An EMG is a nerve conduction study, If a nerve is impinged or damaged the small amount of current they run from one needle inserted at point A to the needle at point B and back. Current should flow freely from one point to another and back again, when a nerve is impinged it slows the flow of current or disrupts the flow they know there is a nerve problem, The only problem with the acuracy of these tests is that they don't have a base line to compare it with. Not everyone is wired exactly alike so if they haven't done a study on you when your healthy they are comparing the reults to what is supposed to be the average person, whatever that is.
I have an extra lumbar vertabrea so some of the nerves that would normally flow out from L5 are split and run from L6, So my EMG wouldn't apear to be normal compared to the general population in those specific nerves. Honsestly I think EMG's are just money makers, No doc is going to operate based solely on the reults of an emg without other significant findings from other diagnostic tests.
If an EMG is abnormal but every other test is nornal, I doubt the EMG info is really that valuable.Just my opinion though. Some folks say they are uncomfortable to have done and for some it's no big deal. Needle placement in certain areas can be more uncomfortablke than others, but having a small amount of current run through a nerve really isn't that painful IMO. Everyone is different though and perhaps strange results on an emg may lead to more diagnostic testing.
Take care, Dave