Abstract: Based on data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS), this study examines the decline of cognitive functions among the Chinese oldest-old born in 1899-1908, 1909-1918 and 1919-1928 using hierarchical linear model (HLM). As one ages, his/her cognitive functions continuously decrease, and such decrease accelerates before death. There are significant cohort differences in the decline trajectories of cognitive functions among the oldest-old. For the later-born cohorts with longer life expectancy, the decline of cognitive functions is delayed, and they also have better cognitive functions than the earlierborn. However, the later-born cohorts experience longer periods of cognitive impairments before death. Besides, there is strong heterogeneity in older people, and those with better socioeconomic environments, healthier states, and more active behavioral patterns have better cognitive performance.

Keywords:  Oldest-old, Cognitive Function, Decline Trajectory, Cohort Difference

摘要： 基于中国老龄健康长寿影响因素调查（CLHLS）数据，利用混合效应的多层线性模型，分析了1899~1908、1909~1918及1919~1928年3个出生队列的高龄老年人的认知能力衰退过程。研究发现，高龄老年人的认知能力随着年龄持续降低，在临终前会出现加速衰退趋势。3个队列人群的认知能力衰退轨迹存在显著的队列差异，随着预期寿命的增加，高龄老年人的认知能力衰退进程不断延迟，较晚的出生队列的认知能力优于较早的出生队列。但是，对老年人临终前的认知能力变化的分析发现，较晚出生的队列人群临终前处于认知能力缺损状态的时间更长。此外，老年人的认知能力存在强烈的异质性，具有良好的社会经济环境、健康状态及活跃的行为方式的老年人在认知能力上的表现更佳。

关键词: 高龄老年人, 认知能力, 衰退轨迹, 队列差异