Cognitive disorders in Parkinson's disease: Confirmation of a spectrum of severity

Kathy Dujardin*, Anja J. H. Moonen, Helene Behal, Luc Defebvre, Alain Duhamel, Annelien A. Duits, Lucie Plornhause, Celine Tard, Albert F. G. Leentjens

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

33 Citations (Web of Science)


Introduction: Clinical presentation and progression of cognitive disorders in Parkinson's disease (PD) is heterogeneous. Our objective was to confirm prospectively a previous exploratory cluster analysis based on retrospective data that identified five cognitive phenotypes in PD. Methods: A model-based confirmatory cluster analysis was conducted on the results of neuropsychological tests administered in 156 PD patients from two European movement disorder centers (Lille, n = 81; Maastricht, n = 75). The number of clusters was determined on the basis of statistical criteria as well as clinical plausibility. A factorial discriminant analysis assessed the quality of the clusters' separation. Results: A five-cluster model was statistically superior and clinically the most relevant. These clusters can be described as follows: I) cognitively intact patients with high level of performance in all cognitive domains (25.64%), 2) cognitively intact patients slightly slower than those in cluster 1 (26.92%), 3) patients with deficits in executive functions (37.18%), 4) patients with severe deficits in all cognitive domains, particularly executive functions (3.20%), 5) patients with severe deficits in all cognitive domains, particularly working memory and recall in verbal episodic memory (7.05%). The groups differed in terms of age, apathy and frequency of hallucinations that were all higher in the clusters with cognitive deficits, and the duration of formal education was lower in those groups. Conclusion: We confirm our previous exploratory analysis. Cognitive disorders in PD patients are heterogeneous and can be separated in five clusters ranging from patients with performance in the normal range to patients with severe disorders in all cognitive domains.
Original languageEnglish
Pages (from-to)1299-1305
JournalParkinsonism & Related Disorders
Issue number11
Publication statusPublished - Nov 2015


  • Cognition
  • Behavior
  • Dementia
  • Cluster analysis

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