A new study is moving toward predicting who will get Parkinson's disease and predicting its course of progression. The study examined the spinal fluid of dozens of people who have the disease and those who don't. It found subtle differences between the levels of certain proteins known to be involved in the disease. It also found a different pattern of proteins in people with the most physically debilitating form of Parkinson's. It suggests for the first time that there may be different types of disease with different potential treatments. The research is found in the journal "JAMA Neurology."