Effectiveness of four different clinical fMRI paradigms for preoperative regional determination of language lateralization in patients with brain tumors

Abstract

SWG and R are sufficient for the determination of lateralization in expressive language areas, whereas new semantic or receptive paradigms need to be designed for an improved assessment of lateralization in receptive language areas.

Role of Semantic Paradigms for Optimization of Language Mapping in Clinical fMRI Studies

“…Furthermore, contrary to phonologic processing studies reporting lateralized activation in receptive language areas, the semantic component of the active task (antonym versus nonantonym) explains the bilateral pattern of activation in our group of volunteers. 4 We found, in our study, greater activation for Sentence Completion in the left MTG compared with Visual Antonym Pair and Auditory Antonym Pair but not compared with Noun-Verb Association, and these findings could be attributed to the higher level of lexical-semantic processing required for Sentence Completion and Noun-Verb Association. 19 Instead Sentence Completion activation was stronger than Noun-Verb Association and Visual Antonym Pair in the right MTG and STG, confirming the role of the right hemisphere in semantic tasks involving executive processing.…”

“…However, the assessment of language lateralization by fMRI can be affected by many factors, including task selection, ROIs used for lateralization index (LI) computation, and statistical thresholding. 4,5 For all of the above-mentioned reasons, fMRI for language mapping is still not universally accepted as a standard of care for presurgical planning. In light of the recently developed language models and to contribute to the effort to establish effective protocols for language fMRI, we designed this study to determine which paradigm or combination of paradigms provides an adequate and streamlined protocol for comprehensive language mapping in clinical fMRI studies.…”

Avaliação de linguagem por ressonância magnética funcional em pacientes com epilepsia associada à esclerose mesial temporal unilateral: correlação com avaliação clínica de linguagem

“…Ambos procedimentos mostram que a representação atípica da linguagem ocorre em, aproximadamente, 5% da população saudável e em torno de 20% dos pacientes cuja zona epileptogênica se localiza no HE (Springer;Hammeke, 1999;Janszky et al, 2003;Weber et al, 2006;Rathore et al, 2009 ( Helmstaedter et al, 1997;Binder et al, 2008;Bell et al, 2011b Ao injetar-se o anestésico do lado contralateral à lesão, avalia-se a capacidade do hemisfério lesado em ainda exercer estas funções (Loring, 2010;Hamberger;Cole, 2011;Hayman-Abello, 2012 (Loddenkemper et al, 2007). Ademais, o teste de Wada é desconfortável para o paciente e seu custo é bastante elevado (Zacà et al, 2012).…”

“…Apesar de suas desvantagens, o teste de Wada ainda é considerado a técnica padrão-ouro para avaliar a representação hemisférica da linguagem pré-operatória (Zacà et al, 2012).…”

“…Na maioria dos estudos encontrados na literatura, o paradigma GP é mais parecido com sua versão clínica: paciente tem 20 a 30 segundos para gerar mentalmente "covert") o maior número possível de palavras para determinada letra na condição ativa, e, na condição controle, tem 20 a 30 segundos para repetir, também mentalmente, uma palavra sem sentido (p.ex. : "b " (Rosazza et al, 2013) ou ficar em silêncio (Gaillard et al, 2002;Zacà et al, 2012). et al, 2013).…”