Page 69 - Sample Moderate prematurity, socioeconomic status, and neurodevelopment in early childhood

particular regarding executive functioning.34 In summary, low SES is an important risk factor for delay in problem-solving skills, also in MP children.
We found intriguing, mixed effects of low SES and moderate prematurity on communication skills, implying that SES had less influence on these skills in MP children (Chapter 2). Across all SES levels, 8% to 10% of MP children had delay in communication skills, contrary to full-term children, in whom these rates increased markedly with decreasing SES (from 2% to 13%), as expected. One explanation for this finding may be that MP children with low SES had received more special care than full-term children with low SES, which may have diminished the adverse effects of low SES. This explanation is, however, refuted by the fact that MP children were generally not recognized as at risk of developmental delay before the LOLLIPOP study commenced.35
Behavioural and emotional problems in MP children with developmental delay
In comparison to full-term children, we found that MP children had higher rates of behavioural and emotional problems at pre-school age, which is consistent with findings from other studies.36 Most children, however, will not develop these problems at an early age,37 but some children are at high risk of developing such problems later on. Co-occurrence of developmental and behavioural problems is one of the predictors of persistent problems. Of the MP children with developmental delay, up to a third had some form of co-occurring developmental and behavioural problems, which is considerable. To the best of our knowledge, no prior studies on co-occurrence have been done on MP children, although it has been suggested previously that in these children motor coordination problems, such as clumsy, uncoordinated movements, occurred frequently in combination with inattention, hyperactivity, and impulsivity.38
A number of neurophysiologic and psychosocial hypotheses have been
proposed to explain why developmental and behavioural problems frequently co- 7 occur.39, 40 These hypotheses are partly in line with the main pathways that we
proposed in order to explain higher rates of neurodevelopmental problems in MP
and low SES children, i.e. the degree of parental well-being and involvement in the
pre-school years, and the disruptive effects of moderate prematurity and low SES
on brain development. Below, we briefly discuss two hypotheses that have been
proposed in prior studies, and which may offer explanations for the emergence of
co-occurring problems.
General discussion
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