I noticed a bit of a contradiction in this article: in one sentence, the researcher talks about reduced firing rate of neurons, and then immediately talks about the muscles not listening. From this, I'm not really clear about whether one or both things are happening.
I would think it's probably more likely, (and more relevant to MS), to be the reduced firing rate of neurons. The strength and speed of a movement is directly related to the strength and speed of the electrical signal firing from the nerve to the muscle. For example, if you were gently holding an egg, and you could hear the pulses in the nerves controlling your finger muscles, you would hear "click...... click...... click", if you decided to squeeze hard and break the egg you would hear "CLICKCLICKCLICKCLICK". so you see, it's not exactly the "distance" that the nerves have to shout, more about how loud and fast they can shout.
Sometimes I think that MS sounds more like accelerated ageing in the brain than anything else.
Sounds to me like your progressive doc is a good one: he's used the phenomenon of "plasticity" to overcome your balance problems. This is where, if the bits of your brain which are used to control something are damaged for any reason, repeatedly trying to do the same movement forces your brain to make new connections and reinforce them with constant use. That's what a baby does -- strengthening the circuits which work, and discarding the ones which don't. All credit to you for sticking at it so successfully. Give it a couple more months and the job in the circus is yours
With the weekend coming up I didn't want to blow your own mental circuits with anything too taxing. Your wife needs you, and you need her to bake you a nice "congratulations on your 1000th post" cake. (Note to all readers: please send your complaints about outdated sexual stereotyping to: Mr R Lyon, somewhere in Michigan).