hi catch.

i can understand how the sx's can be confusing.
sensory usually has to do with feeling like you said. like numbness or tingling.
i would consider pain to be neuropathic.

to me, when your legs don't seem to hold you up, i'd consider that to be motor. my legs feel like that sometimes too as most of my sx's are motor related, and mobility related. all sx's and your general clinical picture would be from MS. and if it's from MS that means as a result of lesions and CNS involvement/damage.

it's hard to say if your legs will give out or not. if i get too fatigued or too hot i feel like i could collapse. and i think i would if i didn't get off my feet.

why do you say 2 yrs? what's that marker about?
and, can i ask if you're on any DMD's?
what have your mri's said?
do your tx's help?