Influence of bilingualism on neurocognitive functioning: Relation to educational attainment and Apolipoprotein E-4 status

Previous studies have consistently supported a protective effect of bilingualism against executive and global neurocognitive decline, however much remains to be elucidated regarding the modifying influence of other ecological and genetic risk factors on these relationships. A primary aim of this study was to extend previous findings suggesting a protective effect of bilingualism against neurocognitive decline to a previously unstudied bilingual sample of Hispanics and non-Hispanic Whites. Furthermore, this investigation intended to examine the respective influences of educational attainment and Apolipoprotein-E-4 (ApoE-4) status on this association. Bilingualism was found to significantly and positively influence executive and global neurocognitive functioning across ages among non-Hispanic Whites, however this protective effect only remained significant after controlling for quality of education but not years of education. ApoE-4 negative bilinguals exhibited better executive functioning across ages compared to monolingual non-carriers, but no significant bilingual advantage was observed among ApoE-4 carriers. This study advances knowledge on the relationships between bilingualism, educational attainment, ApoE-4 status, and neurocognitive functioning in diverse subgroups, and highlights the importance of accounting for the complex interplay of other risk factors when seeking to explain the bilingualism effect. Implications for theory, practice, and research are discussed.