Studying these folk would be incredibly difficult, as we would end up with a lot of data on the kind of people who are wealthy enough, sick enough, and desperate enough to undertake the procedure, with no real basis of comparison. Scientifically, they're not of much use.

Brownian Motion is a mathematical construct, which, among other things, is nowhere differentiable (almost surely). You can pin a BM down into sets with high probability, but no, you can't really predict it. It is merely used to *model* the movement of a particle in a fluid, it is not actually the process by which the molecules move. Indeed, "such a path represents the motion of a particle that in its wanderings back and forth travels an infinite distance in finite time. [BM] does not in its fine structure represent physical reality." (Billingsley, "Probability and Measure"). At least the science is interesting.