中文摘要：

目的 采用功能磁共振技术,探讨阿尔茨海默病（Alzheimer disease,AD）患者静息状态下的脑功能偏侧性的改变。方法 实验数据均来自ADNI（Alzheimer disease Neuroimaging Initiative）数据库,以17例右利手阿尔茨海默病患者为研究对象,19例右利手正常老年人作为对照。将全脑灰质随机划分为左右半球对称的256对种子区,基于功能连接分析法计算偏侧性指数（laterality index,LI）,量化分析静息态下脑功能偏侧性程度;计算0〈｜LI｜〈0.2、0.2≤｜LI｜〈0.4、0.4≤｜LI｜〈0.8、｜LI｜≥0.8四段阈值下的左偏LI之和及右偏LI之和,探索AD患者较正常老年人静息状态下的脑功能偏侧性是否存在改变。结果 对照组在0〈｜LI｜〈0.2、0.2≤｜LI｜〈0.4、0.4≤｜LI｜〈0.8阈值内左右半球偏侧性未见明显不同,在｜LI｜≥0.8的阈值内表现出明显的差异,体现出显著的左侧优势（P=0.005）;与对照组比较,AD患者在｜LI｜≥0.8阈值内左侧优势消失（P=0.06）,在0.4≤｜LI｜〈0.8阈值内出现显著的右侧优势（P=0.03）。结论 对照组静息态脑功能存在一定的偏侧性,该偏侧性主要体现在偏侧性较强范围内（｜LI｜≥0.8）,表现为左侧优势;AD组在偏侧性较强的范围内（0.8≤｜LI｜）左侧优势消失,可能是其特征性改变;AD组在偏侧性较弱的范围内（0.4≤｜LI｜〈0.8）表现出右侧优势,可能是与认知有关的脑功能代偿所致。

英文摘要：

Objective To investigate the lateralization of resting-state brain function in Alzheimer＇s disease（AD） using functional magnetic resonance （fMRI） technology. Methods Experimental data were downloaded from ADNI （Alzheimer disease Neuroimaging Initiative） database, with 17 right- handed Alzheimer＇s disease（AD） patients as the research objects and 19 right-handed normal elderly people as controls. Whole cerebral gray matter was randomly divided into 256 pairs of seed regions and the patterns of division in left and right hemispheres were symmetrical. The Laterality Index （LI） was calculated base on the functional connectivity analysis method for quantitative analysis of lateralization of brain function under the resting state. The sum of left lateralized LI and right lateralized LI under 0 〈 ｜LI｜ 〈 0. 2,0. 2 ≤｜LI｜ 〈 0.4,0.4 ≤ ｜LI｜〈 0. 8, ｜LI｜ ≥0.8 four thresholds were calculated to explore whether there was any change in the lateralization of resting-state brain function in AD patients. Results In the threshold of 0 〈 ｜LI｜〈0.2,0.2≤｜LI｜ 〈0.4,0.4≤ ｜LI｜ 〈0.8, there were no significant difference of lateralization between two hemispheres in the control group. In the threshold of ILI I ≥0.8, the control group showed significant interhemispheric differences （ P = 0. 005 ）, reflecting left hemisphere dominance. Compared with control group, the difference in left dominance at threshold ｜LI｜ ≥0.8 disappeared in AD patients （ P = 0. 06 ） and in the threshold of 0. 4 ≤｜LI｜ 〈 0. 8, AD patients showed distinct right hemisphere dominance （P = 0. 03 ）. Conclusion A left-lateralized dominance of resting-state brain function has been showed in the healthy subjects, mainly embodied in the relative more lateralized areas （ ｜LI｜≥ 0.8 ） ; the significant lateralization that showed in control group disappeared in AD patients, which maybe a characteristic change in AD patients; within the scope of relatively less lateralize