" Couldn't it be denial on the part of the paralyzee? "
I read that in a scientific publication, and I took it that the scientists did their job in eliminating that possibility (I do trust scientists, only don't think of them as saints)
The real issue is that the patients didn't have the ability to move the muscle but behaved as if it were a matter of will rather than power. Maybe it means they are the same thing, maybe it means nothing, it's a curious fact nonetheless (curious enough to make it to a scientific book)
" I mean, when my leg falls asleep to the point of temporary paralysis, no matter how much I want to move it (and often I do, like when I want to walk, for instance) no amount of willpower will help nearly as much as our good ol' friend hemoglobic gettin' down there. I might want to move it in my mind, but if my nerves are unresponsive it don't make no nevermind. "
The issue with those patients is that they reported not wanting to move the limb rather than not being able to. Of course they could be lying.
" Cause and effect relationships are not always reversable (they MIGHT be, but not neccesarily) "
It's always safer to assume they are reversible when we fail to clearly see the cause and the effect. 'Mind' is something which exists only inside your head, as far as the human body is concerned all there is is effect, cause only exists in your imagination.
" Maybe I'm misunderstanding. "
No, like most materialists you are simply confused. You insist on the idea that mind is separate from body while at the same time rejecting dualism. It's an illogical position but you can't see why yet.