White matter differences in bilingual and monolingual children: An ABCD data study
Poster D54 in Poster Session D with Social Hour, Friday, October 7, 5:30 - 7:15 pm EDT, Millennium Hall
Juliana Ronderos1,2, Jennifer Zuk1, Arturo E. Hernandez2, Kelly A. Vaughn3; 1Boston University, 2University of Houston, 3University of Texas Health Sciences Center at Houston
Emerging evidence suggests that brain structure changes not only result from maturation but also through environmental experience, including the active use/exposure to two languages. Limited studies have examined the structural impacts of bilingualism with inconclusive and mixed findings due to small sample sizes and assessments at various stages of development. The Adolescent Brain Cognitive Development (ABCD) Study dataset provides an opportunity to investigate structural differences associated with bilingualism, leveraging neuroimaging and behavioral data from a large sample of adolescents. We used the ABCD baseline release to compare white matter (WM) organization of bilingual and monolingual children (ages 9-10). We identified bilingual children using parental and youth questionnaires for children exposed/using another language equally or more often than English. First, we compared WM organization as indicated by fractional anisotropy (FA) values in prominent language-related WM tracts between bilinguals and monolinguals using multiple regressions, controlling for age, sex, nonverbal IQ, pubertal status, handedness, parental education, and household income. We found significant differences between bilinguals and monolinguals in 18 of 27 WM tracts, including bilateral language network tracts, and the splenium and genu of the corpus callosum. FA values were greater across all tracts for monolinguals compared to bilinguals. These results replicate findings in some studies of WM organization in bilingual children, but using a much larger sample of children. However, these findings differ from what has been observed in WM comparisons of bilingual and monolingual adults, which tend to indicate higher FA values among bilinguals relative to monolingual adults. We then explored the impact each of the covariates in our regression models on FA values for monolinguals and bilinguals separately. We found that, for this group of children, handedness, pubertal status and household income did not significantly impact FA values within either the bilingual or the monolingual group. Further, in the bilingual group we found no significant effects of sex, non-verbal IQ and English vocabulary levels on FA values while there were significant differences as a result of this covariates within the monolingual group in various WM tracts. Finally, we found that there were significant effects of age and maternal education on FA values in both the bilingual and monolingual groups. However, although both age and maternal education were positively related to increased FA values in both groups, the amount of the impact and the WM tracts where there were significant differences as a result of age and maternal education varied in the bilingual and monolingual groups. Further studies examining structural changes longitudinally in monolingual and bilingual children are necessary to understand how bilingualism (and other environmental factors) shape neuroanatomy in development.
Topic Areas: Multilingualism, Development