Peitz Katharina, Bittner Nora, Heim Stefan, Caspers Svenja
Institute for Anatomy I, Medical Faculty & University Hospital Düsseldorf, Heinrich Heine University, Düsseldorf, Germany.
Institute of Neuroscience and Medicine (INM-1), Research Centre Jülich, Jülich, Germany.
Geroscience. 2025 Apr 8. doi: 10.1007/s11357-025-01639-0.
With aging, the hippocampal formation shows variable structural atrophy, which is associated with a decline in cognitive performance. Bilingualism is related to higher hippocampal gray matter volume (GMV), potentially representing a form of brain reserve in aging. However, the differential influence of bilingualism on hippocampal subregions remains unclear. Thus, we investigated GMV differences and differences in age-GMV relationships between mono- and bilinguals in the hippocampal formation and its subregions, hippocampus proper and subicular complex. We included 661 adults aged 19 to 85 years (257 monolinguals, 404 sequential bilinguals, predominantly native German speakers with variable second language background) from the population-based 1000BRAINS cohort. GMV differences in mono- vs. bilinguals were assessed for six regions of interest (hippocampal formation, hippocampus proper, and subicular complex; each left and right) using analyses of covariance. Effects of bilingualism on age-GMV relationships were investigated via moderation analyses. We found higher GMV in bilinguals in the bilateral subicular complex, while only a trend towards this effect existed for the hippocampal formation. Moderation analyses revealed similar age-GMV relationships between mono- and bilinguals for all regions of interest. Higher GMV in bilinguals' hippocampal formation seems specifically attributable to the subicular complex rather than the hippocampus proper. With similar age-GMV relationships for mono- and bilinguals, bilingual brain reserve in the subicular complex may persist over time. This may be particularly beneficial since subicular atrophy has previously been associated with higher risk for dementia. Altogether, a differential impact of bilingualism on hippocampal subregions has been demonstrated.
随着年龄增长，海马结构会出现不同程度的萎缩，这与认知能力下降有关。双语能力与较高的海马灰质体积（GMV）相关，这可能代表了衰老过程中一种大脑储备形式。然而，双语对海马亚区的不同影响仍不清楚。因此，我们研究了单语者和双语者在海马结构及其亚区（海马本部和下托复合体）的GMV差异以及年龄与GMV关系的差异。我们纳入了基于人群的1000BRAINS队列中的661名19至85岁的成年人（257名单语者，404名顺序双语者，主要是母语为德语、第二语言背景各异）。使用协方差分析评估单语者和双语者在六个感兴趣区域（海马结构、海马本部和下托复合体；左右各一个）的GMV差异。通过调节分析研究双语能力对年龄与GMV关系的影响。我们发现双语者双侧下托复合体的GMV较高，而海马结构仅存在这种效应的趋势。调节分析显示，单语者和双语者在所有感兴趣区域的年龄与GMV关系相似。双语者海马结构中较高的GMV似乎特别归因于下托复合体，而非海马本部。由于单语者和双语者的年龄与GMV关系相似，下托复合体中的双语大脑储备可能会随着时间持续存在。这可能特别有益，因为此前下托萎缩与较高的痴呆风险相关。总之，双语对海马亚区有不同影响已得到证实。
