Candice Steffen Holderbaum

Lexical-semantic processing in the semantic priming paradigm in aphasic patients

There is evidence that the explicit lexical-semantic processing deficits which characterize aphasia may be observed in the absence of implicit semantic impairment. The aim of this article was to critically review the international literature on lexical-semantic processing in aphasia, as tested through the semantic priming paradigm. Specifically, this review focused on aphasia and lexical-semantic processing, the methodological strengths and weaknesses of the semantic paradigms used, and recent evidence from neuroimaging studies on lexical-semantic processing. Furthermore, evidence on dissociations between implicit and explicit lexical-semantic processing reported in the literature will be discussed and interpreted by referring to functional neuroimaging evidence from healthy populations. There is evidence that semantic priming effects can be found both in fluent and in non-fluent aphasias, and that these effects are related to an extensive network which includes the temporal lobe, the pre-frontal cortex, the left frontal gyrus, the left temporal gyrus and the cingulated cortex.

Heterogeneity in semantic priming effect with a lexical decision task in patients after left hemisphere stroke

ABSTRACT Investigations on the semantic priming effect (SPE) in patients after left hemisphere (LH) lesions have shown disparities that may be explained by the variability in performance found among patients. The aim of the present study was to verify the existence of subgroups of patients after LH stroke by searching for dissociations between performance on the lexical decision task based on the semantic priming paradigm and performance on direct memory, semantic association and language tasks. All 17 patients with LH lesions after stroke (ten non-fluent aphasics and seven non aphasics) were analyzed individually. Results indicated the presence of three groups of patients according to SPE: one exhibiting SPE at both stimulus onset asynchronies (SOAs), one with SPE only at long SOA, and another, larger group with no SPE.

Estudo comparativo do acesso semântico no processamento visual de palavras entre brasileiros monolíngues e chineses multilíngues falantes do português do Brasil como língua estrangeira

O priming semântico e uma forma de avaliar o processamento semântico de palavras. Se a semântica e um importante fator contribuinte no reconhecimento visual de palavras, surge a questao de se chineses multilingues (mandarin como L1 e ingles como L2), que estao aprendendo o portugues como L3, podem se beneficiar do contexto semântico em tarefa de decisao lexical na Lingua Portuguesa, comparado aos controles (brasileiros universitarios e criancas). Alem de comparar a magnitude do efeito de priming semântico entre a amostra de chineses e de brasileiros, objetivou-se investigar nos chineses a relacao entre o desempenho no experimento de priming semântico e na tarefa de consciencia fonologica, ambos na lingua portuguesa. Participaram do estudo 40 universitarios chineses multilingues, 31 universitarios brasileiros e 26 criancas de 3a serie. Houve efeito de priming semântico nos chineses e nos brasileiros, universitarios e criancas, ou seja, respostas mais rapidas na condicao com prime relacionado do que na condicao com prime nao relacionado. Nao houve diferencas significativas na magnitude do efeito entre os grupos de adultos, mas as criancas apresentaram maior magnitude de efeito do que os chineses. Considerando apenas o grupo de chineses, nao houve correlacao entre os escores na tarefa de decisao lexical no paradigma de priming semântico e a avaliacao da consciencia fonologica. Chineses parecem ter acessado o significado dos primes apresentados visualmente na Lingua Portuguesa, nao se diferenciando dos brasileiros adultos e criancas .