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Bilingualism is associated with lower cognitive decline and with lower levels of AD biomarkers in a cognitively unaffected cohort
Author(s) -
Dauar Marina Tedeschi,
Picard Cynthia,
RosaNeto Pedro,
Breitner John,
Villeneuve Sylvia,
Poirier Judes
Publication year - 2021
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1002/alz.055044
Subject(s) - cohort , cognition , neuroscience of multilingualism , cognitive reserve , cognitive decline , psychology , dementia , medicine , cohort study , entorhinal cortex , clinical psychology , audiology , developmental psychology , disease , psychiatry , cognitive impairment , neuroscience , hippocampus
Abstract Background Speaking two or more languages has been shown to contribute to cognitive reserve and to delay the onset of Alzheimer’s disease (AD). However, little is known about the effect of bilingualism on the progression of AD biomarkers. In this study, we intended to investigate the effect of bilingualism on cognitive scores and on AD biomarkers in a cohort of cognitively unaffected individuals. Method We analyzed data from participants of the PREVENT‐AD cohort. This cohort comprises cognitively normal participants over the age of 55 who have a first degree relative with AD. Cognition was assessed with the RBANS scale, Tau burden was measured with [18F]‐AV1451 PET, and CSF biomarkers were measured with Innotest’s enzyme‐linked immunosorbent assay kit (Fujirebio, Ghent, Belgium). Analyses were performed comparing participants who speak one, two or three languages and comparing participants who speak one or more than one language. Result A total of 327 participants were included, with 89 that speak one language, 195 that speak two languages, and 43 that speak three languages. We found that participants who speak more than one language have significantly higher attention scores (p=0.041) (Fig. 1a) and total RBANS scores (p=0.021) (Fig 1b) than participants who speak only one language. Participants who speak two languages have a lower tau burden in the entorhinal cortex than participants who speak one language (p=0.047) (Fig. 2). For total Tau, participants who speak more than one language have lower CSF levels than participants who speak one language. This difference increases over time and becomes statistically significant on follow up visits 36 months (p=0.049) and 48 months (p= 0.031) (Fig 3a). Participants who speak more than one language have lower CSF levels of phospho‐Tau (p= 0.017) (Fig 3b), and neurofilament light (p=0.041)(Fig 3c) compared to participants who speak one language. Conclusion Our results show that bilingualism is associated not only with less cognitive decline, but also with lower levels of AD biomarkers in pre‐symptomatic AD.