To Sergey Brin and all others that fear for Parkinson: only if you forget what others told you and look at the work of Dr Dale Bredesen, you can open your eyes for new ways to cure brain diseases.
In a recent presentation, https://www.youtube.com/watch?v=SzCXyjy3BRo Dr Perlmutter and Dr Bredesen talk about a real cure for Alzheimer and hint that they think that they can do the same for Parkinson.
More info at http://www.impactaging.com/papers/v6/n9/full/100690.html (9 out of 10 patients cured!) and http://www.drperlmutter.com/learn/studies/