Very interesting. I "diagnosed" (not a doctor) my father's early-stage Parkinson's a few years back when I went home for the holidays and noticed a resting tremor in the classic "pill-rolling" motion. No one had mentioned anything to him about it and a resting tremor is unlikely to be noticed by the sufferer.

I got him to see a neurologist, whose more accurate and professional testing confirmed my concerns. But this looks like a great early-warning system.