Cognitive deficits in Parkinson's disease: current perspectives

Cognitive dysfunction is a common and significant non-motor symptom of Parkinson's disease (PD). PD mild cognitive impairment (PD-MCI) is evident in approximately one-quarter of patients at the time of PD diagnosis, and half of PD patients have progressed to PD dementia (PDD) after 10 years. The transition to PDD from PD-MCI is not linear and may depend on the facets of cognition affected. Despite increased understanding of pathological, neurotransmitter and genetic drivers, there are no proven pharmacological treatments for PD-MCI and those licensed for PDD are of modest benefit only. Biomarkers to predict those most at risk of developing PDD are under investigation and are likely to be essential so that early and individualized treatment can be provided.