Harvard Graduate School of Education, Cambridge, MA, USA.
Harvard Medical School, Boston, MA, USA.
Brain Struct Funct. 2022 Nov;227(8):2633-2645. doi: 10.1007/s00429-022-02560-4. Epub 2022 Sep 9.
The home language and literacy environment (HLLE) in infancy has been associated with subsequent pre-literacy skill development and HLLE at preschool-age has been shown to correlate with white matter organization in tracts that subserve pre-reading and reading skills. Furthermore, childhood socioeconomic status (SES) has been linked with both HLLE and white matter organization. It is important to understand whether the relationships between environmental factors such as HLLE and SES and white matter organization can be detected as early as infancy, as this period is characterized by rapid brain development that may make white matter pathways particularly susceptible to these early experiences. Here, we hypothesized that HLLE (1) relates to white matter organization in pre-reading and reading-related tracts in infants, and (2) mediates a link between SES and white matter organization. To test these hypotheses, infants (mean age: 8.6 ± 2.3 months, N = 38) underwent diffusion-weighted imaging MRI during natural sleep. Image processing was performed with an infant-specific pipeline and fractional anisotropy (FA) was estimated from the arcuate fasciculus (AF) and superior longitudinal fasciculus (SLF) bilaterally using the baby automated fiber quantification method. HLLE was measured with the Reading subscale of the StimQ (StimQ-Reading) and SES was measured with years of maternal education. Self-reported maternal reading ability was also quantified and applied to our statistical models as a proxy for confounding genetic effects. StimQ-Reading positively correlated with FA in left AF and to maternal education, but did not mediate the relationship between them. Taken together, these findings underscore the importance of considering HLLE from the start of life and may inform novel prevention and intervention strategies to support developing infants during a period of heightened brain plasticity.
婴儿期的家庭语言和读写环境（HLLE）与随后的读写前技能发展有关，并且学前 HLLE 与支持阅读前和阅读技能的白质组织相关。此外，儿童的社会经济地位（SES）与 HLLE 和白质组织都有关。了解环境因素（如 HLLE 和 SES）与白质组织之间的关系是否早在婴儿期就可以被检测到非常重要，因为这个时期的大脑发育迅速，这可能使白质通路特别容易受到这些早期经历的影响。在这里，我们假设 HLLE（1）与婴儿期阅读前和阅读相关的白质束的白质组织有关，（2）在 SES 和白质组织之间起到中介作用。为了检验这些假设，我们让婴儿（平均年龄：8.6±2.3 个月，N=38）在自然睡眠期间接受弥散加权成像 MRI。使用婴儿专用的管道进行图像处理，使用婴儿自动纤维定量法从双侧弓状束（AF）和上纵束（SLF）估计各向异性分数（FA）。使用 StimQ 的阅读子量表（StimQ-Reading）测量 HLLE，使用母亲受教育年限来测量 SES。我们还量化了母亲自述的阅读能力，并将其应用于我们的统计模型，以作为混杂遗传效应的代理。StimQ-Reading 与左侧 AF 的 FA 呈正相关，与母亲的教育程度呈正相关，但没有起到中介作用。综上所述，这些发现强调了从生命开始就考虑 HLLE 的重要性，并可能为支持大脑高度可塑性发育中的婴儿提供新的预防和干预策略。
