Chasmo, I really don't know. I can only guess.
What I want to say in essence is that if you want precise movement (as a species) you have to solve the friction problem. What I think is, that the kind of movement that is not functioning any longer in Parkinson's disease, is our answer to that problem. I hope someone will come up with a really good idea. Something like "If you attach a vibrating device to a patient, this will reduce rigidity". That's why I mentioned Haas' research.