Presentation

Yara Odeh¹, Lara Pierce²; ¹York University

Executive functions (EF) are a set of cognitive skills that include self-regulation, inhibition of behaviours, attention switching, and working memory (Miyake et al., 2000). Prior research suggests that the experience of bilingualism can enhance EF, while clinical diagnoses, such as attention deficit hyperactivity disorder (ADHD), are associated with EF difficulties. Interactions between these variables – and underlying neural processes – are not well understood. Considerable research has found that bilinguals outperform monolinguals on certain EF tasks, including faster reaction times (RT) during monitoring, inhibition, and switching (Costa et al., 2009). Bilinguals also show enhanced neural processing during EF tasks, reflected by faster and larger N2 (inhibition, conflict monitoring) and P3 (response evaluation, attentional resource allocation) event-related potential responses compared to monolinguals (Botezatu et al., 2021; Moreno et al., 2008). Inversely, significant deficits in inhibition, shifting, and working memory have been observed in individuals with ADHD (Rubia et al., 2005). Electrophysiological studies have found reduced N2 amplitude during inhibition tasks in individuals with, compared to without, ADHD, suggesting differences in neural processing underlying EF (Liotti et al., 2007). Despite disparate EF profiles, little research has explored how bilingualism and ADHD interact to predict EF, and none at the neural level. One prediction is that positive effects of bilingualism on EF could buffer executive dysfunction for bilingual compared to monolingual individuals with ADHD. However, conflicting behavioural evidence exists. Some studies report slower RT and lower accuracy during EF tasks for bilinguals compared to monolinguals with ADHD (Bialystok et al., 2017; Mor et al., 2015), potentially due to the increased cognitive load that bilingualism may place on a disrupted EF system. However, studies were small and effects of bilingual age-of-onset, proficiency, and ADHD symptom severity – variables that could shape neural processes underlying EF – were not fully explored. The present study will address this gap by testing two groups of adult participants: bilinguals and monolinguals with ADHD. Diagnostic measures of ADHD and language assessments will be collected. Participants (n = 40) will complete EF tasks during electroencephalogram recording using a high-density 128-channel MagStim EGI system. Inhibition will be measured using a standard flanker task and set shifting using a Dimensional Change Card Sort task. Amplitude and latency of N2 and P3 components, and behavioural RT and accuracy, will be measured. If bilingualism supports EF, bilinguals with ADHD should show a) decreased latency and increased amplitude of the N2 and P3 components and b) faster RT and higher accuracy, compared to monolinguals with ADHD. If bilingualism does not support EF, the reverse pattern is expected. ADHD symptom severity, duration of bilingual exposure, and age of second language onset will be tested as predictors of neural and behavioural outcomes. With increasing bilingualism and ADHD diagnoses worldwide, understanding how these variables interact to drive EF is critical. The proposed study is the first to test neural mechanisms underlying interacting EF processes in these groups. It will further a mechanistic understanding of how individual differences in experience and neurodevelopment interact to shift EF.

Topic Areas: Disorders: Developmental, Multilingualism