Abstract: Cognitive impairment is a particularly severe non-motor symptom of Parkinson’s disease that significantly diminishes the quality of life of affected individuals. Identifying reliable biomarkers for cognitive impairment in Parkinson’s disease is essential for early diagnosis, prognostic assessments, and the development of targeted therapies. This review aims to summarize recent advancements in biofluid biomarkers for cognitive impairment in Parkinson’s disease, focusing on the detection of specific proteins, metabolites, and other biomarkers in blood, cerebrospinal fluid, and saliva. These biomarkers can shed light on the multifaceted etiology of cognitive impairment in Parkinson’s disease, which includes protein misfolding, neurodegeneration, inflammation, and oxidative stress. The integration of biofluid biomarkers with neuroimaging and clinical data can facilitate the development of predictive models to enhance early diagnosis and monitor the progression of cognitive impairment in patients with Parkinson’s disease. This comprehensive approach can improve the existing understanding of the mechanisms driving cognitive decline and support the development of targeted therapeutic strategies aimed at modifying the course of cognitive impairment in Parkinson’s disease. Despite the promise of these biomarkers in characterizing the mechanisms underlying cognitive decline in Parkinson’s disease, further research is necessary to validate their clinical utility and establish a standardized framework for early detection and monitoring of cognitive impairment in Parkinson’s disease.

Key words: amyloid-β, biomarkers, cognitive impairment, dementia, metabolomics, neurodegeneration, neuroinflammation, Parkinson’s disease, proteomics, tau, α-synuclein