Here's a thought, Abby.

We have 640 skeletal muscles, all of which can be affected by MG. Every time a muscle becomes weak, think of a small weight being attached to them. When muscles are weak, they can feel "heavy." Sometimes it's only a particular muscle group we have used, such as our arms/hands after typing. What you are describing is many muscle groups becoming weak, which would make you feel like you can't move well or at all. They literally can feel heavy.

I think it's more like a spectrum of weakness than a different kind of weakness. If weakness were a color, like periwinkle, it would run the spectrum from vibrant to pale. It's the same color, only "weaker."

Rachel, Here is the link: http://neurotalk.psychcentral.com/thread133396-2.html

In that study, they are saying D-MG are those patients with a decrement on an RNS (repetitive nerve stimulation test) and ND-MG is "no decrement" MG. They are comparing patients without MG to those two groups too. Does that make sense? Bottom line of that study is that the degree of decrement relates to how weak someone with MG is but not to a level of fatigue (tiredness). DUH, as if we needed a study for that.