Word Generation scores separated by group.

It has been widely assessed that very preterm children (<32 weeks gestational age) present language and memory impairments compared with full-term children. However, differences in their underlying semantic memory structure have not been studied yet. Nevertheless, the way concepts are learned and organized across development relates to children’s capacities in retrieving and using information later. Therefore, the semantic memory organization could underlie several cognitive deficits existing in very preterm children. Computational mathematical models offer the possibility to characterize semantic networks through three coefficients calculated on spoken language: average shortest path length (i.e., distance between concepts), clustering (i.e., local interconnectivity), and modularity (i.e., compartmentalization into small sub-networks). Here we assessed these coefficients in 38 very preterm schoolchildren (aged 8–10 years) compared with 38 full-term schoolchildren (aged 7–10 years) based on a verbal fluency task. Using semantic network analysis, very preterm children showed a longer distance between concepts and a lower interconnectivity at a local level than full-term children. In addition, we found a trend for a higher modularity at a global in very preterm children compared with full-term children. These findings provide preliminary evidence that very preterm children demonstrate subtle impairments in the organization of their semantic network, encouraging the adaptation of the support and education they receive.

已有大量研究证实，相较于足月儿，极早产儿（胎龄<32周）会表现出语言与记忆功能损伤。然而，目前学界尚未针对其潜在的语义记忆（semantic memory）结构差异展开相关研究。尽管如此，个体在发育过程中概念的习得与组织方式，会对其后续提取与运用信息的能力产生影响。因此，极早产儿的语义记忆组织方式，或许是其出现多项认知缺陷的潜在诱因。计算数学模型可通过基于口语语料计算得到的三项系数，对语义网络（semantic network）进行特征刻画：平均最短路径长度（average shortest path length，即概念间的距离）、聚类系数（clustering，即局部互联程度）以及模块化系数（modularity，即划分为小子网络的特性）。本研究基于言语流畅性任务（verbal fluency task），对38名8~10岁极早产学龄儿童与38名7~10岁足月儿学龄儿童的上述三项系数进行了测算对比。通过语义网络分析，研究团队发现极早产儿童的概念间距离更长，且局部互联程度低于足月儿。此外，研究还观察到，极早产儿童的全局模块化程度存在高于足月儿的趋势。本研究结果初步证实，极早产儿的语义网络组织存在细微损伤，这一发现可为相关支持与教育方案的优化提供参考依据。