Effects of gestational age at birth on cognitive performance: a function of cognitive workload demands

Working memory in preterm-born adults: load-dependent compensatory activity of the posterior default mode network

Premature birth is associated with an increased risk of cognitive performance deficits that are dependent on working memory (WM) load in childhood. Less clear is whether preterm-born adults show similar WM impairments, or develop compensatory brain mechanisms that help to overcome prematurity-related functional deficits, for example, by a workload-dependent over-recruitment of WM-typical areas, and/or engagement of alternative brain networks. In this functional magnetic resonance imaging study, 73 adults born very preterm and/or with very low birth weight (VP/VLBW) and 73 term-born controls (CON, mean age: 26.5 years) performed a verbal N-Back paradigm with varying workload (0-back, 1-back, 2-back). Generally, both groups showed similar performance accuracy and task-typical patterns of brain activations (especially in fronto-cingulo-parietal, thalamic, and cerebellar areas) and deactivations (especially in mesial frontal and parietal aspects of the default mode network [DMN]). However, VP/VLBW adults showed significantly stronger deactivations (P < 0.05, cluster-level corrected) than CON in posterior DMN regions, including right ventral precuneus, and right parahippocampal areas (with adjacent cerebellar areas), which were specific for the most demanding 2-back condition. Consistent with a workload-dependent effect, VP/VLBW adults with stronger deactivations (1-back > 2-back) in the parahippocampal/cerebellar cluster also presented a greater slowing of response latencies with increasing WM load (2-back > 1-back), indicative of higher effort. In conclusion, VP/VLBW adults recruited similar anatomical networks as controls during N-back performance, but showed an enhanced suppression of posterior DMN regions during higher workload, which may reflect a temporary suppression of stimulus-independent thoughts that helps to maintain adequate task performance with increasing attentional demands.

Neurodevelopmental pathways to preterm children's specific and general mathematic abilities

BACKGROUND

Preterm children have problems with mathematics but knowledge about the predictors of specific mathematic abilities in preterm populations is scarce.

AIMS

This study investigated neurodevelopmental pathways to children's general and specific mathematic abilities across the full gestational age range.

STUDY DESIGN

Prospective geographically defined longitudinal investigation in Germany.

SUBJECTS

947 children across the full gestational age range (23-41 weeks). Outcome measures. At 8 years, children's cognitive and mathematic abilities were measured and residuals of a regression predicting mathematic scores by IQ were used to identify specific mathematic abilities.

RESULTS

Neurodevelopmental cascade models revealed that adverse effects of preterm birth on mathematic abilities were mediated by neonatal risk. Specific mathematic abilities were uniquely predicted by the duration of hospitalization and ventilation.

CONCLUSIONS

Prolonged neonatal medical treatment and, in particular, mechanical ventilation may lead to specific impairments in mathematic tasks. These findings have implications for the mode of respiratory support in neonates, routine follow-up and intervention planning as well as research about brain reorganization after preterm birth.

Preschool regulatory problems and attention-deficit/hyperactivity and cognitive deficits at school age in children born at risk: different phenotypes of dysregulation?

BACKGROUND

Early regulatory problems (RP), i.e., excessive crying, feeding, and sleeping difficulties, have been reported to be predictors of cognitive and attention-deficit/hyperactivity problems. However, previous studies had limitations such as small sample size or retrospective design.

AIM

To investigate whether persistent RP from infancy until preschool age are precursors of ADHD problems and cognitive deficits at school age.

STUDY DESIGN

A prospective study from birth to 8.5years of age.

SUBJECTS

1120 infants born at risk.

MEASURES

RP were assessed at 5months (i.e., excessive crying, feeding, and sleeping problems), 20, and 56months (i.e., eating and sleeping problems) via parent interviews and neurological examination. At 8.5years of age, IQ was assessed by a standard test (K-ABC), and ADHD problems by direct observations in the test situation and by the Mannheimer Parent Interview (MPI, DSM-IV diagnosis of ADHD).

RESULTS

23.8% of the sample born at risk had RP at least at two measurement points until preschool age. Persistent RP predicted lower IQ (β=-.17; 95% CI (-.21; -.10)), behaviour problems (β=-.10; 95% CI (-.15; -.03)), attention (OR 2.43; 95% CI (1.16; 5.09)) and hyperactivity problems (OR 3.10; 95% CI (1.29; 7.48)), and an ADHD diagnosis (OR 3.32; 95% CI (1.23; 8.98)) at school age, even when controlled for psychosocial and neurological confounders.

CONCLUSIONS

Early persistent RP increased the odds of ADHD and associated problems at school age, indicating a cascade model of development, i.e., infant behaviour problems provide the starting point of a trajectory of dysregulation through time.

A parent questionnaire for developmental screening in infants born late and moderately preterm

BACKGROUND

The Parent Report of Children's Abilities-Revised (PARCA-R) is a questionnaire for assessing cognitive and language development in very preterm infants. Given the increased risk of developmental delay in infants born late and moderately preterm (LMPT; 32-36 weeks), this study aimed to validate this questionnaire as a screening tool in this population.

METHODS

Parents of 219 children born LMPT completed the PARCA-R questionnaire and the Brief Infant Toddler Social and Emotional Assessment when children were 24 months corrected age (range, 24 months-27 months). The children were subsequently assessed by using the cognitive and language scales of the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III).

RESULTS

An average Bayley-III, cognitive and language (CB-III) score and a total PARCA-R Parent Report Composite (PRC) score were computed. There was a large association between PRC and CB-III scores (r = 0.66, P < .001) indicating good concurrent validity. Using Youden index, the optimum PARCA-R cutoff for identifying children with moderate/severe developmental delay (CB-III scores < 80) was PRC scores < 73. This gave sensitivity 0.90 (95% confidence interval: 0.75-1.00) and specificity 0.76 (95% confidence interval: 0.70-0.82), indicating good diagnostic utility. Approximately two-thirds of the children who had a PRC score < 73 had false-positive screens. However, these children had significantly poorer cognitive and behavioral outcomes than children with true negative screens.

CONCLUSIONS

The PARCA-R has good concurrent validity with a gold standard developmental test and can be used to identify LMPT infants who may benefit from a clinical assessment. The PARCA-R has potential for clinical use as a first-line cognitive screening tool for this sizeable population of infants in whom follow-up may be beneficial.

Preterm birth and dyscalculia

OBJECTIVE

To evaluate whether the risk for dyscalculia in preterm children increases the lower the gestational age (GA) and whether small-for-gestational age birth is associated with dyscalculia.

STUDY DESIGN

A total of 922 children ranging from 23 to 41 weeks' GA were studied as part of a prospective geographically defined longitudinal investigation of neonatal at-risk children in South Germany. At 8 years of age, children's cognitive and mathematic abilities were measured with the Kaufman Assessment Battery for Children and with a standardized mathematics test. Dyscalculia diagnoses were evaluated with discrepancy-based residuals of a linear regression predicting children's math scores by IQ and with fixed cut-off scores. We investigated each GA group's ORs for general cognitive impairment, general mathematic impairment, and dyscalculia by using binary logistic regressions.

RESULTS

The risk for general cognitive and mathematic impairment increased with lower GA. In contrast, preterm children were not at increased risk of dyscalculia after statistically adjusting for child sex, family socioeconomic status, and small-for-gestational age birth.

CONCLUSION

The risk of general cognitive and mathematic impairments increases with lower GA but preterm children are not at increased risk of dyscalculia.

Effects of sensitive parenting on the academic resilience of very preterm and very low birth weight adolescents

PURPOSE

Although sensitive and cognitively stimulating parenting is a powerful predictor of school success, it may not protect against increased neonatal risk resulting from underlying neurological damage.

METHODS

A total of 314 very preterm/very low birth weight (VP/VLBW) and 338 term control children were studied from birth to age 13 years. Socioeconomic status was examined at birth. Neurological and physical impairment was assessed at age 20 months, and sensitive and cognitively stimulating parenting at age 6 years. School success was measured from 6 to 13 years of age.

RESULTS

Very preterm/very low birth weight children had lower school success between 6 and 13 years, after statistically controlling for child disability and socioeconomic status. Cognitively stimulating parenting promoted all children's school success whereas highly sensitive parenting at age 6 years partly protected against the adverse effects of VP/VLBW birth on academic outcomes.

CONCLUSIONS

Very preterm/very low birth weight children's school success to age 13 years may be partly protected with sensitive parenting in middle childhood, despite the neurodevelopmental impairments associated with VP/VLBW birth. This suggests potential avenues for interventions for children born at high neonatal risk.