Saur Dorothee, Lange Rüdiger, Baumgaertner Annette, Schraknepper Valeska, Willmes Klaus, Rijntjes Michel, Weiller Cornelius
Department of Neurology, University Freiburg, Breisacher Strasse 64, 79106 Freiburg, Germany.
Brain. 2006 Jun;129(Pt 6):1371-84. doi: 10.1093/brain/awl090. Epub 2006 Apr 25.
Previous functional imaging studies of chronic stroke patients with aphasia suggest that recovery of language occurs in a pre-existing, bilateral network with an upregulation of undamaged areas and a recruitment of perilesional tissue and homologue right language areas. The present study aimed at identifying the dynamics of reorganization in the language system by repeated functional MRI (fMRI) examinations with parallel language testing from the acute to the chronic stage. We examined 14 patients with aphasia due to an infarction of the left middle cerebral artery territory and an age-matched control group with an auditory comprehension task in an event-related design. Control subjects were scanned once, whereas patients were scanned repeatedly at three consecutive dates. All patients recovered clinically as shown by a set of aphasia tests. In the acute phase [mean: 1.8 days post-stroke (dps)], patients' group analysis showed little early activation of non-infarcted left-hemispheric language structures, while in the subacute phase (mean: 12.1 dps) a large increase of activation in the bilateral language network with peak activation in the right Broca-homologue (BHo) was observed. A direct comparison of both examinations revealed the strongest increase of activation in the right BHo and supplementary motor area (SMA). These upregulated areas also showed the strongest correlation between improved language function and increased activation (r(BHo) = 0.88, r(SMA) = 0.92). In the chronic phase (mean: 321 dps), a normalization of activation with a re-shift of peak activation to left-hemispheric language areas was observed, associated with further language improvement. The data suggest that brain reorganization during language recovery proceeds in three phases: a strongly reduced activation of remaining left language areas in the acute phase is followed by an upregulation with recruitment of homologue language zones, which correlates with language improvement. Thereafter, a normalization of activation is observed, possibly reflecting consolidation in the language system.
以往针对慢性失语症中风患者的功能成像研究表明，语言恢复发生在一个预先存在的双侧网络中，未受损区域上调，病灶周围组织和右侧同源语言区域被募集。本研究旨在通过从急性期到慢性期的重复功能磁共振成像（fMRI）检查和平行语言测试，确定语言系统重组的动态变化。我们对14名因左大脑中动脉区域梗死导致失语的患者以及一个年龄匹配的对照组进行了事件相关设计的听觉理解任务检查。对照组只扫描一次，而患者在连续三个日期重复扫描。如一系列失语症测试所示，所有患者临床症状均有恢复。在急性期[平均：中风后1.8天（dps）]，患者组分析显示未梗死的左半球语言结构早期激活较少，而在亚急性期（平均：12.1 dps），观察到双侧语言网络激活大幅增加，右侧布洛卡同源区（BHo）激活达到峰值。两次检查的直接比较显示，右侧BHo和辅助运动区（SMA）的激活增加最为显著。这些上调区域在语言功能改善与激活增加之间也显示出最强的相关性（r（BHo） = 0.88，r（SMA） = 0.92）。在慢性期（平均：321 dps），观察到激活正常化，峰值激活重新转移到左半球语言区域，同时语言进一步改善。数据表明，语言恢复过程中的大脑重组分为三个阶段：急性期剩余左语言区域的激活大幅减少，随后是同源语言区域被募集的上调，这与语言改善相关。此后，观察到激活正常化，这可能反映了语言系统的巩固。
