I agree with everything Soccermum said, and add the following:

When you see your MDS, recognize that although she knows far more about PD than you, you will always know more about your own body than her. As a result, I believe it makes most sense to consider your MDS as a provider of advice, from which you yourself will ultimately make decisions (about medications, diet, exercise, and so on). I think it works better that way than treating the MDS as a kind of "answer oracle" who tells you what to do.

Bottom line: The MDS can help you figure out how to treat your disease. If you simply "let her treat it for you", it won't work nearly as well, because she doesn't have access to knowledge about your body in nearly as much detail as you.

Dan