is I didn't have any eye problems. My voice stays hoarse and I am just very exhausted all the time. My legs hurt but they did not do a test for my legs. They also put a needle in my throat muscles to test for them. That was tolerable. Although, he had to do it twice. You will get through this. If I can, I know you can. I run from needles due to great fear, but I did get through this. I talked to him while he was testing and that helped. He was a dire hard UNC fan and my family are dire hard Duke fans. I asked him was it going to make a difference in my pain since we were rivals. You will get through it I promise. Just stay positive and know it will not last long. The hardest part was trying to keep the muscles tightened up during the test. Once the needles were inserted, you really don't feel them anymore. They are very fine. Hope you do well, and don't stress to much like I did. That may be the worse part, stressing. busy

These guys have given you good tips. I won't lie, the test is painful. My eyes water when it's done. You can always ask the doctor to take a brief break if you need it. They don't like to inflict pain on patients! I hope the test goes well tomorrow. You may not get results for a couple of weeks, so be prepared for that! UNC is notorious for that.

Annie

Annie, you got that right about the waiting. That is stressful in itself. busy