Being born preterm goes hand in hand with an increased risk for neuro-cognitive deficits. Psychologists from the Ruhr-Universität Bochum and the University of Warwick, UK have investigated the relation between the duration of pregnancy and cognitive abilities under varying work load conditions. "Cognitive performance deficits of children dramatically increase as cognitive workload of tasks increases and pregnancy duration decreases," says Dr Julia Jäkel from the Ruhr-Universität. In the journal "PLOS ONE", the researchers report a new cognitive workload model describing the association between task complexity and incremental performance deficits of preterm children.

 

 

About 15 million, i.e., more than ten per cent of all babies worldwide are born preterm every year; that is before the 37th week of pregnancy – and the numbers are rising due to improvements in neonatal medicine and demographic changes. Recent studies suggest that delivery at any gestation other than full term (39 to 41 weeks gestational age) may impair brain development, rendering survivors at risk for adverse neuro-cognitive outcomes. Considering that 50 per cent of children are born before the 39th week of pregnancy, even small increases in cognitive impairments may have large effects on a population level. "As the total number of children born preterm increases there will be parallel increases in special education needs placing new demands on the education system," Julia Jäkel and her colleagues say. To date, uncertainties remain regarding the nature and underlying causes of learning difficulties in preterm children. The new cognitive workload model now reconciles previous inconsistent findings on the relationship of gestational age and cognitive performance.

The research team tested 1326 children, born between weeks 23 and 41 of pregnancy, at an age of eight years. Data were collected as part of the prospective Bavarian Longitudinal Study. The children took part in a range of cognitive tests with varying workload. High workload tasks require the simultaneous integration of different sources of information, thereby placing high demands on the so called working memory. The results: The higher the workload and the shorter the pregnancy duration, the larger were the cognitive performance deficits. Deficits were disproportionally higher for children born before the 34th week of pregnancy compared with children born after week 33. Being born preterm specifically affected the ability to solve high workload tasks, whereas lower workload tasks were largely unaffected.

According to the researchers, these results should be taken into account for routine cognitive follow-ups of preterm children as well as for planning school lessons. "New studies suggest that computerized training can improve working memory capacity," Prof Dieter Wolke from Warwick says. "In addition, educational interventions could be developed in which information is not presented simultaneously to preterm children but more slowly and sequentially to promote academic attainment."

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Julia Jaekel, PhD, Dieter Wolke, PhDemail address

Received 31 July 2013; received in revised form 3 December 2013; accepted 31 January 2014. published online 14 March 2014. 

 

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.

 

 

 

 

Researchers have found that preterm children are at an increased risk of having general cognitive and mathematic problems.

 

The new study by the University of Warwick and Ruhr-University Bochum, published in the Journal of Pediatrics, sought to understand the relationship between preterm birth and dyscalculia.

Dyscalculia, a learning disorder which involves frequent problems with everyday arithmetic tasks, is diagnosed when children do worse in maths than would be expected based on their general intelligence.

Study co-author Professor Dieter Wolke from the University of Warwick explained, "Mathematic impairment is not the same as dyscalculia. A child with both low IQ and low mathematic abilities can have general mathematic impairment without suffering from dyscalculia".

The study's results, which looked at 922 children between the ages of seven and nine, showed that there is no direct correlation between preterm births and dyscalculia. However, the authors showed that being small-for-gestational-age is an indicator of whether a child is likely to have dyscalculia.

Children who are born very preterm, before 32 weeks, of gestational age have a 39.4% chance of having general mathematic impairment compared to 14.9% of those born at term (39 to 41 weeks), which translates into a significantly increased odds ratio of 3.22 (after controlling for child sex, socioeconomic background and small-for-gestational-age birth).

In contrast, very preterm children's risk of being diagnosed with dyscalculia was with an odds ratio of 1.62 (22.6%) compared with term controls (13.7%) not significantly increased.

"What this study has shown is that preterm children are not at an increased risk of having dyscalculia, but their risk may be increased if they were born small for gestational age", says Professor Wolke.

Dr Julia Jaekel from the Ruhr-University Bochum, co-author of the study, points out that "In general, preterm and small-for-gestational-age children often have mathematic problems and, even if they are not diagnosed with dyscalculia, they may need special help in school to not be left behind academically.

Through the right support teachers and parents can help their children understand the problem and learn ways to improve their maths skills. Just as dyslexia doesn't mean that children won't be able to read and write to a high standard, being diagnosed with dyscalculia may not stop a child from gaining a strong understanding of mathematics.

"Teachers should be aware of these children's problems and need to work on ways of math instruction that help preterm children deal with the high cognitive workload and integration of information required for mathematic tasks in school", says Prof Wolke.

 

 

 

 

 

 

 

HomePediatricsApril 30, 2013

Fredrik Serenius, M.D., Ph.D., of Uppsala University, Uppsala, Sweden, and colleagues conducted a study to assess neurological and developmental outcome in extremely preterm (less than 27 gestational weeks) children at 2.5 years.

 

 

"A proactive approach to resuscitation and intensive care of extremely preterm infants has increased survival and lowered the gestational age of viability. There are concerns that increased survival may come at the cost of later neurodevelopmental disability among survivors. Approximately 25 percent of extremely preterm infants born in the 1990s had a major disability at preschool age, such as impaired mental development, cerebral palsy, blindness, or deafness. More recent studies report decreasing, unchanged, or increasing rates of neurodevelopmental disability at preschool age compared with previous decades," according to background information in the article.

The study included extremely preterm infants born in Sweden between 2004 and 2007. Of 707 live-born infants, 491 (69 percent) survived to 2.5 years. Survivors were assessed and compared with control infants who were born at term and matched by sex, ethnicity, and municipality. Assessments ended in February 2010 and comparison estimates were adjusted for demographic differences. Cognitive, language, and motor development were assessed. Clinical examination and parental questionnaires were used for diagnosis of cerebral palsy and visual and hearing impairments. Assessments were made by week of gestational age.

At a median (midpoint) age of 30.5 months, 456 of 491 (94 percent) extremely preterm children were evaluated (41 by chart review only). The researchers found that overall, 42 percent of extremely preterm children had no disability (compared with 78 percent of control participants), 31 percent had mild disability, 16 percent had moderate disability, and 11 percent had severe disability. There was an increase in moderate or severe disabilities with decreasing gestational age. Also, the difference in overall outcome between preterm boys and girls was not statistically significant.

"Improved survival did not translate into increasing disability rates, and we like others believe that the neurodevelopmental outcome for extremely preterm children born in the 2000s will be better than for those born in the 1990s. Nevertheless, the impact of prematurity on neurodevelopmental outcome was large, which calls for further improvements in neonatal care, such as better control of infection and postnatal nutrition," the authors write.

"These results are relevant for clinicians counseling families facing extremely preterm birth."

More information: JAMA. 2013;309[17]:1810-1820