INSERM, Imagerie Cérébrale et Handicaps Neurologiques UMR 825, CHU Purpan, Toulouse, France.
Eur J Phys Rehabil Med. 2009 Dec;45(4):547-58. Epub 2009 Sep 22.
It has long been a matter of debate whether recovery from aphasia after left perisylvian lesion is mediated by perilesional left hemispheric regions or by right homologous areas. To investigate the neural substrates of aphasia recovery, a longitudinal study in patients after a left single perisylvian stroke was performed.
Thirteen aphasic patients were H2(15)O PET-scanned twice at a one year interval during a word generation task. Patients are divided into two groups according to language performance for the word generation task at PET2. For the Good Recovery (GR) group, patients' performances are indistinguishable from those of normal subjects, while patients from the Poor Recovery (PR) group keep language disorders. Using SPM2, Language-Rest contrast is computed for both groups at both PET stages. Then, Session Effect contrast (TEP2-TEP1>0) is calculated for both groups.
For the GR group, the Session Effect contrast shows an increase of activations in the left Postero-Superior Temporal Gyrus PSTG but also in the right thalamus and lenticular nuclei; for PR patients, the right lenticular nucleus activation is more important at PET1 than PET2.
The crucial role of the left temporal activation is confirmed and its increase is linked to behavioural recovery. The role of the right basal ganglia to support good recovery from aphasia is a new finding. Their activation may be more task-dependant and related to inhibition of the right frontal cortex.
左大脑外侧裂周围损伤后失语症的恢复是通过损伤侧左半球区域还是通过右侧同源区域介导的，这一直是一个争论的问题。为了研究失语症恢复的神经基础，对左单一外侧裂卒中后的患者进行了一项纵向研究。
13 名失语症患者在一年的间隔时间内进行了两次 H2(15)O PET 扫描，在单词生成任务期间。根据患者在 PET2 时的单词生成任务的语言表现，将患者分为两组。对于良好恢复（GR）组，患者的表现与正常受试者无异，而语言障碍持续存在于较差恢复（PR）组患者中。使用 SPM2，在两个 PET 阶段对两组进行语言 - 休息对照（Language-Rest contrast）。然后，对两组进行会话效应对照（Session Effect contrast，TEP2-TEP1>0）。
对于 GR 组，会话效应对照显示左后上颞叶 PSTG 的激活增加，但右侧丘脑和豆状核也有激活；对于 PR 患者，在 PET1 时右侧豆状核的激活比 PET2 时更重要。
左颞叶激活的关键作用得到了证实，其增加与行为恢复有关。右侧基底节在支持失语症良好恢复中的作用是一个新发现。它们的激活可能更依赖于任务，与右侧额叶皮层的抑制有关。
