Bethmann Anja, Tempelmann Claus, De Bleser Ria, Scheich Henning, Brechmann André
Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany.
Brain Res. 2007 Feb 16;1133(1):145-57. doi: 10.1016/j.brainres.2006.11.057. Epub 2006 Dec 19.
For imaging studies on hemispheric specialization of the human brain, data about known functional asymmetries other than handedness would be valuable for a reliable interpretation of lateralized activation in individuals or groups of subjects. As certain aspects of language processing are observed to be a function of primarily the left, it can be used as a reference for other asymmetric processes such as sensory or cognitive skills. For analyzing language laterality, there are a variety of methods, but these differ in application or accuracy. In this study, we tested the reliability of two widely used methods - dichotic listening and fMRI - to determine language dominance in 30 individual subjects. The German adaptation of a dichotic listening test (Hättig, H., Beier, M., 2000. FRWT: a dichotic listening test for clinical and scientific contexts, Zeitschr f Neuropsychologie 11. 233-245.) classified 54% of the 26 right-handed subjects as left hemispheric dominant. The results of the fMRI paradigm (Fernández, G., de Greiff, A., von Oertzen, J., et al., 2001. Language mapping in less than 15 min: real-time functional MRI during routine clinical investigation. Neuroimage 14, 585-594.) tested on the same subjects, however, classified 92% of the right-handed subjects as left dominant. The main reason for this discrepancy was that the ear dominance score of many subjects in the dichotic listening test was too low to determine a reliable ear advantage. As a consequence, this specific dichotic listening test cannot be used to determine language laterality in individual subjects. On the other hand, the fMRI results are consistent with numerous studies showing left dominant language processing in more than 90% of right-handers. In some subjects, however, language laterality critically depends on the areas used to determine the laterality index.
对于人类大脑半球特化的成像研究，除利手之外的已知功能不对称数据，对于可靠解释个体或受试者群体的偏侧化激活情况很有价值。由于观察到语言处理的某些方面主要是左脑的功能，它可作为其他不对称过程（如感觉或认知技能）的参考。分析语言偏侧化有多种方法，但这些方法在应用或准确性上存在差异。在本研究中，我们测试了两种广泛使用的方法——双耳分听和功能磁共振成像（fMRI）——以确定30名个体受试者的语言优势半球。双耳分听测试的德语改编版（Hättig, H., Beier, M., 2000. FRWT: a dichotic listening test for clinical and scientific contexts, Zeitschr f Neuropsychologie 11. 233 - 245.）将26名右利手受试者中的54%归类为左半球优势。然而，在同一受试者身上进行的功能磁共振成像范式测试（Fernández, G., de Greiff, A., von Oertzen, J., et al., 2001. Language mapping in less than 15 min: real-time functional MRI during routine clinical investigation. Neuroimage 14, 585 - 594.）将92%的右利手受试者归类为左半球优势。这种差异的主要原因是，在双耳分听测试中，许多受试者的耳优势得分过低，无法确定可靠的耳优势。因此，这种特定的双耳分听测试不能用于确定个体受试者的语言偏侧化。另一方面，功能磁共振成像结果与众多研究一致，这些研究表明超过90%的右利手者语言处理以左半球为主。然而，在一些受试者中，语言偏侧化严重依赖于用于确定偏侧化指数的区域。
