LAUSR

The pathological processes underlying Parkinson ’ s disease (PD) begin in the prodromal phase of the disease, which may well span more than 2 decades. 1,2 During that period, pathology spreads throughout the nervous sys-tem. 3 The most speci fi c prodromal feature of PD is the presence of rapid eye movement sleep behavior disorder (RBD). 4-6 When PD fi nally becomes clinically manifest, 60% to 80% of dopaminergic neurons in the nigrostriatal pathway are already depleted. 7 This advanced state of pathology likely explains why disease modi fi cation has proven to be dif fi cult in individuals with manifest PD. 7 Therefore, there in preventing or slowing the progression of PD at an earlier stage by targeting risk factors that drive the earliest pathological processes, that is, at a time when individuals have either no or only prodromal symptoms.