Abstract：
OBJECTIVE: The aim of the study was to investigate the factors that underpin neuropsychiatric symptoms and how they might evolve over time in people with Mild Cognitive Impairment (MCI) and Alzheimer\'s disease (AD) dementia.
BACKGROUND: Neuropsychiatric symptoms are psychiatric and behavioural manifestations that occur in people with AD. These are highly prevalent along the continuum of the disease, including at the stage of MCI, as well as before cognitive decline. Various small- and large-scale projects have investigated the underlying factors that underpin these symptoms; however, the identification of clear clusters is still a matter of debate; furthermore, no study has investigated how the clusters might change across the development of AD pathology by comparing different time points.
OBJECTIVE: Our objective was to investigate the factors that underpin neuropsychiatric symptoms in Alzheimer\'s disease (AD) and Mild Cognitive Impairment (MCI) and to assess how the loadings might differ based on considerations such as the disease stage of the samples.
METHODS: Data was obtained from the Alzheimer\'s Disease Neuroimaging Initiative database (adni. loni.usc.edu), using scores from the Neuropsychiatric Inventory, followed up yearly from baseline until month 72. Participant groups included those with MCI or AD dementia, or a mixture of both, with all participants presenting with at least one neuropsychiatric symptom. A series of exploratory Principal Component and Factor (Principal Axis) Analyses were performed using Direct Oblimin rotation.
RESULTS: The best-fitting structure was interpreted for each time point. A consistent, unique structure could not be identified, as the factors were unstable over time, both within the MCI and AD groups. However, some symptoms showed a tendency to load on the same factors across most measurements (i.e., agitation with irritability, depression with anxiety, elation with disinhibition, delusions with hallucinations).
CONCLUSIONS: Although the analyses revealed some degree of co-occurrence of neuropsychiatric symptoms across time points/samples, there was also considerable variation. In the AD group, more discrete syndromes were evident at the early time points, whereas a more complex picture of co-occurring symptoms, with differences likely reflecting disease staging, was seen at later time points. As a clear and distinctive factor structure was not consistently identified across time points/ samples, this highlights the potential importance of sample selection (e.g., disease stage and/or heterogeneity) when studying, for example, the neurobiological underpinnings of neuropsychiatric symptoms.
BACKGROUND: Neuropsychiatric symptoms are psychiatric and behavioural manifestations that occur in people with AD. These are highly prevalent along the continuum of the disease, including at the stage of MCI, as well as before cognitive decline. Various small- and large-scale projects have investigated the underlying factors that underpin these symptoms; however, the identification of clear clusters is still a matter of debate; furthermore, no study has investigated how the clusters might change across the development of AD pathology by comparing different time points.
OBJECTIVE: Our objective was to investigate the factors that underpin neuropsychiatric symptoms in Alzheimer\'s disease (AD) and Mild Cognitive Impairment (MCI) and to assess how the loadings might differ based on considerations such as the disease stage of the samples.
METHODS: Data was obtained from the Alzheimer\'s Disease Neuroimaging Initiative database (adni. loni.usc.edu), using scores from the Neuropsychiatric Inventory, followed up yearly from baseline until month 72. Participant groups included those with MCI or AD dementia, or a mixture of both, with all participants presenting with at least one neuropsychiatric symptom. A series of exploratory Principal Component and Factor (Principal Axis) Analyses were performed using Direct Oblimin rotation.
RESULTS: The best-fitting structure was interpreted for each time point. A consistent, unique structure could not be identified, as the factors were unstable over time, both within the MCI and AD groups. However, some symptoms showed a tendency to load on the same factors across most measurements (i.e., agitation with irritability, depression with anxiety, elation with disinhibition, delusions with hallucinations).
CONCLUSIONS: Although the analyses revealed some degree of co-occurrence of neuropsychiatric symptoms across time points/samples, there was also considerable variation. In the AD group, more discrete syndromes were evident at the early time points, whereas a more complex picture of co-occurring symptoms, with differences likely reflecting disease staging, was seen at later time points. As a clear and distinctive factor structure was not consistently identified across time points/ samples, this highlights the potential importance of sample selection (e.g., disease stage and/or heterogeneity) when studying, for example, the neurobiological underpinnings of neuropsychiatric symptoms.
摘要：
目的：本研究的目的是调查轻度认知障碍（MCI）和阿尔茨海默病（AD）痴呆患者神经精神症状的影响因素，以及它们如何随时间演变。
背景：神经精神症状是发生在AD患者中的精神和行为表现。这些在疾病的连续过程中非常普遍，包括在MCI阶段以及认知能力下降之前。各种小型和大型项目已经调查了支撑这些症状的潜在因素；然而，明确的集群的确定仍然是一个有争议的问题；此外，没有研究通过比较不同的时间点来研究在AD病理发展过程中集群可能如何变化.
目的：我们的目的是调查阿尔茨海默病（AD）和轻度认知障碍（MCI）中神经精神症状的基础因素，并根据样品的疾病阶段等因素评估负荷可能有所不同。
方法：数据来自阿尔茨海默病神经影像学计划数据库（adni.Loni.usc.edu),使用神经精神量表的分数，从基线到72个月，每年随访一次。参与者组包括MCI或AD痴呆症患者，或者两者的混合物，所有参与者都表现出至少一种神经精神症状。使用直接Oblimin旋转进行一系列探索性主成分和因子(主轴)分析。
结果：解释了每个时间点的最佳拟合结构。一个一致的，无法识别独特的结构，随着时间的推移，这些因素是不稳定的，在MCI和AD组中。然而,一些症状表明，在大多数测量中，倾向于加载相同的因素(即，烦躁不安，抑郁和焦虑，兴奋与抑制，带有幻觉的妄想）。
结论：尽管分析揭示了不同时间点/样本的神经精神症状在一定程度上同时出现，也有相当大的差异。在AD组中,在早期时间点更明显的离散综合征，而同时出现的症状更复杂，差异可能反映疾病分期，在稍后的时间点看到。由于在时间点/样本中没有一致地识别出清晰而独特的因子结构，这凸显了样本选择的潜在重要性(例如，疾病阶段和/或异质性)在研究时，例如,神经精神症状的神经生物学基础。
背景：神经精神症状是发生在AD患者中的精神和行为表现。这些在疾病的连续过程中非常普遍，包括在MCI阶段以及认知能力下降之前。各种小型和大型项目已经调查了支撑这些症状的潜在因素；然而，明确的集群的确定仍然是一个有争议的问题；此外，没有研究通过比较不同的时间点来研究在AD病理发展过程中集群可能如何变化.
目的：我们的目的是调查阿尔茨海默病（AD）和轻度认知障碍（MCI）中神经精神症状的基础因素，并根据样品的疾病阶段等因素评估负荷可能有所不同。
方法：数据来自阿尔茨海默病神经影像学计划数据库（adni.Loni.usc.edu),使用神经精神量表的分数，从基线到72个月，每年随访一次。参与者组包括MCI或AD痴呆症患者，或者两者的混合物，所有参与者都表现出至少一种神经精神症状。使用直接Oblimin旋转进行一系列探索性主成分和因子(主轴)分析。
结果：解释了每个时间点的最佳拟合结构。一个一致的，无法识别独特的结构，随着时间的推移，这些因素是不稳定的，在MCI和AD组中。然而,一些症状表明，在大多数测量中，倾向于加载相同的因素(即，烦躁不安，抑郁和焦虑，兴奋与抑制，带有幻觉的妄想）。
结论：尽管分析揭示了不同时间点/样本的神经精神症状在一定程度上同时出现，也有相当大的差异。在AD组中,在早期时间点更明显的离散综合征，而同时出现的症状更复杂，差异可能反映疾病分期，在稍后的时间点看到。由于在时间点/样本中没有一致地识别出清晰而独特的因子结构，这凸显了样本选择的潜在重要性(例如，疾病阶段和/或异质性)在研究时，例如,神经精神症状的神经生物学基础。
