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