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Toulouse, France

Roux F.-E.,UMR Unite 825 | Dufor O.,UMR Unite 825 | Lauwers-Cances V.,Centres Hospitalo Universitaires | Boukhatem L.,Pole Neurosciences | And 4 more authors.
Neurosurgery | Year: 2011

BACKGROUND: Cortical and subcortical electrostimulation mapping during awake brain surgery for tumor removal is usually used to minimize deficits. OBJECTIVE: To use electrostimulation to study neuronal substrates involved in spatial awareness in humans. METHODS: Spatial neglect was studied using a line bisection task in combination with electrostimulation mapping of the right hemisphere in 50 cases. Stimulation sites were identified with Talairach coordinates. The behavioral effects induced by stimulation, especially eye movements and deviations from the median, were quantified and compared with preoperative data and a control group. RESULTS: Composite and highly individualized spatial neglect maps were generated. Both rightward and leftward deviations were induced, sometimes in the same patient but for different stimulation sites. Group analysis showed that specific and reproducible line deviations were induced by stimulation of discrete cortical areas located in the posterior part of the right superior and middle temporal gyri, inferior parietal lobe, and inferior postcentral and inferior frontal gyri (P < .05). Fiber tracking identified stimulated subcortical areas important to spare as sections of fronto-occipital and superior longitudinal II fascicles. According to preoperative and postoperative neglect battery tests, the specificity and sensitivity of intraoperative line bisection tests were 94% and 83%, respectively. CONCLUSION: In humans, discrete cortical areas that are variable in location between individuals but mainly located within the right posterior Sylvian fissure sustain visuospatial attention specifically toward the contralateral or ipsilateral space direction. Line bisection mapping was found to be a reliable method for minimizing spatial neglect caused by brain tumor surgery. Copyright © 2011 by the Congress of Neurological Surgeons.

Borius P.-Y.,Centres Hospitalo Universitaires | Giussani C.,UMR Unite 825 | Draper L.,Centres Hospitalo Universitaires | Roux F.-E.,Centres Hospitalo Universitaires | Roux F.-E.,UMR Unite 825
Cortex | Year: 2012

Direct cortical electrostimulation was used to study cortical areas hypothetically involved in translation in bilinguals during brain tumour resections, with a view to sparing these functional areas. A series of seven proficient bilingual patients was studied: two left-handed and five right-handed individuals with no pre-existing language deficit. Hemispheric cortex (on the side contralateral to the patient's hand-dominance) was directly stimulated whilst the patient performed naming and reading tasks in both languages and a translation task (of a written text from their second 'learned' language to their first or 'native' language). Of the 147 different cortical sites studied, 26 'language functional sites' were detected, where electrostimulation affected reading and/or naming in the patient's native and/or second learned language. Of these, 8 sites (in 4 patients) were "task-specific" and "language-specific" i.e., affecting only naming or reading in only one of the patient's languages. Of the 26 "language sites", only 3 produced any interferences in translation. All of these were located in frontal regions. Electrostimulation at these sites caused the patient to stop translating abruptly, but no language switching or other translation-related phenomenon was observed. No site was found that was involved only in translation and not other language tasks.Overall, in contrast to other language tasks, cortical structures of the convexity were rarely involved in translation. We suggest that translation interference could be more readily detected by subcortical stimulations. This spatial dissociation within the brain of translation function versus other language functions could explain the cases of dissociated language impairments observed in some bilingual patients with brain lesions. On a practical level, because the cortical sites found by translation tasks are few and related with other cortical language sites, we think that translation tasks provide little additional helpful information for cortical brain mapping in bilingual neurosurgical patients. © 2011 Elsevier Srl.

Sacko O.,UMR Unite 825 | Sacko O.,Universitaires Of Toulouse | Lauwers-Cances V.,Universitaires Of Toulouse | Brauge D.,Universitaires Of Toulouse | And 4 more authors.
Neurosurgery | Year: 2011

BACKGROUND: The use of an awake craniotomy in the treatment of supratentorial lesions is a challenge for both patients and staff in the operation theater. OBJECT: To assess the safety and effectiveness of an awake craniotomy with brain mapping in comparison with a craniotomy performed under general anesthesia. METHODS: We prospectively compared 2 groups of patients who underwent surgery for supratentorial lesions: those in whom an awake craniotomy with intraoperative brain mapping was used (AC group, n = 214) and those in whom surgery was performed under general anesthesia (GA group, n = 361, including 72 patients with lesions in eloquent areas). The AC group included lesions in close proximity to the eloquent cortex that were surgically treated on an elective basis. RESULTS: Globally, the 2 groups were comparable in terms of sex, age, American Society of Anesthesiologists score, pathology, size of lesions, quality of resection, duration of surgery, and neurological outcome, and different in tumor location and preoperative neurological deficits (higher in the AC group). However, specific data analysis of patients with lesions in eloquent areas revealed a significantly better neurological outcome and quality of resection (P <.001) in the AC group than the subgroup of GA patients with lesions in eloquent areas. Surgery was uneventful in AC patients and they were discharged home sooner. CONCLUSION: AC with brain mapping is safe and allows maximal removal of lesions close to functional areas with low neurological complication rates. It provides an excellent alternative to craniotomy under GA. Copyright © 2011 by the Congress of Neurological Surgeons.

Roux F.-E.,UMR Unite 825 | Roux F.-E.,Centres Hospitalo Universitaires | Jucla M.,UMR Unite 825 | Jucla M.,University of Toulouse II - Le Mirail | And 4 more authors.
PLoS ONE | Year: 2012

A fundamental issue in cognitive neuroscience is the existence of two major, sub-lexical and lexical, reading processes and their possible segregation in the left posterior perisylvian cortex. Using cortical electrostimulation mapping, we identified the cortical areas involved on reading either orthographically irregular words (lexical, "direct" process) or pronounceable pseudowords (sublexical, "indirect" process) in 14 right-handed neurosurgical patients while video-recording behavioral effects. Intraoperative neuronavigation system and Montreal Neurological Institute (MNI) stereotactic coordinates were used to identify the localization of stimulation sites. Fifty-one reading interference areas were found that affected either words (14 areas), or pseudo-words (11 areas), or both (26 areas). Forty-one (80%) corresponded to the impairment of the phonological level of reading processes. Reading processes involved discrete, highly localized perisylvian cortical areas with individual variability. MNI coordinates throughout the group exhibited a clear segregation according to the tested reading route; specific pseudo-word reading interferences were concentrated in a restricted inferior and anterior subpart of the left supramarginal gyrus (barycentre x = -68.1; y = -25.9; z = 30.2; Brodmann's area 40) while specific word reading areas were located almost exclusively alongside the left superior temporal gyrus. Although half of the reading interferences found were nonspecific, the finding of specific lexical or sublexical interferences is new evidence that lexical and sublexical processes of reading could be partially supported by distinct cortical sub-regions despite their anatomical proximity. These data are in line with many brain activation studies that showed that left superior temporal and inferior parietal regions had a crucial role respectively in word and pseudoword reading and were core regions for dyslexia. © 2012 Roux et al.

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