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Precuneus Dysfunction in Parkinson's Disease With Mild Cognitive Impairment
Xiuqin Jia1,2, Ying Li3, Kuncheng Li3,4
1State Key Laboratory of Brain and Cognitive Science, Institute of Psychology, Chinese Academy of Sciences, Beijing, China.
Abstract:
Background: Mild cognitive impairment (MCI) frequently occurs in Parkinson's disease (PD). Neurovascular changes interact with neurodegenerative processes in PD. However, the deficits of cerebral blood flow (CBF) perfusion and the associated functional connectivity (FC) in PD patients with MCI (PD-MCI) remain unclear. Purpose: This study aimed to explore the specific neurovascular perfusion alterations in PD-MCI compared to PD with normal cognition (PD-NC) and healthy controls (HCs), and to further examine the resultant whole brain FC changes in the abnormal perfusion regions. Methods: Relative CBF (rCBF) was calculated using arterial spin labeling (ASL) in 54 patients with PD (27 patients with PD-NC and 27 patients with PD-MCI) and 25 HCs matched for age and gender ratio, who also underwent the structural MRI, resting-state functional MRI (rs-fMRI) and neuropsychological examinations. The gray matter (GM) changes in PD patients were analyzed using voxel-based morphometry (VBM). The alterations in rCBF perfusion and FC among groups were then analyzed respectively. Additionally, correlations between these alterations and neuropsychological performances were further examined. Results: Compared to HC, left caudate atrophy was detected in patients with PD. In comparison to both PD-NC and HC, patients with PD-MCI specifically exhibited hypoperfusion in the parietal memory network (PMN) in the precuneus (PCu) and decreased PCu-FC in the right striatum. Moreover, PCu perfusion and PCu-FC strengths in the right striatum were positively associated with memory performance in PD-MCI. Conclusions: These findings suggest that the posterior PMN dysfunction underlies memory deficits in PD-MCI.
Insights
Parkinson's disease patients with mild cognitive impairment show reduced blood flow and connectivity in the precuneus, impacting memory. This posterior parietal memory network dysfunction is key to their cognitive deficits.
Area of Science:
- Neuroscience
- Neurology
- Radiology
Background:
- Mild cognitive impairment (MCI) is common in Parkinson's disease (PD).
- Neurovascular changes and neurodegeneration interact in PD.
- Cerebral blood flow (CBF) and functional connectivity (FC) deficits in PD with MCI (PD-MCI) are not well understood.
Purpose of the Study:
- To investigate neurovascular perfusion and FC alterations in PD-MCI versus PD with normal cognition (PD-NC) and healthy controls (HCs).
- To examine whole-brain FC changes linked to abnormal perfusion regions in PD-MCI.
Main Methods:
- Arterial spin labeling (ASL) MRI to measure relative CBF (rCBF).
- Resting-state fMRI (rs-fMRI) for FC analysis.
- Voxel-based morphometry (VBM) for gray matter changes.
- Neuropsychological testing was performed on 54 PD patients (27 PD-NC, 27 PD-MCI) and 25 HCs.
Main Results:
- Left caudate atrophy observed in PD patients compared to HCs.
- PD-MCI patients showed specific hypoperfusion in the precuneus (PCu) within the parietal memory network (PMN) compared to PD-NC and HCs.
- Decreased PCu-FC in the right striatum was found in PD-MCI.
- PCu perfusion and right striatum PCu-FC positively correlated with memory performance in PD-MCI.
Conclusions:
- Posterior parietal memory network (PMN) dysfunction contributes to memory deficits in PD-MCI.
- Neurovascular alterations in the precuneus are specifically associated with cognitive impairment in Parkinson's disease.