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Unformatted text preview: Acta Neurochir (Wien) (2007) 149: 1109–1116 DOI 10.1007/s00701-007-1266-2 Printed in The Netherlands Clinical Article Review of language organisation in bilingual patients: what can we learn from direct brain mapping? C. Giussani 1 ; 2 , F.-E. Roux 2 , V. Lubrano 2 , S. M. Gaini 1 , L. Bello 1 1 Department of Neurological Sciences, Neurosurgery, Universita’ degli Studi di Milano, Milano, Italy 2 Institut National de la Sant e Et de la Recherche M edicale, U825, F ed eration de Neurochirurgie, Centres Hospitaliers Universitaires, Toulouse, France Received 23 November 2006; Accepted 26 June 2007; Published online 23 August 2007 # Springer-Verlag 2007 Summary Although the majority of people worldwide are bilin- gual, the brain representation of language in bilingual persons is still a matter of debate. Since the beginning of the studies conducted on bilinguals, most authors denied that learning a new language requires a new semantic processing or the involvement of new cortical areas. In this paper, we review neurosurgical studies using direct electrocortical or subcortical stimulation techniques for brain mapping in bilingual subjects and compare this data with that obtained from other brain mapping meth- ods. The authors focused on the most controversial issue whether multiple languages are represented in common or distinct cerebral areas. Seven direct brain mapping studies from different teams focused on bilingualism and multilingualism. All these studies showed that even if cerebral representation of language in multilingual patients could be grossly located in the same cortical region, it was possible to individualise distinct language-specific areas by direct cortical stimulation in the dominant frontal and tem- poro-parietal regions. Task- and language-specific sites were also described, demonstrating an important special- isation of some cortical areas. Using subcortical stim- ulation, some authors were able to find specific white matter tracts for different languages. Finally, all authors recommend in bilingual patients who need brain map- ping for neurosurgical purpose to test all languages in which the subjects are fluent. Keywords: Bilingualism; multilingualism; awake sur- gery; brain mapping; electrostimulation technique. Abbreviations Introduction After the discovery by Broca of the existence of specific brain structures dedicated to language, many specula- tions have been developed about how multiple languages are represented in the brain. In 1867, a Scottish physi- cian, Scoreby-Jackson, was the first to hypothesise that distinct and specific language sites were present for each language in bilinguals . In this period, following the description of Broca’s area and coinciding with the stream of localisationist theories, the hypothesis that distinct brain regions could be specifically involved in different languages was born . This hypothesis was sustained by the observation that different aphasiogenic cerebral injuries could produce differential or selective...
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- Fall '10
- bilinguals, brain mapping