Words and objects at the tip of the left temporal lobe in primary progressive aphasia
Words and objects at the tip of the left temporal lobe in primary progressive aphasia
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DOI：
10.1093/brain/aws336
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发表时间：
2013-02-01
期刊：
影响因子：
14.5
通讯作者：
Rogalski, Emily J.
中科院分区：
文献类型：
--
作者：
Mesulam, M. -Marsel;Wieneke, Christina;Rogalski, Emily J.
69例前瞻性入组的原发性进行性失语症患者中有11例被选入本研究，因为萎缩高峰部位主要或完全位于左颞叶前部。这些区域的皮质体积减少到不到对照值的一半，而左半球其他地方的平均体积仅偏离对照值8%。未能命名物体是最一贯和最严重的缺陷。如果对象不能被命名，即使当指示词被理解，对象识别和两者准确匹配，则错误归因于纯粹的检索失败。令人惊讶的是，许多命名错误反映了纯粹的检索失败，没有可辨别的语义或联想成分。剩下的一组错误具有关联组件。这些错误反映了无法定义的词表示的对象往往比无法定义的性质所描绘的对象。在一个单独的任务中，同一个物体必须与语言或非语言联想联系在一起，只有在语言形式中表现异常。过度的分类干扰，观察图片-文字，但不是图片-图片，匹配任务。这种过度的干扰反映了范畴内而不是范畴间的区别模糊不清，就好像词-客体关联的敏锐度被削弱了，因此在类属层面上的对应比在具体层面上的对应更容易识别。对象知识的语言和非语言标记之间的这些分离表明，在左颞尖的峰值萎缩部位的神经质量减少，占假定的发病前体积的一半或更多，不太可能包含在严格的非模态中枢中预期的类型的域独立的语义表征。一个更可能的安排需要两个高度互动的路线，一个强烈的左偏颞侧语言网络的口头概念，和一个大概更双边或右侧的下颞/梭状的物体识别网络，这仍然相对幸免，因为高峰萎缩网站集中在左边。目前的研究结果还表明，左前颞叶新皮层应插入到语言网络中，它可能在选择物体的语言标签和调解单词理解从通用到特定精度水平的进展中发挥重要作用。
Eleven of 69 prospectively enrolled primary progressive aphasics were selected for this study because of peak atrophy sites located predominantly or exclusively within the anterior left temporal lobe. Cortical volumes in these areas were reduced to less than half of control values, whereas average volume elsewhere in the left hemisphere deviated from control values by only 8%. Failure to name objects emerged as the most consistent and severe deficit. Naming errors were attributed to pure retrieval failure if the object could not be named even when the denoting word was understood, the object recognized and the two accurately matched. Surprisingly many of the naming errors reflected pure retrieval failures, without discernible semantic or associative component. The remaining set of errors had associative components. These errors reflected the inability to define the word denoting the object more often than the inability to define the nature of the pictured object. In a separate task where the same object had to be linked to verbal or non-verbal associations, performance was abnormal only in the verbal format. Excessive taxonomic interference was observed for picture-word, but not picture-picture, matching tasks. This excessive interference reflected a blurring of intra-rather than inter-category distinctions as if the acuity of word-object associations had been diminished so that correspondences were easier to recognize at generic than specific levels. These dissociations between verbal and non-verbal markers of object knowledge indicate that the reduced neural mass at peak atrophy sites of the left temporal tip, accounting for half or more of the presumed premorbid volume, was unlikely to have contained domain-independent semantic representations of the type that would be expected in a strictly amodal hub. A more likely arrangement entails two highly interactive routes-a strongly left lateralized temporosylvian language network for verbal concepts, and a presumably more bilateral or right-sided inferotemporal/fusiform object recognition network, which remained relatively spared because peak atrophy sites were concentrated on the left. The current results also suggest that the left anterior temporal neocortex should be inserted into the language network where it is likely to play a major role in selecting verbal labels for objects and mediating the progression of word comprehension from generic to specific levels of precision.