If you were at the Parkinson's UK research conference last year you may have seen the top 10 research priorities project presentation. The project has recently been published in the British Medical Journal. There is more detail on this website at the following page.
I think this is a really powerful piece of research. It represents the voice of many many people affected by Parkinson's expressed in a robust research context. You can read a summary of the work on this site and, even better, the published paper is available to read too. It is a fantastic read.