基于默认网络的八段锦运动干预轻度认知障碍的多模态影像学研究

Mild cognitive impairment (MCI) is a transition between normal aging and senile dementia. Its prevalence reached up to 20% in our country’s population with sixty years old and over, furthermore its five-year accumulating transformed rate of dementia could reach 60.5%, but the progression of dementia could be delayed even reversed to normal if the effective intervention was exerted in its early stage. Therefore, It is well-recognized optimal stage to effectively improve the cognitive ability of patients with MCI with regard to delaying the progression of senile dementia. Several systematic reviews have confirmed that aerobic exercises could improve the cognitive ability of patients with MCI, but it is not affirmative which type of aerobic exercise and how to improve the cognitive ability. As a body-mind aerobic exercise with the brilliance characteristics of Chinese medicine, our previous studies found that regular Baduanjin exercise could improve cognitive ability of general older population, and its neuromechanism might be associated with the changed structural and functional characteristics of default model network. However, It is unclear that the effect and its neuromechanism of Baduanjin intervention for MCI. In this study, a rigour randomized controlled trial will be design to validate the effectiveness of Baduanjin exercise for cognitive ability of patients with MCI. Meanwhile the changes of structure, activated state and functional connection of the relative brain region of default model network in patients with MCI will be detected by using fMRI. Combined with data of cognitive ability assessed by the rating scales, the mechanism of Baduanjin exercise improving cognitive ability of patients with MCI will be analyzed systematically. Their conclusions will provide practical and theoretical evidences for the application of Baduanjin exercise for patients with MCI.

轻度认知障碍（MCI）是老年性痴呆的临床前状态，在我国60岁以上人群中患病率为20%左右，5年痴呆累积转换率可达60.5%，但早期有效干预可延缓其进展甚至逆转为正常。虽然多篇系统综述的结果已证实有氧运动能够有效改善MCI患者的认知功能，但无法明确某种具体的有氧运动方式是否有效及其作用机制。我们前期研究发现，作为具有鲜明中医特色的调心调经、心身结合的有氧运动，规律性八段锦锻炼能够提高社区老年人的认知功能，其中枢神经机制与改变默认网络相关脑区的形态结构和功能有关，但对MCI患者的作用效果及其机制尚不清楚。本项目拟采用严格随机对照研究设计，以MCI患者为对象，观察规律性八段锦运动改善MCI患者认知功能的干预效果，并从默认网络角度，采用功能核磁技术检测其相关脑区形态结构、激活状态及功能连接的改变，综合分析八段锦运动改善MCI患者认知功能的中枢神经影像学机制，为其应用提供理论依据。

轻度认知障碍（MCI）是老年性痴呆的临床前状态，在我国60岁以上人群中患病率为20%左右，5年痴呆累积转换率可达60.5%，但早期有效干预可延缓其进展甚至逆转为正常。本项目采用严格的随机对照研究设计，以社区MCI患者为研究对象，系统观察八段锦运动改善MCI患者认知功能的干预效果并及与快步走进行比较。并从默认网络角度，综合分析八段锦运动改善MCI患者认知功能的中枢影像学机制。结果发现：①干预6个月后，相比于无运动干预组，八段锦组MCI患者整体认知功能MoCA评分平均提高3分（24.67±2.38 vs 21.66±3.37）; 相比于快步走组，八段锦组MCI患者整体认知功能MoCA评分平均提高1.79分（24.67±2.38 vs 22.88±3.16），差异均有显著的统计学意义（P＜0.001）。②对于分散注意力，干预后八段锦组听觉正确数明显高于无运动干预组，差异有统计学意义（P=0.012）；对于处理速度，干预后八段锦组数字符号测试评分明显高于快步走组和无运动干预对照组，差别有统计学意义（P<0.05）；对于记忆力，干预后八段锦可明显提高WMS总分、记忆商以及AVLT测试的大部分参数包括第一遍回忆个数、第二遍回忆个数、回忆个数总和、延时回忆个数等，相比于其他2组均具有显著统计学意义；对于执行功能，相比于其他2组，在TMT-A、TMT-B测试结果上无显著统计学差异。③在大脑血流动力学方面，八段锦可改善大脑前动脉血流速度，而且MoCA分数改变与其血流动力学参数改变呈正相关。④功能核磁数据分析显示八段锦运动可显著增强了MCI患者DMN双侧豆状壳核、左侧海马、左侧额下回、右侧额上回以及左侧颞中回等脑区的功能活动。⑤结构核磁数据显示八段锦运动可改善MCI患者左颞中回、左颞上回、右额上回、右额中回、右颞中回、右顶下小叶等脑区结构。由引可得，本研究证实八段锦运动可明显改善MCI患者的整体认知功能和记忆力及处理速度，且效果优于快步走，其机制与改善MCI患者DMN双侧豆状壳核、左侧海马、左侧额下回等脑区的功能活动，以及左颞中回、左颞上回、右额上回等脑区结构有关。为老年人群认知功能下降的预防或康复提供科学证据。