Robert,
I don't know much about hospitals and clinics in Illinois. However in Toledo Ohio there is the Medical University of Ohio (I'm not sure if the name is correct, they recently changed it). Dr.Larry Elmer is the director of the movement disorder clinic. He's a super guy and very very knowledgeable about PD. He talks about PD in terms you can understand. If you have a question he's more than happy to explain in a way that you will understand.
Then there is the Cleveland Clinic. From my experience there, they will find what your problem is. The doctor I saw there has since retired so I really can't comment on or suggest any of the doctors there. One thing I do know is they are good or they wouldn't be employed by the Cleveland Clinic.
I think the trick to getting the best care for yourself is finding a knowledgeable doctor you can talk with whether it's at the Mayo Clinic or your hometown hospital.

GregD