遗忘型轻度认知障碍患者默认网络动态功能连接研究

Dynamic functional connectivity of default network in amnestic mild cognitive impairment patients

目的研究遗忘型轻度认知障碍(amnestic mild cognitive impairment,aMCI)患者默认网络动态功能连接变化及其与认知功能的相关性。方法收集24例aMCI患者及55例正常对照组静息态功能磁共振影像及认知功能数据。利用滑动时间窗(sliding time window,SW)方法分析动态功能连接变化,比较两组间默认网络动态功能连接时间特征参数(时间占比、状态转换次数、平均居留时间、自身转移概率)差异,计算与简易精神状态量表(mini-mental state examination,MMSE)评分的相关性。结果默认网络显示强连接和弱连接两种动态功能连接模式。与正常组比较,aMCI患者强连接状态平均居留时间明显增加(P=0.005),自身转移概率增高(P=0.008)。aMCI患者强弱状态间转换次数与MMSE评分呈正相关(P=0.034,r=0.433)。结论aMCI患者较正常人默认网络动态功能连接时间特征发生改变,且与认知功能下降相关,这一发现为早期诊断aMCI提供了新思路。

Objective To investigate the changes of default mode network(DMN)dynamic functional connectivity(dFC)and its correlation with cognitive function in patients with amnestic mild cognitive impairment(aMCI).Methods Resting-state functional MRI data and cognitive function scores of 24 patients with aMCI and 55 normal subjects(control group)were collected.The difference of DMN static functional connection between the two groups was compared.A sliding time window(SW)approach was adopted to extract the characteristics of dFC in DMN,and the fraction time,numbers of transitions,mean dwell time,probability of transitions were compared between the two groups.The relationship between the characteristics of dFC in DMN and mini-mental state examination(MMSE)scores was analyzed.Results DMN showed strongly connected state and weakly connected state.Compared with normal controls,aMCI patients exhibited increased mean dwell time(P=0.005)and higher probability of transitions(P=0.008)of strongly connected state.The numbers of transitions in aMCI patients were positively correlated with MMSE score(P=0.034,r=0.433).Conclusion There are changes of temporal characteristics of dFC in DMN among aMCI patients,which are related to the decline of cognitive function.These findings may provide new clues for the early diagnosis of aMCI.