TY - CHAP
T1 - Brain structure in bilingual compared to monolingual individuals with Alzheimer's Disease
T2 - Proof of concept
AU - Raji, Cyrus A.
AU - Meysami, Somayeh
AU - Merrill, David A.
AU - Porter, Verna R.
AU - Mendez, Mario F.
N1 - Publisher Copyright:
© 2024 IOS Press. All rights reserved. All rights reserved.
PY - 2024/2/20
Y1 - 2024/2/20
N2 - Background: Bilingualism is increasingly recognized as protective in persons at risk for Alzheimer's disease (AD). Objective: Compare MRI measured brain volumes in matched bilinguals versus monolinguals with AD. Methods: This IRB approved study analyzed T1 volumetric brain MRIs of patients with criteria-supported Probable AD. We identified 17 sequential bilinguals (any native language) with Probable AD, matched to 28 (62%) monolinguals on age and MMSE. Brain volumes were quantified with Neuroreader. Regional volumes as fraction of total intracranial volume (TIV) were compared between both groups, and Cohen's D effect sizes were calculated for statistically significant structures. Partial correlations between bilingualism and brain volumes adjusted for age, gender, and TIV. Results: Bilinguals had higher brain volumes in 37 structures. Statistical significance (p < 0.05) was observed in brainstem (t = 2.33, p = 0.02, Cohen's D= 0.71) and ventral diencephalon (t = 3.01, p = 0.004, Cohen's D= 0.91). Partial correlations showed statistical significance between bilingualism and larger volumes in brainstem (rp =0.37, p = 0.01), thalamus (rp = 0.31, p = 0.04), ventral diencephalon (rp = 0.50, p = 0.001), and pallidum (rp = 0.38, p = 0.01). Bilingualism positively correlated with hippocampal volume, though not statistically significant (rp = 0.17, p = 0.26). No brain volumes were larger in monolinguals. Conclusion: Bilinguals demonstrated larger thalamic, ventral diencephalon, and brainstem volumes compared to matched monolinguals with AD. This may represent a neural substrate for increased cognitive reserve in bilingualism. Future studies should extrapolate this finding into cognitively normal persons at risk for AD.
AB - Background: Bilingualism is increasingly recognized as protective in persons at risk for Alzheimer's disease (AD). Objective: Compare MRI measured brain volumes in matched bilinguals versus monolinguals with AD. Methods: This IRB approved study analyzed T1 volumetric brain MRIs of patients with criteria-supported Probable AD. We identified 17 sequential bilinguals (any native language) with Probable AD, matched to 28 (62%) monolinguals on age and MMSE. Brain volumes were quantified with Neuroreader. Regional volumes as fraction of total intracranial volume (TIV) were compared between both groups, and Cohen's D effect sizes were calculated for statistically significant structures. Partial correlations between bilingualism and brain volumes adjusted for age, gender, and TIV. Results: Bilinguals had higher brain volumes in 37 structures. Statistical significance (p < 0.05) was observed in brainstem (t = 2.33, p = 0.02, Cohen's D= 0.71) and ventral diencephalon (t = 3.01, p = 0.004, Cohen's D= 0.91). Partial correlations showed statistical significance between bilingualism and larger volumes in brainstem (rp =0.37, p = 0.01), thalamus (rp = 0.31, p = 0.04), ventral diencephalon (rp = 0.50, p = 0.001), and pallidum (rp = 0.38, p = 0.01). Bilingualism positively correlated with hippocampal volume, though not statistically significant (rp = 0.17, p = 0.26). No brain volumes were larger in monolinguals. Conclusion: Bilinguals demonstrated larger thalamic, ventral diencephalon, and brainstem volumes compared to matched monolinguals with AD. This may represent a neural substrate for increased cognitive reserve in bilingualism. Future studies should extrapolate this finding into cognitively normal persons at risk for AD.
KW - Alzheimer's disease
KW - Bilingual
KW - Brain structure
KW - Neuroreader
UR - http://www.scopus.com/inward/record.url?scp=85189576605&partnerID=8YFLogxK
U2 - 10.3233/AIAD230054
DO - 10.3233/AIAD230054
M3 - Chapter
AN - SCOPUS:85189576605
SN - 9781643684925
SP - 557
EP - 562
BT - Handbook of Prevention and Alzheimer's Disease
PB - IOS Press
ER -