Background: Cognitive impairment is a disabling non-motor symptom of Parkinson's disease (PD). It remains uncertain whether declines in specific cognitive domains relate to imaging or plasma biomarkers across the disease continuum.
Objective: We investigated whether neuroimaging and plasma biomarkers correlate with individual task-specific cognitive domain declines evidenced by computerized neuropsychological tests in PD patients.
Methods: A total of 107 participants, including 87 PD patients (30 with normal cognition [PD-NC], 30 with mild cognitive impairment [PD-MCI], 27 with dementia [PDD]), and 20 healthy controls, were recruited. All received the Cambridge Neuropsychological Test Automatic Battery (CANTAB) test, brain MRI, and assays of plasma biomarkers, including α-synuclein, tau, Aβ42, and Aβ40.
Results: PD patients had generally poorer cognitive performance than controls. Patients with PD-MCI and PDD had worse performance in visual, verbal, and working memory and executive function than those with PD-NC. After adjusting for covariates, PDD patients had global cortical thinning, especially in the temporal and parietal lobes, and higher plasma α-synuclein levels and tau:Aβ42 ratios than PD-NC group. Plasma α-synuclein level was associated with frontal lobe-mediated tasks, while the tau:Aβ42 ratio was associated with posterior cortical-mediated tasks. Facial emotion recognition tasks and visual pattern recognition associated with frontotemporal cortical thinning. The accuracy of predicting PDD using age alone (area under the curve [AUC] 0.756) increased by incorporating plasma biomarkers (AUC = 0.851, p = 0.025).
Conclusions: Cognitive decline in PD patients has a task-specific correlation with neuroimaging and plasma biomarkers, which may implicate the underlying neuropathological process of PDD.
Keywords: Biomarkers; CANTAB; Cognition; Parkinson’s disease; Plasma.
© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.