认知障碍患者背外侧前额叶功能连接与认知-步行能力的关系研究

Relationship between DLPFC functional connectivity and dual task-walking ability in patients with cognitive impairment

目的:本研究采用功能磁共振研究主观认知下降(subjective cognitive decline,SCD)及轻度认知障碍(mild cognitive impairment,MCI)患者的背外侧前额叶(dorsal lateral prefrontal cortex,DLPFC)与运动控制相关脑区的功能连接的特征性改变,并探索其与认知评估及双重任务下步态参数之间的关系。方法:共纳入76例中老年人,根据分组标准分为MCI组(25例)、SCD组(29例)和正常对照(normal control,NC)组(22例)。对入组中老年人进行神经心理学测评、静息态功能磁共振扫描和双重任务步态采集。计算出左侧DLPFC和双侧额上回内侧部、楔前叶、颞中回的功能连接(functional connectivity,FC)值并采用多元线性回归分析其与认知-步行能力之间的关系。结果:三组间年龄、性别比、基础病等基本资料无显著性差异(P>0.05)。三组间多项神经心理学测试结果有显著性差异(P<0.05)。MCI组与SCD组及NC组相比,双侧DLPFC与多个脑区的功能连接增强,且功能连接增强受到执行功能和记忆功能下降、认知消耗增高和双重任务步速减慢的影响(P<0.05)。结论:相比于SCD患者和健康中老年人,MCI患者双侧DLPFC与额、颞、顶叶多个脑区之间的功能连接出现代偿性增强。静息状态下左侧DLPFC功能连接受到记忆、执行功能、双重任务消耗、双重任务步速及年龄影响。

Objective:To study the characteristic changes in functional connectivity between dorsolateral prefrontal cortex(DLPFC) and motor control related brain regions in middle aged and elderly people with subjective cognitive decline(SCD) and mild cognitive impairment(MCI) by functional imaging studies. We aimed to explore the relationship between gait parameters,cognitive assessment and dual tasking in SCD and MCI elderly.Method:Seventy-six middle aged and elderly people were recruited with MCI(n=25),SCD(n=29) and normal control(n=22). Neuropsychological assessment, resting state f MRI scanning and dual task gait analysis were performed. The values of functional connectivity(FC) between left DLPFC with medial superior frontal gyrus, precuneus lobe and middle temporal gyrus were obtained and the relationship between FC values and dual task-walking ability was analyzed.Result:There was no significant difference in age,sex ratio and basic characteristics among the three groups(P>0.05). There were significant differencew in neuropsychological test results among the three groups(P<0.05). Enhanced functional connectivity of bilateral DLPFC with multiple brain regions was observed in MCI group compared to SCD and NC group. This functional connectivity was reflected by the decline in executive and memory functions,increased cognitive consumption and slowing of dual task walking speed(P<0.05).Conclusion: Functional connectivity between bilateral DLPFC, frontal and temporal, parietal lobes showed compensatory enhancement in MCI compared to SCD and healthy middle aged and elderly people. Left DLPFC functional connectivity was reflected by memory, executive function, dual task consumption, dual task walking speed and age.