Helmstaedter C, Fritz N E, González Pérez P A, Elger C E, Weber B
Department of Epileptology, University of Bonn, Sigmund-Freud Str. 25, 53127 Bonn, Germany.
Epilepsy Res. 2006 Aug;70(2-3):257-62. doi: 10.1016/j.eplepsyres.2006.03.005. Epub 2006 Apr 19.
Atypical, i.e. right hemisphere language dominance is frequently observed in early onset left hemisphere epilepsies. In left mesial temporal lobe epilepsy, where eloquent cortex is not directly involved, it is a matter of debate, to which degree atypical language dominance is driven not only by morphological lesions but also by epileptic dysfunction, and whether atypical dominance is hardwired or not. Taking this as the background this study evaluated the hypothesis that epilepsy driven atypical dominancy might be reversible when seizures are successfully controlled. This was evaluated in patients with left mesial temporal lobe epilepsy, who were atypically language dominant by means of language fMRI before surgery, and became seizure free after left selective amygdalo-hippocampectomy. Three out of 53 consecutive atypically dominant patients with chronic epilepsy fulfilled these criteria. Postoperative follow-up language fMRI indicated reversal of right into left dominance in one patient going along with unexpected losses in verbal memory performance. The two other patients experienced unchanged or even enhancement of the pre-existing dominance pattern, going along with consistent postoperative performance changes in cognition. The data thus provide supporting evidence that atypical language dominance can indeed be functionally driven and moreover that in at least some patients, right hemispheric language can shift-back to the left hemisphere when the driving factor, i.e. seizures, becomes successfully controlled. The results have clinical implications for outcome prediction after brain surgery in atypically dominant patients with epilepsy. However, further research in larger groups of atypically dominant patients is required to identify the conditions under which atypical dominance becomes hardwired and when not.
非典型情况，即右半球语言优势在早发性左半球癫痫中经常被观察到。在左侧颞叶内侧癫痫中，明确的皮质未直接受累，非典型语言优势在多大程度上不仅由形态学病变驱动，还由癫痫功能障碍驱动，以及非典型优势是否是固定的，这是一个有争议的问题。以此为背景，本研究评估了这样一个假设，即当癫痫发作得到成功控制时，癫痫驱动的非典型优势可能是可逆的。在术前通过语言功能磁共振成像显示为非典型语言优势、且在左侧选择性杏仁核-海马切除术后无癫痫发作的左侧颞叶内侧癫痫患者中对此进行了评估。连续的53例非典型优势慢性癫痫患者中有3例符合这些标准。术后随访语言功能磁共振成像显示，1例患者的优势从右侧逆转至左侧，同时言语记忆表现出现意外下降。另外2例患者的优势模式保持不变甚至增强，同时术后认知表现持续改变。这些数据因此提供了支持性证据，表明非典型语言优势确实可以由功能驱动，而且至少在一些患者中，当驱动因素即癫痫发作得到成功控制时，右半球语言可以转回左半球。这些结果对非典型优势癫痫患者脑手术后的预后预测具有临床意义。然而，需要对更大组的非典型优势患者进行进一步研究，以确定非典型优势在何种情况下是固定的，何种情况下不是。
