Abstract
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.
Original language | English |
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Title of host publication | Handbook of Prevention and Alzheimer's Disease |
Publisher | IOS Press |
Pages | 557-562 |
Number of pages | 6 |
ISBN (Electronic) | 9781643684932 |
ISBN (Print) | 9781643684925 |
DOIs | |
State | Published - Feb 20 2024 |
Externally published | Yes |
Keywords
- Alzheimer's disease
- Bilingual
- Brain structure
- Neuroreader