033-22 – Structural brain alterations in prodromal Parkinson's Disease

The neurodegenerative Parkinson’s disease (PD) is characterised by motor disturbances caused by neuronal damage in the substantia nigra. However, years before the onset of motor symptoms, in its prodromal stages, PD presents autonomic symptoms such as sleep disturbances. REM-sleep behavioural disorder (RBD) is a risk factor for PD, and a possible biomarker for its prodromal stage. This Voxel-Based Morphometry study examined structural changes in the brain grey matter and white mater, comparing participants with RBD who are in prodromal stages of PD, patients with newly diagnosed PD, and healthy controls. We report cerebellar grey matter increase in patients with PD in the motor areas, which is thought to be related to possible motor compensatory mechanisms accompanying early processes of diagnosed PD. These possibly compensatory mechanisms would be communicated between the cerebellum and basal ganglia. We also report increased grey matter in the inferior and middle temporal gyri in patients with PD, but decreased grey matter in the prodromal-RBD cohort, when compared to healthy controls and to each other. These structural changes could be related to various cognitive processes, and possibly linked to PD-related cognitive decline. Further areas are also discussed. Further characterising the neuropathological effects of RBD might help identifying prodromal PD subjects with more specificity and sensitivity. Earlier confirmation of PD could lead to earlier intervention, and therefore more efficient management of PD progression.