Philip, In my "lay" opinion, I understand Parkinson's Syndrome is used very loosely when a diagnosis is uncertain, when it could be something like PD but of the "Parkinson's Plus" variety. Often it is the GP who gives the "syndrome" tag when he/she doesn't want to scare the person with the name of PD. It is a little like being a bit pregnant... Then again, there are those groups who don't like PD being called a "disease" and call it a "syndrome." It may turn out that those who begin with a Parkinson's "Syndrome" diagnosis turn out to have PSP or MSA -- or just plain old PD with all its versions. Some study from the UK showed that approx 20 percent of diagnoses of PD are incorrect - but one can only be sure after death and the brain is studied. Does this help? I may be wrong. Sincerely Joy Graham