I found an article about Parkinson's and diet. Apparently an Atkins-like diet reduces symptoms. I believe this is due to the gluten restriction, not the ketogenic effect. Similar results have been found with Narcolepsy.

Article about study:
Ketone diet could help in Parkinson's
http://findarticles.com/p/articles/m...7/ai_n13595718

Study abstract:
Treatment of Parkinson disease with diet-induced hyperketonemia
http://www.neurology.org/cgi/content/abstract/64/4/728