Poster D11, Friday, August 17, 4:45 – 6:30 pm, Room 2000AB
Electrophysiological Effects of Bilingualism and Aging on Working Memory
Cassandra Morrison1,2, Farooq Kamal1,2, Giovanna Busa1,2, Vanessa Taler1,2, Jason Steffener1;1University of Ottawa, 2Bruyère Research Institute
Introduction: Being bilingual (fluent in two languages) appears to confer a benefit in certain aspects of cognitive functioning relative to being monolingual (fluent in only one language). Differences between monolinguals and bilinguals may be more evident in older than younger adults due to age-related cognitive decline. However, little research has examined differences in working memory between younger and older monolinguals and bilinguals. The current study utilizes electroencephalography (EEG) to examine working memory differences between younger and older bilinguals and monolinguals. Methods: To date, 78 participants have taken part in the study: 22 monolingual and 22 bilingual younger adults (aged 18-30); and 10 bilingual and 24 monolingual older adults (65+). The participants first underwent neuropsychological testing to characterize cognitive functioning and working memory capacity and processing. They then completed a Sternberg task while their EEG, reaction time, and accuracy were recorded. Results: Analysis of these preliminary data found no effects of bilingualism on accuracy or reaction time (p >.05 in all analyses). Overall, older adults responded more slowly than young adults at all three levels of task difficulty (p<.001), although accuracy did not differ between groups (p=.15). When examining frontal and central regions, both the P300 and N200 were influenced by age and language. Younger adults exhibited larger (more negative) N200 amplitudes relative to older adults (p=.002), but smaller P300 amplitudes compared to older adults (p<.001). Monolinguals exhibited a larger N200 than bilinguals (p=.016), but smaller P300 amplitudes compared to bilinguals (p=.006). Conclusions: These results indicate that ERPs are more sensitive than behavioral measures to cognitive differences related to age and bilingualism. The ERP findings suggest that bilinguals may require less effort to discriminate whether the test array matches the memory array (as shown by less negative N200s), and more resources available to allocate to task completion (larger P300s). Interpreting the age-related findings in the same way, it would also seem that older adults have more resources available relative to younger adults and require less effort to discriminate whether the test array matches the memory array. However, the increased amplitude in frontal regions in older relative to younger adults is consistent with the posterior to anterior shift (PASA) in aging. This increased activity in the frontal regions suggests that older adults depend more on frontal regions to complete the task.
Topic Area: Phonology and Phonological Working Memory