Stern Y, Moeller J R, Anderson K E, Luber B, Zubin N R, DiMauro A A, Park A, Campbell C E, Marder K, Bell K, Van Heertum R, Sackeim H A
Department of Neurology, College of Physicians and Surgeons of Columbia University, New York, NY, USA.
Neurology. 2000 Nov 14;55(9):1291-7. doi: 10.1212/wnl.55.9.1291.
To determine whether the pathologic mechanisms of AD alter the brain networks subserving performance of a verbal recognition task.
Functional imaging studies comparing task-related activation in AD patients and controls generally have not used network analysis and have not controlled for task difficulty.
H2 15O PET was used to measure regional cerebral blood flow in 14 patients and 11 healthy elders during the performance of a serial verbal recognition task under two conditions: low demand, with study list size (SLS) equal to one; and titrated demand, with SLS adjusted so that each subject recognized words at 75% accuracy. The Scaled Subprofile Model was used to identify networks of regionally covarying activity across these task conditions.
In the elders, higher SLS was associated with the recruitment of a network of brain areas involving left anterior cingulate and anterior insula (R2 = 0.94; p < 0.0001). Three patients also expressed this network. In the remaining patients, higher SLS was associated with the recruitment of an alternate network consisting of left posterior temporal cortex, calcarine cortex, posterior cingulate, and the vermis (R2 = 0.81, p < 0.001). Expression of this network was unrelated to SLS in the elders and more intact AD patients.
The patients' use of the alternate network may indicate compensation for processing deficits. The transition from the normal to the alternate network may indicate a point where brain disease has irreversibly altered brain function and thus may have important implications for therapeutic intervention.
确定阿尔茨海默病（AD）的病理机制是否会改变支持言语识别任务表现的脑网络。
比较AD患者和对照组任务相关激活的功能成像研究通常未使用网络分析，也未控制任务难度。
在两种条件下，使用H2 15O PET测量14例患者和11名健康老年人在执行系列言语识别任务时的局部脑血流量：低需求，学习列表大小（SLS）等于1；滴定需求，调整SLS使每个受试者以75%的准确率识别单词。使用缩放子剖面模型识别这些任务条件下区域协变活动的网络。
在老年人中，较高的SLS与涉及左前扣带回和前岛叶的脑区网络的激活相关（R2 = 0.94；p < 0.0001）。三名患者也表现出这个网络。在其余患者中，较高的SLS与由左后颞叶皮质、距状皮质、后扣带回和蚓部组成的替代网络的激活相关（R2 = 0.81，p < 0.001）。这个网络的表现与老年人和病情较轻的AD患者的SLS无关。
患者对替代网络的使用可能表明对加工缺陷的补偿。从正常网络到替代网络的转变可能表明脑部疾病已不可逆转地改变了脑功能，因此可能对治疗干预具有重要意义。
