Like all the others a doctor is best bet. I'm still waiting for the docs to confirm at this point, but have long suffered floaty-torso syndrome, sometimes it's a welcomed relief other times it's just a pain in the butt. Thankfully I can still move the legs even though other than looking down, it really seems like they have left my body.

Don't know if it's from ms or my back injury though and even the doctors don't really know what to make of it. They seem to think if I can feel anything at all then the legs can't move or support me. They can, though I do still fall on occasion since there's nothing to inform me that my foot is turned wrong or my knee isn't fully extended yet or I'm stepping just right on a lip but once the weight goes down so will I.

I've gotten around it by refocusing on my center of balance (position of obliques, abs and back) but largely lucky since I played a lot of sports growing up and everyone of my coaches for anything hammered that into us. Where's your COB?! (On an ear of corn)

But if the leg is going completely paralyzed that's not going to be much help. If your leg seems to disappear I would make sure you can still wiggle your toes before trying to walk on it, and if you can and decide to step on it, watch your leg until you can get the hang of it. If it will hold you don't try to limp or you just put more pressure on the other.

I also take baclofen and the docs don't seem to think its a side-effect of it.