A longitudinal study involving stimulation brain mapping of a German-French bilingual patient with grade II glioma

Köpke, B. 1, 3 , Prodhomme, K. 1, 3 & Lubrano, V. 2, 3

1 Octogone-Lordat, University of Toulouse (UTM)
2 Inserm U825, CHU Toulouse
3 Institut des Sciences du Cerveau, IFR n°96

Low grade tumours are pre-cancerous tumours, evolving slowly and infiltrating the cerebral parenchyme. Due to these characteristics, cerebral plasticity allows that patients generally present no or only small cognitive impairments at time of diagnosis. The treatment involves the suppression of a maximum of the tumour, without altering the patient’s quality of life. When the glioma is located near or within eloquent sensori-motor or language brain regions, awake surgery with direct electric stimulations applied to language is used in order to preserve the language skills of the patient. But this technique provides also valuable stimulation data which complement functional brain imaging data. This is of particular interest for the brain mapping of language functions in bilinguals where fRMI data, for example, do not necessarily allow the disentangling of the activation of one language and the inhibition of the other.
The paper reports on the clinical study of a 31-year old bilingual female presenting a left premotor WHO grade II glioma. The patient is a late bilingual with L1 German who learned English and French from 10 years on and moved to France at age 20 where she mostly uses French now. Oral language skills - both left and right hemisphere language functions - were assessed preoperatively with the German and French BAT and a German adaptation and the French MEC. During awake craniotomy in November 2008, both languages were mapped with naming and writing tasks. Since surgery, the patient is followed longitudinally every 6 month and language skills are assessed with BAT and MEC. We will present behavioral and brain mapping data and discuss their relevance with respect to the neural representation of languages in healthy bilingual speakers, with specific attention to the role of age of acquisition.