Parkinson's, where are we heading?

The prevalence of Parkinson's disease has rapidly increased over the last decade. This editorial discusses our current understanding of the pathophysiological basis for the condition, with a particular focus on the potential role of α-synuclein, and the consequent implications this has for both the development of new investigations and disease-modifying therapies. Specifically, the article discusses the development of a new diagnostic test for cerebrospinal fluid α-synuclein, the development of a new staging system for Parkinson's disease, which takes into account the α-synuclein, genetic and neuro-imaging status, and the results of two recently completed clinical trials, using monoclonal antibodies wherein α-synuclein is the principal target. We also discuss the increasing awareness of the importance of non-motor symptoms in Parkinson's disease including hyposmia, rapid eye movement sleep behaviour disorder, and autonomic and cognitive symptoms.