Grey Matter Reshaping of Language-Related Regions Depends on Tumor Lateralization.

A brain tumor in the left hemisphere can decrease language laterality as assessed through fMRI. However, it remains unclear whether or not this decreased language laterality is associated with a structural reshaping of the grey matter, particularly within the language network. Here, we examine if the disruption of the language hubs exclusively affects the macrostructural properties of the contralateral homologues or whether it affects both hemispheres.

Grey matter reshaping of language-related regions depends on tumor lateralization.

A brain tumor in the left hemisphere can decrease language laterality as assessed with fMRI. However, it remains unclear whether or not this decreased language laterality is associated with a structural reshaping of the grey matter, particularly within the language network. Here, we examine if the disruption of language hubs exclusively affects macrostructural properties of contralateral homologues (as suggested by previous research), or whether it affects both hemispheres.

General principles governing the amount of neuroanatomical overlap between languages in bilinguals.

The literature has identified many important factors affecting the extent to which languages in bilinguals rely on the same neural populations in the specific brain region. The factors include the age of acquisition of the second language (L2), proficiency level of the first language (L1) and L2, and the amount of language exposure, among others. What is lacking is a set of global principles that explain how the many factors relate to the degree to which languages overlap neuroanatomically in bilinguals.

Organizing Variables Affecting fMRI Estimates of Language Dominance in Patients with Brain Tumors.

Numerous variables can affect the assessment of language dominance using presurgical functional magnetic resonance (fMRI) in patients with brain tumors. This work organizes the variables into confounding and modulating factors. Confounding factors give the appearance of changed language dominance.

Prior Neurosurgery Decreases fMRI Estimates of Language Laterality in Patients with Gliomas within Anterior Language Sites.

The impact of previous surgery on the assessment of language dominance with preoperative fMRI remains inconclusive in patients with recurrent brain tumors. Samples in this retrospective study included 17 patients with prior brain surgery and 21 patients without prior surgery (38 patients total; mean age 43.2, SD = 11.

Tumor location and reduction in functional MRI estimates of language laterality.

Objective: Brain tumors located close to the language cortex may distort functional MRI (fMRI)-based estimates of language dominance. The nature of this distortion, and whether this is an artifact of numerous confounders, remains unknown. The authors hypothesized tumor bias based on laterality estimates independent of confounders and that the effects are the greatest for tumors proximal to Broca's area.

Factors Modifying the Amount of Neuroanatomical Overlap between Languages in Bilinguals-A Systematic Review of Neurosurgical Language Mapping Studies.

Neurosurgery on individuals with lesions around language areas becomes even more complicated when the patient is bilingual. It is thus important to understand the principles that predict the likelihood of convergent versus separate neuroanatomical organization of the first (L1) and the second language (L2) in these individuals. We reviewed all English-language publications on neurosurgical language mapping in bilinguals before January 2020 in three databases (e.

Presurgical language fMRI: Technical practices in epilepsy surgical planning.

Little is known about how language functional MRI (fMRI) is executed in clinical practice in spite of its widespread use. Here we comprehensively documented its execution in surgical planning in epilepsy. A questionnaire focusing on cognitive design, image acquisition, analysis and interpretation, and practical considerations was developed.

Lateralizing language function with pre-operative functional magnetic resonance imaging in early proficient bilingual patients.

Research on bilinguals with brain lesions is complicated by high patient variability, making it difficult to find well-matched controls. We benefitted from a database of over 700 patients and conducted an analysis of pre-operative functional magnetic resonance imaging data to assess language dominance in 25 early, highly proficient Spanish-English bilinguals, and 25 carefully matched monolingual controls. Our results showed that early bilingualism is associated with greater bilateral hemispheric involvement, and monolingualism is associated with stronger left hemisphere lateralization (p=0.

Language system organization in a quadrilingual with a brain tumor: Implications for understanding of the language network.

In pre-neurosurgery language mapping it is critical to identify language-specific regions in multilingual speakers. We conducted pre-operative functional magnetic resonance imaging, and intraoperative language mapping in the unique case of a highly proficient quadrilingual with a left frontal brain tumor who acquired her second language at age 5, and her third and fourth languages at 15. We found a predominantly different organization in each language with only a few areas shared by all 4 languages.

Role of the Wada test and functional magnetic resonance imaging in preoperative mapping of language and memory: two atypical cases.

The Wada test is an invasive procedure used to determine cerebral memory and language dominance as well as risk of cognitive deficits following neurosurgery. However, the potential risks of Wada testing have led some to consider foregoing Wada testing in candidates for resective epilepsy surgery with right hemispheric seizure onset. We present two atypical cases in which the Wada test showed unexpected memory and language lateralization.