A few months ago I posted my presentation about Parkinson's and a ketogenic lifestyle: youtube.com/watch?v=W7kT4Oo.... This presentation is in Dutch but you can use subtitles and then you can translate.
And now I recently saw this video (youtube.com/watch?v=b3CtpaG... by Nick Norwitz who completed his PhD on this topic, and here he gives a very good scientific substantiation for keto in Parkinson's under the title A Ketogenic Diet for Parkinson's Disease: Shaking Up the Science.