Thanks for those links jeffreyn - they are very interesting.

They remind me of a talk that I listened to at a conference a while ago. It was given by a guy from Cambridge with both a PhD and a medical doctorate.

He made the point that PD is not "one disease" in the same sense that cancer is not "one disease".

Rather, he argued that, although PD has some clinical signs in common, the underlying pathology may vary a lot between different people.

What I got from that is that "one size fits all" is not likely to be effective for different people with PD.