Identifying subtypes of mild cognitive impairment in Parkinson's disease using cluster analysis
Dana Pourzinal1,2, Ji Hyun J Yang1, Gerard J Byrne1,3
1UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Royal Brisbane and Women's Hospital, Building 71/918, Herston, Brisbane, QLD, 4029, Australia.
Introduction:
The concept of Mild Cognitive Impairment (MCI) in Parkinson's disease (PD) has shown the potential for identifying at-risk dementia patients. Identifying subtypes of MCI is likely to assist therapeutic discoveries and better clinical management of patients with PD (PWP). Recent cluster-based approaches have demonstrated dominance in memory and executive impairment in PD. The present study will further explore the role of memory and executive impairment and associated clinical features in non-demented PWP.
Method:
A K-means cluster analysis was performed on ten "frontal" and "posterior" cognitive variables derived from a dataset of 85 non-demented PWP. The resulting cluster structure was chosen based on quantitative, qualitative, theoretical, and clinical validity. Cluster profiles were then created through statistical analysis of cognitive and clinical/demographic variables. A descriptive analysis of each cluster's performance on a comprehensive PD-MCI diagnostic battery was also explored.
Results:
The resulting cluster structure revealed four distinct cognitive phenotypes: (1) frontal-dominant impairment; (2) posterior-cortical-dominant impairment; (3) global impairment, and (4) cognitively intact. Demographic profiling revealed significant differences in the age, gender split, global cognitive ability, and motor symptoms between these clusters. However, there were no significant differences between the clusters on measures of depression, apathy, and anxiety.
Conclusion:
These results validate the existence of distinct cognitive phenotypes within PD-MCI and encourage future research into their clinical trajectory and neuroimaging correlates.
Insights
Researchers identified four distinct cognitive subtypes in Parkinson's disease patients with mild cognitive impairment (PD-MCI), differentiating them by frontal, posterior, or global impairment, or cognitive intactness.
Area of Science:
- Neuroscience
- Neurology
- Cognitive Science
Background:
- Mild Cognitive Impairment (MCI) in Parkinson's disease (PD) is crucial for identifying dementia risk.
- Subtyping MCI in PD aids therapeutic development and patient management.
- Previous studies highlight memory and executive dysfunction in PD.
Purpose of the Study:
- To explore memory and executive impairment subtypes in non-demented PD patients.
- To identify associated clinical features within these cognitive subtypes.
Main Methods:
- K-means cluster analysis on cognitive variables from 85 non-demented PD patients.
- Validation of cluster structure based on multiple validity measures.
- Creation of cluster profiles using cognitive and clinical/demographic data.
Main Results:
- Four distinct cognitive phenotypes were identified: frontal-dominant, posterior-cortical-dominant, global impairment, and cognitively intact.
- Significant differences observed in age, gender, global cognition, and motor symptoms across clusters.
- No significant differences found in depression, apathy, or anxiety levels between clusters.
Conclusions:
- The study validates distinct cognitive phenotypes within PD-MCI.
- These findings support further research into the clinical progression and neuroimaging of these subtypes.
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