Preterm children do not have an increased risk for dyscalculia, new research suggests

Thanks to modern medicine, the percentage of preterm survivors is constantly increasing. On the cognitive level, these children frequently have long-term problems such as poor arithmetic skills and difficulty concentrating. For a long time, research focused on high-risk children, born before 32 weeks gestational age or with less than 1,500 gram. Current studies from the most recent years, however, show that this approach is too short-sighted.

Dr Julia Jäkel from the Department of Developmental Psychology has analysed cognitive abilities of children born between 23 and 41 weeks gestation. In doing so, she covered the entire spectrum, ranging from extremely preterm to healthy term born infants. For this purpose, she used data of the Bavarian Longitudinal Study, which has been following a birth cohort from the late 80s until today. "Having access to such a comprehensive long-term study is a dream come true for every developmental psychologist," says the Bochum researcher. Over the course of the study, all children underwent a whole battery of tests that assessed their cognitive and educational abilities, and their parents were interviewed in depth.

The RUB researcher has so far mainly focused on data collected at preschool and early school age. For different test tasks, she assessed their cognitive workload, a criterion for the complexity of a given task. The data showed that preterm children had greater difficulties with tasks that demanded higher working memory resources. Moreover, results revealed that not only high-risk children had significant difficulties. On average, the more preterm a child had been born, the poorer were his or her abilities to solve complex tasks.

But what exactly is the nature of these difficulties? It has been frequently suggested that preterm children suffer from dyscalculia. A phenomenon that Julia Jäkel examined more closely. "Mathematical deficiencies, maths learning disorder, dyscalculia, innumeracy -- these terms' definitions vary slightly," she explains, but there are no standardised, internationally consistent diagnostic criteria. In order to assess specific maths deficiencies, children in Germany are assessed with a number of tests. If their results fall below a certain cut off value in maths while their cognitive skills (IQ) are in the normal range, they are diagnosed with "maths learning disorder" or "dyscalculia."

"The problem with preterm children, however, is that they often have general cognitive deficits," Julia Jäkel points out. "According to current criteria, these children can't be diagnosed." Together with Dieter Wolke from the University of Warwick, UK, she compared different diagnostic criteria for dyscalculia in her analysis. The aim of the study was to identify specific maths deficiencies in preterm children that were independent of general cognitive impairments. With surprising results: "There is no specific maths deficit in preterm children if their general IQ is factored in," says the researcher.

This means that preterm children do not suffer from dyscalculia more often than term children. However, they often have maths difficulties and these may not be recognized. This is because the current criteria make it impossible to diagnose dyscalculia if a child also has general cognitive deficits. Thus, these children do not receive specific help in maths although they may be in urgent need. "We need reliable and consistent diagnostic criteria," demands Julia Jäkel. "And we've got to find ways to actually deliver support in schools."

Together with her British team, the psychologist compared the results of the Bavarian Longitudinal Study with "EPICure" data, a similar study that commenced in the UK in the 1990s, following a cohort of extremely preterm children. The researchers focus on mathematical and educational performance. British preterm children had similar cognitive and basic numerical skills as German preterm children. In terms of maths achievement, however, they showed significantly better results. "We explain this with the fact that, unlike in Germany, in the UK it has not been possible for children to delay school entry," explains Julia Jäkel. "In addition, special schools are attended by only a small percentage of extremely disabled children. All other children are integrated into normal classes in regular schools and receive targeted support there."

The developmental psychologist has already demonstrated that assistance at primary-school age can really make a difference. Parents who support their preterm children with sensitive scaffolding can compensate the negative cognitive effects of preterm birth. It is helpful, for example, if parents give their children appropriate feedback to homework tasks and suggest potential solutions, rather than solving the tasks for the child. However, Julia Jäkel believes that a lot of research is yet to be done as far as intervention is concerned: "A large percentage of parents is very dedicated and has resources to help their children," she says. "But research has not yet produced anything that would ensure successful results in the long-term." Together with colleagues from the university hospital in Essen, the RUB researcher plans to investigate the benefits of computer-aided working memory training for preterm children's school success, which has already been successfully applied on an international level.

It would also be helpful if findings from related disciplines, such as developmental psychology, educational research, and neonatal medicine were better integrated. This is, for example, because neonatal medical treatment can significantly affect later cognitive performance. Together with her interdisciplinary team, Julia Jäkel used a comprehensive model to analyse to what extent different neonatal medical indicators affect cognitive development at age 20 months, attention abilities at age six, and maths abilities at age eight years. In her analyses, she factored in child sex and socio-economic status.

Results showed that neonatal medical variables, e.g., the duration of mechanical ventilation, predicted cognitive abilities at age 20 months. Both factors together predicted attention regulation at age six years. And all those precursors, in turn, affected long-term general maths abilities.

Subsequently, Julia Jäkel analysed the data once again from a different perspective, in order to predict specific maths skills that were independent of the child's IQ. In that model, only two variables had direct impact: the duration of mechanical ventilation and hospitalisation after birth. In the 1980s, when children participating in the Bavarian Longitudinal Study were born, German doctors often used invasive ventilation methods. Today, less invasive methods are available, but to what extent they may affect long-term cognitive performance has not yet been investigated.

"Both too high and too low oxygen concentrations are harmful to brain development," explains Julia Jäkel. "The neonatologist in charge is faced with the great challenge of determining the right dose for each infant, depending on individually changing situations." This is why it is so important to integrate psychological models with neonatal intensive care research. The joint objective is to offer preterm children the chance of a successful school career, high quality of life and social participation.