Executive functioning during verbal fluency tasks in bilinguals: A systematic review.

Background: Bilingualism is widespread and being bilingual is more common than being monolingual. The lifelong practice bilinguals receive from managing two languages seems to lead to a cognitive benefit. Conversely, bilingualism seems to affect language ability negatively due to less use of each known language. Aims: This systematic review aims to summarize the results of the studies on the effect of bilingualism on executive functioning assessed by verbal fluency tasks. The verbal fluency task is a neuropsychological measure of lexical retrieval efficiency and executive functioning. Methods: The review was conducted according to the PRISMA statement through searches in the scientific databases PsycINFO, PsycARTICLES, MEDLINE, PubMed, Web of Science and SCOPUS. Studies included in this review had at least one bilingual and monolingual group, participants over 18 years and one verbal fluency task. Studies that considered bimodal bilingual, second language learners, trilingual or multilingual people, and clinical populations were excluded. A total of 38 studies were included in the systematic review. Main Contribution: Quantitative analysis of performance did not show significant differences between monolinguals and bilinguals. Qualitative results are mixed, and no definitive conclusions can be drawn about a bilingual advantage or disadvantage in the verbal fluency tasks. Conclusions: Normative data based on the monolingual population are not appropriate to test a bilingual population. It is necessary to take precautions in using this task, especially in clinical practice. WHAT THIS PAPER ADDS: What is already known on the subject: Bilingualism seems to lead to a cognitive benefit due to constantly monitoring the known languages to select the most suitable one for each interactional context and to affect language ability negatively due to less use of each known language but also to language ability negatively. What this paper adds to the existing knowledge: This systematic review summarizes the results of the studies on the effect of bilingualism on executive functioning assessed by verbal fluency tasks, a neuropsychological measure of lexical retrieval efficiency and executive functioning. What are the potential or actual clinical implications of this work?: Normative data based on the monolingual population are not appropriate to test a bilingual population. It is necessary to take precautions in using this task, especially in clinical practice. [ABSTRACT FROM AUTHOR]