应用静息态功能磁共振对左侧颞叶癫痫患者言语工作记忆的研究

Resting State fMRI Study of the Cerebral Network of Verbal Working Memory in Patients with Left Temporal Lobe Epilepsy

目的应用静息态功能磁共振成像研究左侧颞叶癫痫(lTLE)患者言语工作记忆(VWM)功能连接及与认知功能的关系。方法应用数字广度测试研究受试者工作记忆认知功能;采用任务态功能磁共振寻找16名健康志愿者的VWM的感兴趣区(ROI);运用静息态功能磁共振成像对11例lTLE患者和16名健康志愿者进行扫描,使用功能连接方法处理两组数据,并对功能连接结果与认知功能行相关分析。结果 lTLE组的数字广度测试顺背和倒背成绩均显著降低;健康志愿者VWM激活脑区主要在左右侧前额叶、顶叶和小脑后叶,左侧大脑半球激活的体素范围及强度均比右侧显著;静息态下,lTLE组的左侧前额叶与左右侧顶叶、右侧顶叶和右侧小脑之间的功能连接强度下降明显,但功能连接强度与数字广度测试成绩无相关性。结论 VWM具有左侧偏侧性;lTLE患者VWM主要脑区功能连接强度降低,表明连接网络异常;但未发现功能连接强度降低与行为测试结果相关。

Objective To investigate the functional connectivity of the brain network of verbal working memory （VWM） in patients with left temporal lobe epilepsy （LTLE） by using resting state functional magnetic resonance imaging （rs fMRI） , and to analyze its relationship with the cognitive function. Methods Digit span test was adopted to assess the verbal working memory for all the subjects. Task-based functional magnetic resonance imaging （task-based fMRI） was used to search for the regions of interest （ROI） in 16 healthy volunteers. The rs-fMRI scanning was performed in ll LTLE patients as well as in 16 healthy volunteers. The data thus obtained were analyzed and compared between the two groups. Using correlation analysis method the relationship between functional connectivity strength and the performance was assessed. Results Both the forward test score and the backward test score obtained from the digit span test were significantly dropped in LTLE patients; the task-based fMRI scanning showed that the main VWM activation areas in healthy volunteers were at the left and right prefrontal cortex, parietal cortex and the posterior lobe of the cerebellum. The VWM-correlated brain activated voxels of the left hemisphere were more significant in the spatial distribution and intensity than those of the right hemisphere. At rest status, in LTLE patients the functional connectivity strength between left prefrontal cortex and left parietal cortex, between left prefrontal cortex and right parietal cortex, as well as between right parietal cortex and right cerebellar posterior lobe was strikingly decreased, although no positive correlation existed between the functional connectivity strength and the performance of the digit span test. Conclusion VWM has left hemilateral inclination. In LTLE patients the functional connectivity strength of main cerebral functional regions is decreased, indicating that the brain network of verbal working memory is abnormal. Nevertheless, there is no positive correlation between the functional connectivity strength and the performance of the digit span test.