基于感觉运动与海马-皮层环路协同作用的八段锦对主观认知下降的效应机制研究

As the preclinical stage of Alzheimer's disease, subjective cognitive decline (SCD) is considered as a transition phase between the normal aging and the mild cognitive impairment and is also considered as the critical window treatment stage in preventing the cognitive decline. Previous studies have suggested that Baduanjin can prevent the cognitive decline, however, the underling mechanisms are unclear. Literatures showed that the structural and functional abnormalities of the Hippocampal-Cortex pathway play a key role in the pathogenesis of SCD. Based on the embodied cognition theory, the cognitive processing relies on the body's sensory motor system. In addition, previous studies have demonstrated that Baduanjin exercise can improve the sensory motor function of elders. Based on these, the study would propose a hypothesis that Baduanjin exercise improve the cognitive function of SCD may via the mechanisms as follows: 1) Baduanjin exercise improve the sensory motor function in patients with SCD; 2) the improvement of sensory motor function can modulate the Hippocampal-Cortex pathway; 3) then the remodeling of Hippocampal-Cortex pathway regulate the cognitive processing in SCD; 4) thus the cognitive function was improved in patients with SCD. In present study, we investigate the modulation effects of longitudinal Baduanjin exercise (24-week) on the cognitive function, sensory motor function and the structure / function of the Hippocampal-Cortex pathway in patients with SCD. In addition, we analysis the causality among the three changes (cognitive function, sensory motor function and the Hippocampal-Cortex pathway) using the structural equation modeling to investigate the underlying mechanisms of Baduanjin exercise in SCD. The conclusions will provide theoretical evidences for the clinical application of Baduanjin exercise in patients with SCD.

主观认知下降（SCD）被认为是介于正常老化和轻度认知障碍之间的状态，是阿尔茨海默病的临床前期，也是延缓及逆转认知功能恶化的关键窗口治疗期。研究表明中医传统功法八段锦可以延缓认知功能下降，但作用机制不清楚。中枢记忆系统海马-皮层环路结构/功能异常与SCD发病密切相关。具身认知理论认为认知加工依赖身体感觉运动系统。前期发现八段锦可以改善老年人的感觉运动功能。据此推测八段锦可能通过改善SCD患者肢体感觉运动功能从而调控与其发病相关的海马-皮层环路，该环路重塑影响了SCD患者认知加工模式，改善其认知功能。本项目拟观察24周八段锦运动对SCD患者认知功能干预效果，检测其对SCD患者肢体感觉运动功能及海马-皮层环路相关脑区结构和功能的影响。采用结构方程模型分析认知、感觉运动及海马-皮层环路改变之间的因果关系，探讨八段锦对SCD的效应机制。本研究结果将为八段锦干预SCD的临床推广应用提供理论依据。

主观认知下降（SCD）被认为是介于正常老化和轻度认知障碍之间的状态，是阿尔茨海默病的临床前期，也是延缓老年认知功能恶化的关键窗口治疗期，早期有效干预有助于认知功能下降的逆转。本项目采用随机对照设计，以有氧运动与无运动干预为对照，运用神经心理学量表评估八段锦训练对SCD的干预效果；同时，采集SCD患者干预前后感觉运动功能相关指标、多模态影像数据，探讨八段锦对SCD的效应机制。本研究发现：24周八段锦训练后，1）认知功能上，与无运动对照组相比，SCD患者整体认知功能阿尔茨海默病认知评价量表总分及单词回忆任务评分下降（认知功能改善）；华山版听觉词语学习测验长时延迟回忆评分提高，显著优于有氧运动和无运动对照组；与无运动对照相比，执行功能中连线测试题B时长缩短，差异具有统计学意义（P＜0.05）；2）肢体感觉运动功能上，与无运动对照组相比，SCD患者腰部侧屈肌力增加，6分钟步行试验距离增加、速度提高，差异具有统计学意义（P＜0.05）；3）脑影像学上，八段锦训练调控SCD患者壳核、海马旁回、尾状核、纹状体等脑区灰质体积，24周八段锦训练后，SCD患者楔前叶与颞下回、角回，内侧前额叶与双侧小脑、双背外侧前额叶皮层、中央前回及海马与右侧岛叶功能连接显著改变；4）相关、中介分析发现，SCD患者情景记忆-长时延迟回忆与腰部左侧屈肌力改变正相关，腰部侧屈肌力与楔前叶-左侧角回功能连接强度存在交互效应，表明海马-皮层环路关键脑区楔前叶与全脑功能连接改变在八段锦提高SCD患者腰部肌力，进而改善情景记忆-延迟回忆功能中可能具有调节作用。以上结果为八段锦干预SCD的临床推广应用提供了理论依据，对于减少老年认知下降对社会及家庭带来的负担具有潜在益处，具有较好的社会效应。