Cognitive decline in Parkinson's disease: the complex picture

Area of Science:

• Neuroscience
• Neurology
• Cognitive Science

Background:

• Mild cognitive impairment (PD-MCI) and dementia (PDD) are frequent non-motor symptoms in Parkinson's disease (PD).
• PD-MCI significantly increases the risk of developing dementia, with PDD prevalence reaching 80% after 15-20 years.
• Research aims to identify early dementia biomarkers and at-risk cognitive profiles for timely therapeutic intervention.

Purpose of the Study:

• To address the challenge of defining a comprehensive cognitive model for PDD due to heterogeneous deficits.
• To explore the role of neuroimaging and cognitive scales in identifying at-risk profiles for dementia in PD.
• To understand the interplay of neurodegenerative processes and brain network changes in PDD development.

Main Methods:

• Review of neuroimaging studies employing various methods and techniques.
• Analysis of evidence suggesting roles for beta-amyloid and tau deposition beyond dopaminergic degeneration.
• Consideration of specific cognitive scales for identifying high-risk profiles.

Main Results:

• Neuroimaging suggests that beta-amyloid and tau deposition, alongside dopaminergic degeneration, contribute to cognitive decline in PD.
• Specific cognitive scales may help identify individuals with a higher risk of developing dementia.
• Structural disconnection in brain networks is implicated in the development of dementia in PD.

Conclusions:

• A comprehensive cognitive model for PDD is challenging due to the diverse nature of cognitive deficits.
• Identifying early dementia biomarkers in PD requires integrating neuroimaging and cognitive assessments.
• Prospective studies are needed to elucidate the interplay of neurodegeneration, network changes, and dementia development in Parkinson's disease.