 In this study we now time 2 examine 25 PD patients who where diagnosed as having PD and who underwent FP-CIT-SPECT in the years 2003 up to 2006 time 1. At both times - time 1 and time 2 - the part III motor part of the Unified Parkinson s Disease Rating Score UPDRS-Score was will be performed in the Off state. Furthermore, at time 2 the CERAD examination will be performed. 25 patients have to be included, if a correlation coefficient r 0.5, an error 1st order 0.05 and an error 2nd order 0.20 are assumed. 