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Mild cognitive impairment disrupts attention network connectivity in Parkinson's disease: A combined multimodal MRI
Ondrej Bezdicek1, Tommaso Ballarini2, Filip Růžička1
1Department of Neurology and Centre of Clinical Neuroscience, First Faculty of Medicine and General University Hospital in Prague, Charles University, Czech Republic.
Abstract:
Mild cognitive impairment (MCI) affects approximately one-third of non-demented Parkinson's Disease (PD) patients. We aimed at investigating the neural correlates of MCI in PD combining multimodal magnetic resonance imaging (MRI) with large-scale data from the literature. We analyzed 31 PD patients and 30 matched controls. The standard neuropsychological assessment of PD-MCI covered memory, attention, executive functions, language and visuospatial abilities. Following validated criteria, 16 patients were classified as showing MCI. Whole-brain functional connectivity and structural volume changes were assessed, respectively, by means of eigenvector centrality (EC) and voxel-based morphometry. To address the involvement of specific functional brain networks, we validated our results by building a meta-analytic co-activation map (MACM) based on the previous literature and then testing its overlap with the parcellation of functional networks derived from 1000 healthy controls. The EC comparison between PD with normal cognition and controls showed a selective decline in interconnectedness in the bilateral lentiform nuclei. Differently, comparing PD with MCI and controls revealed additional changes in non-motor areas. Directly comparing PD with and without MCI, we found a reduced interconnectedness in the bilateral superior parietal lobules and precuneus. No differences in brain volume were detected comparing these patient groups. The MACM and overlap analyses showed that the observed connectivity changes were localized in the hubs of the dorsal attention network. Notably, this aligned with the predominant attention deficit observed in our sample. Overall, functional impairment in the dorsal attention network seems to be the hallmark of MCI due to PD, thus extending previous findings of brain connectivity disruption in non-motor networks.
Insights
Mild cognitive impairment (MCI) in Parkinson's Disease (PD) is linked to impaired connectivity in the dorsal attention network. This study used MRI and literature data to identify these neural changes, highlighting attention deficits as a key feature.
Area of Science:
- Neuroscience
- Neurology
- Radiology
Background:
- Mild cognitive impairment (MCI) affects about one-third of non-demented Parkinson's Disease (PD) patients.
- Understanding the neural basis of PD-MCI is crucial for early diagnosis and intervention.
Purpose of the Study:
- To investigate the neural correlates of MCI in PD using multimodal magnetic resonance imaging (MRI) and meta-analytic data.
- To identify specific brain regions and functional networks affected in PD-MCI.
Main Methods:
- Analysis of functional connectivity (eigenvector centrality) and structural volume (voxel-based morphometry) in 31 PD patients and 30 controls.
- Meta-analytic co-activation mapping (MACM) to validate findings against functional brain networks.
- Neuropsychological assessment of cognitive functions including memory, attention, and executive functions.
Main Results:
- PD patients with MCI showed reduced functional connectivity in the bilateral superior parietal lobules and precuneus compared to PD patients without MCI.
- Connectivity changes were localized within the hubs of the dorsal attention network.
- No significant differences in brain volume were detected between PD groups.
Conclusions:
- Functional impairment in the dorsal attention network is a hallmark of MCI in Parkinson's Disease.
- These findings extend previous research on brain connectivity disruptions in non-motor networks in PD.
- Attention deficits are a predominant cognitive symptom associated with these connectivity changes.