Zahn Roland, Huber Walter, Drews Eva, Specht Karsten, Kemeny Stefan, Reith Wolfgang, Willmes Klaus, Schwarz Michael
Department of Neurology, Neurolinguistics Section, University of Technology, RWTH Aachen, Germany.
Neurocase. 2002;8(5):376-86. doi: 10.1076/neur.8.4.376.16189.
In a previous functional magnetic resonance imaging (fMRI) study with normal subjects, we demonstrated regions related to conceptual-semantic word processing around the first frontal sulcus (BA 9) and the posterior parietal lobe (BA 7/40) in agreement with several previous reports. We had the possibility, using the same fMRI paradigm, to study two consecutive cases with left middle cerebral artery (MCA) infarction (RC and HP) and lesions affecting either solely the pre-frontal (HP) or both the pre-frontal and posterior parietal part of the network activated in normal subjects (RC). Both patients showed transcortical sensory aphasia (TSA) on acute assessment. This contradicts classical disconnection accounts of the syndrome stating intact conceptual representations in TSA. Their recovery of language comprehension was associated with activation of a left hemispheric network. Mainly activations of left perilesional pre-frontal regions (RC), left Wernicke's area (RC and HP) or the left posterior middle and inferior temporal cortex (HP) were demonstrated in the TSA patients. The latter findings suggest that in our cases of TSA functional take-over has occurred in regions with related functions ('redundancy recovery') rather than in previously unrelated areas ('vicarious functioning'). Our data support distributed models of conceptual-semantic word processing and multiple left hemispheric representations of closely related functions.
在之前一项针对正常受试者的功能磁共振成像（fMRI）研究中，我们证实了与概念语义字词处理相关的区域位于额上沟（BA 9）和顶叶后部（BA 7/40）周围，这与之前的几份报告一致。我们有可能使用相同的fMRI范式，研究两例连续的大脑中动脉（MCA）左侧梗死患者（RC和HP），其病变分别仅影响前额叶（HP）或正常受试者中激活的网络的前额叶和顶叶后部（RC）。两名患者在急性评估时均表现为经皮质感觉性失语（TSA）。这与该综合征的经典分离学说相矛盾，该学说认为TSA患者的概念表征是完整的。他们语言理解能力的恢复与左侧半球网络的激活有关。在TSA患者中，主要表现为左侧病变周围前额叶区域（RC）、左侧韦尼克区（RC和HP）或左侧颞叶中后部及颞下皮质（HP）的激活。后一项发现表明，在我们的TSA病例中，功能接管发生在具有相关功能的区域（“冗余恢复”），而不是先前无关的区域（“替代功能”）。我们的数据支持概念语义字词处理的分布式模型以及密切相关功能的多个左侧半球表征。
