2型糖尿病患者工作记忆的功能磁共振成像研究

An investigation on the working memory in Type 2 diabetes mellitus using BOLD fMRI

目的应用任务态功能磁共振成像研究2型糖尿病(T2DM)患者工作记忆相关脑区和认知功能的关系,以助于理解T2DM患者工作记忆受损的发生机制。方法按照纳入标准选取30例T2DM患者作为实验组,招募30例年龄、性别及受教育程度相匹配的健康志愿者作为对照组。采用Siemens Trio Tim 3.0T超导磁共振扫描仪对所有被试者进行基于组块设计n-back任务态功能成像扫描,扫描前对所有被试进行神经心理认知测试。采用MATLAB 2010软件及SPM8软件对BOLD-fMRI成像数据进行预处理,筛选出符合要求的10例T2DM患者和12例健康对照者被试数据,采用SPM8软件进行组内、组间分析,分析两组间工作记忆相关脑区的改变。结果 1神经心理认知测试中,在2-back条件下T2DM组较NC组表现减弱,T2DM组反应时间为(745.15±180.80)s,NC组反应时间为(604.16±118.70)s,T2DM组反应时间延长,差异有统计学意义(P<0.05)。2在组块设计n-back实验下,相较于NC组,T2DM组在左额上回、右额下回、双侧辅助运动脑区、左侧前扣带回激活减弱。T2DM患者在左顶下小叶、右顶上小叶、右枕叶激活增多。结论1当T2DM患者未出现明显认知障碍,已经出现工作记忆的受损。2基于fMRI的组块设计n-back实验对激活工作记忆脑网络较敏感,T2DM患者存在工作记忆相关脑区的改变。

Objective To investigate the brain function in T2 DM patients during a working memory task using a blood oxygenation level-dependent functional resonance imaging（BOLD-fMRI）experiment and the potential of enhancing our understanding of the mechanisms of congnitive dysfunction in T2 DM patients. Methods 30 patients with T2 DM and 30 demographically matched right-handed euglycemic subjects were recruited. Mini-mental state examination（MMSE）, Trail Making Test（TMT）, Digit Span Test（DST）were performed. BOLD fMRI were performed with a 3.0 Siemens Trio Trim MR System to obtain brain activations during a working memory task： the digit n-back paradigm（0-back and 2-back）. Any scan in which the head motion was larger than 2 mm was excluded from further analysis. In the present study, twelve right-handed middle-aged T2 DM patients and ten controls were included in the analysis. Functional data preprocessing was performed using MATLAB 2010. Then the preprocessed MRI data were analyzed with group and individual analysis and with independent two-sample t test using SPM8. Results 1 During the n-back task, comparing with the control group, patients with T2 DM performed badly on the 2-back condition, need a significant longer reaction time and have a little lower accuracy than controls. 2 During the n-back task, patients with T2 DM showed less activation in bilateral prefrontal cortices（PFC）, bilateral premotor areas（PM）and the left anterior cingulater cortex（ACC）than the normal controls. T2 DM patients have increased activation with bilateral parietal cortices（PA）and bilateral occpiatal cortexs,compared compared to normal controls. Conclusions 1 Before T2 DM patients were associated with cognitive impairments, such as psychomotor speed or executive function, they were already found to have impairment of working memory probability. 2 The impairments and increased activation of working memory related brain in T2 DM patients indicated an impact by chronic hyperglycemia on patients＇ working memory network.