Gerschlager W, Lalouschek W, Lehrner J, Baumgartner C, Lindinger G, Lang W
Department of Clinical Neurology, University of Vienna, Austria.
Electroencephalogr Clin Neurophysiol. 1998 Apr;108(3):274-82. doi: 10.1016/s0168-5597(97)00099-3.
There are current attempts to replace the WADA test for pre-surgical evaluation of hemispheric language capabilities by one of the methods of functional brain imaging. Recent PET and fMRI studies using verbal cognitive tasks like verb generation, semantic monitoring or semantic ('deep') encoding of words showed asymmetries of activation in the fronto-lateral cortex. In a previous ERP study subjects were required to indicate whether pronounceable non-words and abstract geometric figures were presented for the first time ('new item') or whether they had been shown before ('old item'). Group analyses of this study showed significant material-specific hemispheric asymmetries with ERPs being more negative-going in recordings of the posterior part of the left hemisphere with verbal material (CP5/6) but more negative-going in recordings of the right hemisphere with the spatial material (P7/8). The aim of the present study was to test statistically ERP lateralization effects in individual healthy subjects as well as WADA-tested patients suffering from seizures of the mesio-temporal lobe (MTL). In all subjects ERP lateralization with verbal material was tested in the electrode pair CP5/6, and ERP lateralization with figures in the electrode pair P7/8. Statistical analyses of single trials showed that in 20 out of 24 subjects ERPs with verbal material started to be more negative-going in CP5 as compared to CP6 in the period between 100 and 200 ms after stimulus onset or the subsequent time epoch (200-300 ms). In one subject not CP5/6 but the closely adjacent electrode pair P7/P8 showed this verbal material-related hemispheric effect. In patients language dominance as indicated by ERPs was not always consistent with the data of the WADA test. In one patient with left MTL seizures ERPs with verbal material and figures were found to be significantly lateralized to the right hemisphere although the WADA test assigned this patient to have a language-dominant left hemisphere.
目前有人尝试用功能性脑成像方法之一来取代用于术前评估半球语言能力的WADA测试。最近使用诸如动词生成、语义监测或单词语义（“深度”）编码等言语认知任务的PET和fMRI研究显示，额外侧皮质存在激活不对称。在之前的一项ERP研究中，要求受试者指出可发音的非单词和抽象几何图形是首次呈现（“新项目”）还是之前已经展示过（“旧项目”）。该研究的组分析显示，存在显著的材料特异性半球不对称，对于言语材料（CP5/6），ERP在左半球后部记录中更偏向负向，但对于空间材料（P7/8），ERP在右半球记录中更偏向负向。本研究的目的是统计测试个体健康受试者以及经WADA测试的患有颞叶内侧（MTL）癫痫的患者的ERP偏侧化效应。在所有受试者中，使用电极对CP5/6测试言语材料的ERP偏侧化，使用电极对P7/8测试图形的ERP偏侧化。单次试验的统计分析表明，在24名受试者中的20名中，与CP6相比，言语材料的ERP在刺激开始后100至200毫秒或随后的时间段（200 - 300毫秒）内，在CP5处开始更偏向负向。在一名受试者中，不是CP5/6而是紧邻的电极对P7/P8显示出这种与言语材料相关的半球效应。在患者中，ERP所显示的语言优势并不总是与WADA测试的数据一致。在一名患有左侧MTL癫痫的患者中，发现言语材料和图形的ERP显著偏向右侧半球，尽管WADA测试将该患者判定为语言优势在左侧半球。
