Poster D54, Wednesday, August 21, 2019, 5:15 – 7:00 pm, Restaurant Hall
Effects of bilingualism and lifestyle choices on the neural indices of cognitive control in older adults
Caitlin E. O'Riordan1, Gretta Bunn1, Megan Woodruff1, Debra L. Mills1;1Bangor University, Wales.
Older adult bilinguals often outperform monolinguals on non-verbal tasks of executive functioning, including measures of inhibitory control, task switching and working memory. Some research suggests bilingualism can even delay the onset of symptoms associated with dementia. Bialystok argues that the use of domain-general executive functions to control and suppress language results in a “bilingual advantage” on tasks of executive function.However, a bilingual advantage is not consistently observed. For example, it is not observed in behavioural measures of executive function nor in the delay of the onset of dementia in Welsh-English older adults. The factors associated with the presence or absence of the bilingual advantage are not well understood. The present study examined how age, several lifestyle factors, and facets of bilingualism such as age of second language (L2) acquisition, percentage of L2 daily use and L2 proficiency affected brain activity associated with cognitive control. We employed the event-related potential (ERP) technique with a visual Go/NoGo paradigm. The EEG from adults aged 65 to 85 years was recorded as individuals detected a cartoon target and executed a manual response (Go stimuli) or withheld the button press to any other characters (NoGo stimuli). Previous research suggests that conflict resolution associated with withholding a response to NoGo stimuli is linked to larger N2 amplitudes for young adult bilinguals relative to monolinguals. Moreover, it has been reported that older adults have attenuated N2 amplitudes in comparison to younger adults on a visual Go/NoGo paradigm. In the current research, participants included monolingual speakers of English (N =16), and Welsh-English bilinguals who reported using their L2 at least 25% of their daily life (N = 20). Participants also completed a questionnaire on alcohol intake, smoking, sleeping and exercise habits, which was used to generate a lifestyle score. Monolinguals and bilinguals did not differ in terms of SES, lifestyle score, age and scores on the Montreal Cognitive Assessment (MoCA).Monolinguals and bilinguals achieved comparable accuracy rates and reaction times. However, analysis of the brain activity associated with conflict resolution revealed significant differences. Consistent with previous research, monolinguals over age 65 did not show larger N2 amplitudes to the NoGo than Go trials. In contrast, for bilinguals, success in withholding a prepotent manual response (NoGo trials) was associated with significantly larger mean amplitudes for the N2 relative to Go trials. Analysis of questionnaire responses revealed a significant correlation with lifestyle score and N2 effect for bilinguals, wherein an increased N2 effect (larger NoGo-N2 relative to Go-N2) was correlated with a healthier lifestyle score. This correlation was not present for monolinguals.These findings suggest that bilinguals who utilise their L2 at least 25% of the time show patterns of brain activity associated with conflict resolution similar to those reported for younger adults. Lifestyle factors such as alcohol intake, smoking frequency, sleep quality and exercise interact with the advantage elicited by bilingualism. The results have implications for targeted interventions to stimulate second language use in older adults.
Themes: Multilingualism, Control, Selection, and Executive Processes
Method: Electrophysiology (MEG/EEG/ECOG)