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Query: UMLS:C0017638 (glioma)
 30,880 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Functional neuroimaging has improved pre-planning of surgery in eloquent cortical areas, but remains unable to map white matter. Thus, tumour resection in functional subcortical regions still presents a high risk of sequelae. The authors successfully used intraoperative electrical stimulations to perform subcortical language pathway mapping in order to avoid postoperative definitive deficit, and correlated these functional findings with the anatomical location of the eloquent bundles detected using postoperative MRI. At the same time, this also improved knowledge of fibre connectivity. Thirty patients harbouring a cortico-subcortical low-grade glioma in the left dominant hemisphere were operated on whilst awake using intraoperative electrical functional mapping during surgical resection. Language cortical sites and subcortical pathways were clearly identified and preserved in the 30 cases. The anatomo-functional correlations between data obtained using intraoperative subcortical mapping and postoperative MRI revealed the existence in all patients of common pathways which seem essential to language. This was shown by inducing reproducible speech disturbances during stimulations as follows: the subcallosal fasciculus (initiation disorders), the periventricular white matter (dysarthria), the arcuate fasciculus and the insular connections (anomia). Clinically, all patients except three presented a transient postoperative dysphasia, which resolved within 3 months. On control MRI, 14 resections were total and 16 subtotal due to infiltration of functional bundles described above. It is recommended that the combination of the techniques as described could prove ideal for future non-invasive reliable subcortical mapping both in healthy volunteers and in patients harbouring a (cortico)subcortical lesion in order to optimize surgical pre-planning.
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PMID:Intraoperative mapping of the subcortical language pathways using direct stimulations. An anatomo-functional study. 1183 4

Although the role of the premotor cortex (PMC) was widely studied in motor function, very few data are currently available about the participation of this structure in language. We report a series of 25 right-handed patients harboring a low-grade glioma near or within the left dominant PMC, operated on under local anesthesia with intraoperative real-time sensorimotor and language mappings using electrical stimulations all along the resection. Language tasks consisted of counting and picture naming (preceded by the reading of a short sentence). Stimulations of the left PMC induced transient speech disturbances in all patients, with disruption of both counting and reading/naming during stimulation of the ventral PMC--due to elicitation of an anarthria--while generating an anomia during stimulation of the dorsal PMC. Moreover, corresponding subcortical pathways generated the same language disorders as at the cortical level when stimulated. Eloquent structures were systematically preserved, allowing the avoidance of definitive postoperative deficit. These findings suggest first that the left dominant PMC seems to play a major role in language and second that this structure could have a well-ordered functional organization, namely with the ventral PMC, which might be involved in planification of articulation, and the dorsal PMC, which might be involved in the naming network.
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PMID:The role of dominant premotor cortex in language: a study using intraoperative functional mapping in awake patients. 1468 96

We performed a cortico-subcortical language electrical mapping, using a picture naming task and a semantic test of association, during resection of a left posterior temporal glioma in an awake patient. Two discrete naming sites were identified in the posterior part of the left superior temporal gyrus, plus a third distinct site between the two previous areas, inducing specific comprehension disorders without anomia when stimulated. After resection, white matter stimulation elicited anomia without comprehension disorder. We suggest the existence of distinct naming and comprehension systems, which can explain the possibility of a double dissociation aphasic syndrome: one with normal undertanding but naming error, reflecting post-semantic problems of access to the phonological form; the other with correct naming but without normal comprehension, testifying to a direct non-semantic pathway for naming.
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PMID:Double dissociation between picture naming and comprehension: an electrostimulation study. 1510 56

Although advances in diffusion tensor imaging have enabled us to better study the anatomy of the inferior longitudinal fasciculus (ILF), its function remains poorly understood. Recently, it was suggested that the subcortical network subserving the language semantics could be constituted, in parallel with the inferior occipitofrontal fasciculus, by the left ILF, joining the posterior occipitotemporal regions to the temporal pole, then relayed by the uncinate fasciculus connecting the anterior temporal pole to the frontobasal areas. Nevertheless, this hypothesis was solely based on neurofunctional imaging, allowing a cortical mapping but with no anatomofunctional information regarding the white matter. Here, we report a series of 12 patients operated on under local anaesthesia for a cerebral low-grade glioma located within the left temporal lobe. Before and during resection, we used the method of intraoperative direct electrostimulation, enabling us to perform accurate and reliable anatomofunctional correlations both at cortical and subcortical levels. In order to map the ILF. Using postoperative MRI, we correlated these functional findings with the anatomical locations of the sites where language disturbances were elicited by stimulations, both at cortical and subcortical levels. Our goal was to study the potential existence of parallel and distributed language networks crossing the left dominant temporal lobe, subserved by distinct subcortical pathways--namely the inferior occipitofrontal fasciculus and the ILF. Intraoperative stimulation of the anterior and middle temporal cortex elicited anomia in four patients. At the subcortical level, semantic paraphasia were induced in seven patients during stimulation of the inferior occipitofrontal fasciculus, and phonological paraphasia was generated in seven patients by stimulating the arcuate fasciculus. Interestingly, subcortical stimulation never elicited any language disturbances when performed at the level of the ILF. In addition, following a transient postoperative language deficit, all patients recovered, despite the resection of at least one part of the ILF, as confirmed by control MRI. On the basis of these results, we suggest that the "semantic ventral stream" could be constituted by at least two parallel pathways within the left dominant temporal lobe: (i) a direct pathway, the inferior occipitofrontal fasciculus, that connects the posterior temporal areas and the orbitofrontal region, crucial for language semantic processing, since it elicits semantic paraphasia when stimulated; (ii) and also possibly an indirect pathway subserved by the ILF, not indispensable for language, since it can be compensated both during stimulation and after resection.
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PMID:Does the left inferior longitudinal fasciculus play a role in language? A brain stimulation study. 1726 96

We report on a 12-years-old boy with glioma of the septum pellucidum which invaded and infiltrated the adjacent structures including neocortical commissures. Neuropsychological evaluation revealed the loss of interhemispheric integration and hemisphere dysconnection syndrome. Our patient demonstrated left-sided ideo-motor apraxia to verbal commands and left-sided agrafia, being unable to copy, write to dictation and formulate his own sentences with the left hand. He partly failed in attempts to name or describe objects out of sight in the left hand and showing an unilateral tactile anomia. The patient performed the block-design-test better with the left hand than the right hand, and demonstrated a right-sided constructive apraxia. He had extinction of his left ear on dichotic listening, despite a normal audiogram in both ears. Because of progressive defects of visual function, a tachistoscoping testing was not performed. There was no evidence of the alien hand syndrome, reported earlier. The general dysconnection syndrome caused by lesion of the corpus callosum, was associated with cognitive dysfunctions. Attention, memory and speech disorders were attributed to the progressive extra-callosal cerebral neoplastic lesion. The neurosurgical treatment was performed by transcallosal anterior approach. On neuropsychological retesting, 4 months later symptoms of hemisphere dysconnection were stabilized.
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PMID:[Dysconnection syndrome in a boy with tumorous lesion of corpus callosum]. 1797 75

We have studied the configuration of the cortico-subcortical language networks within the right hemisphere (RH) in nine left-handers, being operated on while awake for a cerebral glioma. Intraoperatively, language was mapped using cortico-subcortical electrostimulation, to avoid permanent deficit. In frontal regions, cortical stimulation elicited articulatory disorders (ventral premotor cortex), anomia (dorsal premotor cortex), speech arrest (pars opercularis), and semantic paraphasia (dorsolateral prefrontal cortex). Insular stimulation generated dysarthria, parietal stimulation phonemic paraphasias, and temporal stimulation semantic paraphasias. Subcortically, the superior longitudinal fasciculus (inducing phonological disturbances when stimulated), inferior occipito-frontal fasciculus (eliciting semantic disturbances during stimulation), subcallosal fasciculus (generating control disturbances when stimulated), and common final pathway (inducing articulatory disorders during stimulation) were identified. These cortical and subcortical structures were preserved, avoiding permanent aphasia, despite a transient immediate postoperative language worsening. Both intraoperative results and postsurgical transitory dysphasia support the major role of the RH in language in left-handers, and provide new insights into the anatomo-functional cortico-subcortical organization of the language networks in the RH-suggesting a "mirror" configuration in comparison to the left hemisphere.
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PMID:Cortico-subcortical organization of language networks in the right hemisphere: an electrostimulation study in left-handers. 1870 80

Contemporary clinical and basic neuroscience studies have increasingly implicated the anterior temporal lobe regions, bilaterally, in the formation of coherent concepts. Mounting convergent evidence for the importance of the anterior temporal lobe in semantic memory is found in patients with bilateral anterior temporal lobe damage (e.g. semantic dementia), functional neuroimaging and repetitive transcranial magnetic stimulation studies. If this proposal is correct, then one might expect patients with anterior temporal lobe resection for long-standing temporal lobe epilepsy to be semantically impaired. Such patients, however, do not present clinically with striking comprehension deficits but with amnesia and variable anomia, leading some to conclude that semantic memory is intact in resection for temporal lobe epilepsy and thus casting doubt over the conclusions drawn from semantic dementia and linked basic neuroscience studies. Whilst there is a considerable neuropsychological literature on temporal lobe epilepsy, few studies have probed semantic memory directly, with mixed results, and none have undertaken the same type of systematic investigation of semantic processing that has been conducted with other patient groups. In this study, therefore, we investigated the semantic performance of 20 patients with resection for chronic temporal lobe epilepsy with a full battery of semantic assessments, including more sensitive measures of semantic processing. The results provide a bridge between the current clinical observations about resection for temporal lobe epilepsy and the expectations from semantic dementia and other neuroscience findings. Specifically, we found that on simple semantic tasks, the patients' accuracy fell in the normal range, with the exception that some patients with left resection for temporal lobe epilepsy had measurable anomia. Once the semantic assessments were made more challenging, by probing specific-level concepts, lower frequency/more abstract items or measuring reaction times on semantic tasks versus those on difficulty-matched non-semantic assessments, evidence of a semantic impairment was found in all individuals. We conclude by describing a unified, computationally inspired framework for capturing the variable degrees of semantic impairment found across different patient groups (semantic dementia, temporal lobe epilepsy, glioma and stroke) as well as semantic processing in neurologically intact participants.
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PMID:Semantic memory is impaired in patients with unilateral anterior temporal lobe resection for temporal lobe epilepsy. 2228 82

The aim of this study was to investigate the method and significance of the application of direct electrical stimulation (DES) to the brain mapping of language functions during glioma surgery. A retrospective analysis of clinical data was performed for 91 cases of brain functional area glioma surgery under DES from January 2003 until January 2012. Following cortical electrical stimulation, 88 patients exhibited seizures involving facial or hand movements and 91 cases experienced language disorders such as counting interruption, naming errors or anomia. The most commonly observed areas of counting interruption were distributed on the posterior part of the left anterior central gyrus (47.7%), the operculum of the left inferior frontal gyrus (24.4%) and the triangular part of the left inferior frontal gyrus (12.8%). Postoperative magnetic resonance imaging demonstrated that overall excision was achieved in 53 cases and sub-overall excision was performed in 31 cases. A total of 42 cases (46.2%) exhibited no postoperative neurological dysfunction, 39 cases (42.9%) exhibited brief language dysfunction, 27 cases (29.7%) experienced brief limb movement disorder, and one case appeared to have permanent neurological dysfunction. DES was indicated to be a reliable and noninvasive method for the intraoperative positioning of language areas, and was able to resect gliomas in the language area with maximal safety.
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PMID:Glioma localization and excision using direct electrical stimulation for language mapping during awake surgery. 2613 23

Chinese processing has been suggested involving distinct brain areas from English. However, current functional localization studies on Chinese speech processing use mostly "indirect" techniques such as functional magnetic resonance imaging and electroencephalography, lacking direct evidence by means of electrocortical recording. In this study, awake craniotomies in 66 Chinese-speaking glioma patients provide a unique opportunity to directly map eloquent language areas. Intraoperative electrocortical stimulation was conducted and the positive sites for speech arrest, anomia, and alexia were identified separately. With help of stereotaxic neuronavigation system and computational modeling, all positive sites elicited by stimulation were integrated and a series of two- and three-dimension Chinese language probability maps were built. We performed statistical comparisons between the Chinese maps and previously derived English maps. While most Chinese speech arrest areas located at typical language production sites (i.e., 50% positive sites in ventral precentral gyrus, 28% in pars opercularis and pars triangularis), which also serve English production, an additional brain area, the left middle frontal gyrus (Brodmann's areas 6/9), was found to be unique in Chinese production (P < 0.05). Moreover, Chinese speakers' inferior ventral precentral gyrus (Brodmann's area 6) was used more than that in English speakers. Our finding suggests that Chinese involves more perisylvian region (extending to left middle frontal gyrus) than English. This is the first time that direct evidence supports cross-cultural neurolinguistics differences in human beings. The Chinese language atlas will also helpful in brain surgery planning for Chinese-speakers.
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PMID:Direct evidence from intraoperative electrocortical stimulation indicates shared and distinct speech production center between Chinese and English languages. 2635 Oct 94

The role of the left inferior longitudinal fasciculus (ILF) in language processing has been called into question by recent studies showing that disruption of this tract in glioma patients did not necessarily lead to detrimental effects on spoken language, especially on picture naming. Here we show that disruption of the left ILF with axonal stimulation in patients undergoing an "awake" surgery for a slow-growing tumour systematically induces pure anomia, but only when the temporal pole (TP) is not infiltrated by the tumour. This finding not only confirms that the ILF plays a role in lexical retrieval in normal circumstances but also suggests that the information conveyed by this tract can be rerouted to alternative pathways when the TP is widely lesioned and abandons its function. This conclusion is further supported by the case of a patient who developed a long-lasting anomic aphasia after a surgically preplanned interruption of the ILF.
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PMID:Functional compensation of the left inferior longitudinal fasciculus for picture naming. 2987 63


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