de Paula França Resende Elisa, Lara Vivian P, Santiago Ana Luisa C, Friedlaender Clarisse V, Rosen Howard J, Brown Jesse A, Cobigo Yann, Silva Lênio L G, Cruz de Souza Leonardo, Rincon Luciana, Grinberg Lea T, Maciel Francisca I P, Caramelli Paulo
Departamento de Clínica Médica Universidade Federal de Minas Gerais Belo Horizonte Brazil.
Global Brain Health Institute San Francisco California USA.
Alzheimers Dement (Amst). 2024 Sep 11;16(3):e12634. doi: 10.1002/dad2.12634. eCollection 2024 Jul-Sep.
The influence of hippocampal connectivity on memory performance is well established in individuals with high educational attainment. However, the role of hippocampal connectivity in illiterate populations remains poorly understood.
Thirty-five illiterate adults were administered a literacy assessment (Test of Functional Health Literacy in Adults [TOFHLA]), structural and resting state functional magnetic resonance imaging, and an episodic memory test (Free and Cued Selective Reminding Test). Illiteracy was defined as a TOFHLA score < 53. We evaluated the correlation between hippocampal connectivity at rest and both free recall and literacy scores.
Participants were mostly female (57.1%) and self-declared as being Black individuals (84.8%), with a median age of 50 years. The median TOFHLA literacy score was 28.0 [21.0; 42.5] out of 100 points and the median free recall score was 30.0 [26.2; 35] out of 48 points. The median gray matter volume of both the left and right hippocampi was 2.3 [2.1; 2.4] cm. We observed a significant connectivity between both hippocampi and the precuneus and the ventral medial prefrontal cortex. The right hippocampal connectivity positively correlated with the literacy scores (β = 0.58, = 0.008). There was no significant association between episodic memory and hippocampal connectivity. Neither memory nor literacy scores correlated with hippocampal gray matter volume.
Low literacy levels correlated with hippocampal connectivity in illiterate adults. The lack of association with memory scores might be associated with low brain reserve in this sample.
A significant link was found between health literacy and hippocampal connectivity.Enhanced hippocampus- ventromedial prefrontal cortex connectivity suggests potential cognitive reserve improvement.Higher cognitive reserve may protect against hippocampal atrophy and neurodegeneration.Health literacy improvements could help prevent cognitive impairment in illiterate populations.Study highlights importance of considering structural racism in brain connectivity research.
海马体连通性对记忆表现的影响在高学历个体中已得到充分证实。然而，海马体连通性在文盲群体中的作用仍知之甚少。
对35名成年文盲进行了一项识字能力评估（成人功能性健康识字测试[TOFHLA]）、结构和静息态功能磁共振成像，以及一项情景记忆测试（自由和提示选择性回忆测试）。文盲被定义为TOFHLA分数<53分。我们评估了静息状态下海马体连通性与自由回忆和识字分数之间的相关性。
参与者大多为女性（57.1%），自我宣称是黑人个体（84.8%），中位年龄为50岁。TOFHLA识字分数中位数为100分中的28.0[21.0；42.5]分，自由回忆分数中位数为48分中的30.0[26.2；35]分。左右海马体的灰质体积中位数均为2.3[2.1；2.4]立方厘米。我们观察到两个海马体与楔前叶和腹内侧前额叶皮层之间存在显著的连通性。右侧海马体连通性与识字分数呈正相关（β = 0.58，P = 0.008）。情景记忆与海马体连通性之间无显著关联。记忆分数和识字分数均与海马体灰质体积无关。
低识字水平与成年文盲的海马体连通性相关。与记忆分数缺乏关联可能与该样本中的低脑储备有关。
健康识字与海马体连通性之间发现了显著联系。海马体-腹内侧前额叶皮层连通性增强表明潜在的认知储备改善。更高的认知储备可能预防海马体萎缩和神经退行性变。提高健康识字水平有助于预防文盲群体的认知障碍。研究强调了在脑连通性研究中考虑结构性种族主义的重要性。
