Approaches to the Diagnosis of Parkinson’s Disease during the Pre-motor Phase
Parkinsons disease (PD) remains a clinical diagnosis based primarily upon motor features of tremor, rigidity, and bradykinesia. However, by the time motor symptoms occur, the underlying pathology may be widespread. Approaches using a combination of clinical batteries and sophisticated biomarker technology now hold promise for identifying individuals earlier in the course of the disease, including those at risk of PD who may not yet have manifested any motor symptoms. Non-motor symptoms, such as specific sleep disorders, olfactory dysfunction, and autonomic changes, occur during a pre-motor phase, and their use in PD risk stratification is being actively evaluated. Neuroimaging techniques, in particular those focused upon measuring dopamine transporter density, are now in use in many specialist centers, molecular markers are in development and validation phases, and the use of genomic analyses has expanded the number of loci identified as contributing to PD risk. Identifying those at risk of developing PD will aid in the clinical management of the disease, and perhaps enable the use of disease-modifying drugs at as early a stage as possible.