Abstract
Mild cognitive changes, including executive dysfunction, are seen in Parkinson’s Disease (PD). Approximately 30% of individuals with PD develop Parkinson’s disease dementia (PDD). Mild cognitive impairment (MCI) has been identified as a transitional state between normal cognition and dementia. Although PD-MCI and its cognitive correlates have been increasingly studied as a risk indicator for development of PDD, investigations into the PD-MCI construct have yielded heterogeneous findings. Thus, a typical PD-MCI cognitive profile remains undefined. The present meta-analysis examined published cross-sectional studies of PD-MCI and cognitively normal PD (PD-CN) groups to provide aggregated effect sizes of group test performance by cognitive domain. Subsequently, longitudinal studies examining PD-MCI to PDD progression were meta-analyzed. Ninety-two cross-sectional articles of PD-MCI vs. PD-CN were included; 5 longitudinal studies of PD-MCI conversion to PDD were included. Random effects meta-analytic models were constructed resulting in effect sizes (Hedges’ g) for cognitive domains. Overall performance across all measures produced a large effect size (g = 0.83, 95% CI [0.79, 0.86], t2 = 0.18) in cross-sectional analyses, with cognitive screeners producing the largest effect (g = 1.09, 95% CI [1.00, 1.17], t2 = 0.19). Longitudinally, overall measures produced a moderate effect (g = 0.47, 95% CI [0.40, 0.53], t2 = 0.01), with measures of executive functioning exhibiting the largest effect (g = 0.70, 95% CI [0.51, 0.89], t2 = 0.01). Longitudinal effects were made more robust by low heterogeneity. This report provides the first comprehensive meta-analysis of PD-MCI cognitive outcomes and predictors in PD-MCI conversion to PDD. Limitations include heterogeneity of cross-sectional effect sizes and the potential impact of small-study effects. Areas for continued research include visuospatial skills and visual memory in PD-MCI and longitudinal examination of executive dysfunction in PD-MCI.
Original language | English |
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Pages (from-to) | 149-160 |
Number of pages | 12 |
Journal | Neuropsychology Review |
Volume | 32 |
Issue number | 1 |
DOIs | |
State | Published - Mar 2022 |
Bibliographical note
Publisher Copyright:© 2021, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
Keywords
- Cognition
- Dementia
- Mild cognitive impairment
- Parkinson’s disease
ASJC Scopus subject areas
- Neuropsychology and Physiological Psychology