With the committee's permission, may I just ask a question following something that Dr. Duncan was asking?
Dr. Grimes, when you talked about diagnosing Parkinson's you made the comment--or did I hear it right?--that it was difficult to diagnose, that you're not quite sure it's Parkinson's. So if a patient goes to a doctor and the doctor says to them that they have Parkinson's, how does that square with what you just said? How does a doctor know for sure that someone has Parkinson's?