Page 68 - Sample Moderate prematurity, socioeconomic status, and neurodevelopment in early childhood

Chapter 7
microstructural and neural connectivity processes have been found in the brains of preterm children.19 Given their developmental stage at birth, particularly MP and late preterm children particularly lack part of the intrauterine development of the limbic system and cerebellum, in which structural changes take place after 32 weeks of gestation. Therefore, lacking the last stage of intrauterine brain growth may later become manifest as difficulties in controlling complex motor or mental tasks.20-22 Corresponding with this biological explanation, impairments of MP children mainly include fine motor skills, handwriting, coordination, and verbal fluency,23-26 contrary to the much broader array of developmental problems, including gross motor problems, in very preterm children.
Findings from the field of neuroscience indicate that low SES affects brain development, in particular involving those brain structures that are relevant for language processing.15 Our study supports this notion, since low SES affected communication skills, including language comprehension, more so than other developmental domains. We found that 12.5% of full-term children with low SES had delay in communication skills compared to 2% of full-term children with high SES (Chapter 2). Importantly, the adverse effects of low SES in childhood do not stand on their own: prenatal factors, parent-child interactions, cognitive stimulation, and stress are all candidate mediators for the effects of low SES on brain development.15, 27, 28 For example, stress may mediate effects of low SES because it has been related directly to the altered functioning of several brain areas and regulation systems, including the limbic system, the cerebellum, and the hypothalamic-pituitary-adrenal axis.27-29
Influence of SES on specific developmental domains
Low family SES had a greater influence on certain cognitive skills than on other developmental domains. First, problem solving skills in MP and full-term children were largely explained by SES, which confirms findings from prior studies. In preterm children born after 30 weeks of gestation, low parental educational level largely explained poorer cognitive outcomes, instead of preterm birth itself.30, 31 Other researchers have estimated that the intelligence quotient decreases with two points per week of decrease in gestational age,32 but it is unclear whether this translates directly into delayed cognitive development and eventually lower educational attainment. The latter seems to depend on genetic and socioeconomic determinants rather than on the gestational age of the child,33 pointing at the prominent role of low family SES in long-term neurocognitive performance, in
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