Bilingualism, executive control, and age at diagnosis among people with early‐stage A lzheimer's disease in W ales

• Published in: Journal of neuropsychology 2016-09, Vol.10 (2), p.163-185
• Main Authors: Clare, Linda, Whitaker, Christopher J., Craik, Fergus I. M., Bialystok, Ellen, Martyr, Anthony, Martin‐Forbes, Pamela A., Bastable, Alexandra J. M., Pye, Kirstie L., Quinn, Catherine, Thomas, Enlli M., Gathercole, Virginia C. Mueller, Hindle, John V.
• Format: Article
• Language: English
• ISSN: 1748-6645; 1748-6653
• DOI: 10.1111/jnp.12061

The observation of a bilingual advantage in executive control tasks involving inhibition and management of response conflict suggests that being bilingual might contribute to increased cognitive reserve. In support of this, recent evidence indicates that bilinguals develop A lzheimer's disease ( AD ) later than monolinguals, and may retain an advantage in performance on executive control tasks. We compared age at the time of receiving an AD diagnosis in bilingual W elsh/ E nglish speakers ( n  = 37) and monolingual E nglish speakers ( n  = 49), and assessed the performance of bilinguals ( n  = 24) and monolinguals ( n  = 49) on a range of executive control tasks. There was a non‐significant difference in age at the time of diagnosis, with bilinguals being on average 3 years older than monolinguals, but bilinguals were also significantly more cognitively impaired at the time of diagnosis. There were no significant differences between monolinguals and bilinguals in performance on executive function tests, but bilinguals appeared to show relative strengths in the domain of inhibition and response conflict. Bilingual W elsh/ E nglish speakers with AD do not show a clear advantage in executive function over monolingual E nglish speakers, but may retain some benefits in inhibition and management of response conflict. There may be a delay in onset of AD in W elsh/ E nglish bilinguals, but if so, it is smaller than that found in some other clinical populations. In this W elsh sample, bilinguals with AD came to the attention of services later than monolinguals, and reasons for this pattern could be explored further.