Bendayan R, Piccinin A M, Hofer S M, Cadar D, Johansson B, Muniz-Terrera G
MRC Unit for Lifelong Health and Ageing, University College of London, Faculty of Population Health Sciences, London, UK.
Department of Psychology, University of Victoria, Victoria, BC, Canada.
J Aging Res. 2017;2017:6210105. doi: 10.1155/2017/6210105. Epub 2017 May 29.
The aim of this study is to explore the pattern of change in multiple measures of cognitive abilities in a sample of oldest-old adults, comparing two different time metrics (chronological age and time to death) and therefore examining both underlying conceptual assumptions (age-related change and terminal decline). Moreover, the association with individual characteristics as sex, education, and dementia diagnosis was also examined. Measures of cognitive status (Mini-Mental State Examination and the Swedish Clock Test) and tests of crystallized (knowledge and synonyms), memory (verbal memory, nonverbal long-term memory, recognition and correspondence, and short-term memory), and visuospatial ability were included. The sample consisted of 671 older Swedish adult participants of the OCTO Twin Study. Linear mixed models with random coefficients were used to analyse change patterns and BIC indexes were used to compare models. Results showed that the time to death model was the best option in analyses of change in all the cognitive measures considered (except for the Information Test). A significant cognitive decline over time was found for all variables. Individuals diagnosed with dementia had lower scores at the study entrance and a faster decline. More educated individuals performed better in all the measures of cognition at study entry than those with poorer education, but no differences were found in the rate of change. Differences were found in age, sex, or time to death at baseline across the different measures. These results support the terminal decline hypothesis when compared to models assuming that cognitive changes are driven by normative aging processes.
本研究的目的是在高龄老年人样本中探索认知能力多项指标的变化模式，比较两种不同的时间指标（实际年龄和死亡时间），从而检验两个潜在的概念假设（与年龄相关的变化和临终衰退）。此外，还考察了与性别、教育程度和痴呆症诊断等个体特征的关联。纳入了认知状态测量（简易精神状态检查表和瑞典钟表测试）以及晶体智力（知识和同义词）、记忆（言语记忆、非言语长期记忆、识别与对应以及短期记忆）和视觉空间能力测试。样本包括671名参加OCTO双胞胎研究的瑞典老年成年参与者。使用具有随机系数的线性混合模型分析变化模式，并使用贝叶斯信息准则（BIC）指数比较模型。结果表明，在所有考虑的认知测量分析中（信息测试除外），死亡时间模型是最佳选择。所有变量均发现随时间有显著的认知衰退。被诊断患有痴呆症的个体在研究开始时得分较低且衰退更快。受教育程度较高的个体在研究开始时的所有认知测量中表现均优于受教育程度较低者，但在变化率方面未发现差异。在不同测量的基线年龄、性别或死亡时间方面存在差异。与假设认知变化由正常衰老过程驱动的模型相比，这些结果支持临终衰退假说。
