Redefining Efficacy in Parkinson’s Disease—Early Motor Phase Treatments and the Potential for Treating during the Pre-motor Phase

Until recently, Parkinson’s disease (PD) treatments have overwhelmingly focused on motor rather than non-motor symptoms. Early and accurate detection of PD is considered desirable, with major research initiatives presently focused upon identifying and validating clinical batteries and biomarkers to this end. This raises the question of how the patient deemed at high risk of developing PD should be counseled and treated. Currently there are no approved treatments for pre-motor PD, and thus any pre-motor complaints are treated for specific symptom relief, such as for sleep or mood disorders. For individuals known to be at risk, for example non-manifesting gene carriers, there is likewise a lack of consensus on management, and no proven means of risk reduction. Here we examine options for early PD treatment and clinical evidence for disease modification that might favor ‘pushing back’ treatment to the pre-motor stage.