The Role of Cerebrovascular Disease in Parkinson’s Disease Related Cognitive Impairment

With the high prevalence rate of mild cognitive impairment (MCI) and dementia in Parkinson's disease (PD), there is an increasing need to establish biomarkers that could identify those at risk of dementia. Small vessel cerebrovascular disease (SVD), including white matter hyperintensities (WMH), lacunes, perivascular spaces (PVS), and microbleeds, has been associated with the motor functions and cognitive impairment in PD. This suggests that SVD could be one of the mechanisms underlying the pathophysiological alterations that occur in the course of PD. Despite its importance, there is a paucity of literature and a lack of consensus in findings on SVD in PD. Without a clear understanding of the interaction between SVD and PD, patient management and care could be compromised. As such, this review summarizes the findings from current literature of SVD in PD, highlighting the limitations that could drive the heterogeneity in results. We also examine the role of other factors, such as microinfarcts and genetics, in their associations with SVD and motor-cognition in PD. Lastly, we discuss the role of optimizing vascular risk factors and the role of antiplatelets in managing patients with concomitant SVD and PD. Consensus on the definition of what constitutes the individual markers of SVD is imperative to determine the method of standardized imaging strategies and for better care management for patients with concomitant SVD and PD.