Parkinson disease-associated cognitive impairment

Parkinson disease (PD) is the second most common neurodegenerative disorder, affecting >1% of population ?65 years age and with a prevalence set to double by 2030. In addition defining motor symptoms PD, multiple non-motor occur; among them, cognitive impairment can potentially occur at any stage. Cognitive decline usually slow insidious, but rapid in some cases. Recently, focus has been on early changes, where executive visuospatial impairments are typical be accompanied memory impairment, increasing risk for progression dementia. Other factors dementia include visual hallucinations, older biomarker changes such as cortical atrophy, well Alzheimer-type functional imaging cerebrospinal fluid, slowing frequency variation EEG. However, mechanisms underlying PD remain largely unclear. Cortical involvement Lewy body pathologies key features, likely involved. Cholinesterase inhibition only high-level evidence-based treatment available, other pharmacological non-pharmacological strategies being tested. Challenges identification disease-modifying therapies finding biomarkers better predict identify patients high impairment. ranges severity. This Primer reviews epidemiology, pathophysiology, diagnosis describes effects patient quality life future outlook field.