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.

帕金森病 (PD) 中可见轻度认知变化，包括执行功能障碍。大约 30% 的 PD 患者会发展为帕金森病痴呆 (PDD)。轻度认知障碍（MCI）已被确定为正常认知和痴呆之间的过渡状态。尽管 PD-MCI 及其认知相关因素已越来越多地作为 PDD 发展的风险指标进行研究，但对 PD-MCI 结构的调查得出了不同的结果。因此，典型的 PD-MCI 认知特征仍未定义。本荟萃分析检查了已发表的 PD-MCI 和认知正常 PD (PD-CN) 组的横断面研究，以提供按认知领域的组测试表现的聚合效应大小。随后，对检验 PD-MCI 到 PDD 进展的纵向研究进行了荟萃分析。纳入了 PD-MCI 与 PD-CN 的 92 篇横断面文章；纳入了 5 项 PD-MCI 转化为 PDD 的纵向研究。构建随机效应元分析模型，得出效应大小（Hedges'g ) 用于认知领域。在横断面分析中，所有测量的总体表现产生了较大的影响大小 ( g = 0.83, 95% CI [0.79, 0.86], t ^{2 = 0.18)，认知筛查产生最大的影响 (} g = 1.09, 95% CI [1.00, 1.17], t ² = 0.19)。从纵向上看，总体测量产生了中等影响（g = 0.47, 95% CI [0.40, 0.53], t ² = 0.01），执行功能的测量表现出最大的影响（g = 0.70, 95% CI [0.51, 0.89] , t ²= 0.01)。低异质性使纵向效应更加稳健。本报告首次对 PD-MCI 认知结果和 PD-MCI 转化为 PDD 的预测因素进行综合荟萃分析。局限性包括横截面效应大小的异质性和小型研究效应的潜在影响。继续研究的领域包括 PD-MCI 中的视觉空间技能和视觉记忆以及 PD-MCI 中执行功能障碍的纵向检查。