Plasma total tau predicts executive dysfunction in Parkinson's disease

Area of Science:

• Neuroscience
• Biomarker Research
• Neurology

Background:

• Cognitive impairment is a significant non-motor symptom in Parkinson's disease (PD).
• Amyloid-beta and tau pathologies, known in Alzheimer's disease, can coexist with PD's synucleinopathy.
• Plasma levels of key biomarkers and their association with specific cognitive domains in PD require further investigation.

Purpose of the Study:

• To compare motor severity and cognitive assessments in PD patients.
• To analyze plasma levels of alpha-synuclein (α-syn), amyloid-beta 42 (Aβ42), and total tau (t-tau).
• To determine the relationship between these plasma biomarkers and specific cognitive functions in PD.

Main Methods:

• Plasma biomarkers (α-syn, Aβ42, t-tau) were quantified using immunomagnetic reduction assay in 55 PD participants.
• Motor severity was assessed using the Unified Parkinson's Disease Rating Scale (UPDRS) part III.
• Comprehensive neuropsychological assessments evaluated general and specific cognitive domains.

Main Results:

• Plasma α-syn levels showed a negative correlation with UPDRS part III motor scores (r = -0.352, p = 0.008).
• Plasma t-tau levels were negatively correlated with digit span forward (r = -0.446, p = 0.001) and backward recall (r = -0.417, p = 0.002).
• No significant correlations were found between α-syn or Aβ42 levels and any neuropsychological test scores.

Conclusions:

• Lower plasma α-syn levels are associated with motor dysfunction in PD.
• Higher plasma t-tau levels correlate with impaired cognitive performance, especially in attention and executive functions.
• Plasma biomarkers may hold potential for predicting specific cognitive deficits in Parkinson's disease.