Basic numerical processes in very preterm children: A critical transition from preschool to school age

Background: Serious difficulties in formal mathematical skills have been identified in preterm children. By contrast, basic-level numerical skills like magnitude judgments have not yet been tested in these children. Aims: The aimof the present research was to investigate whether pretermbirth also affects these basic numerical abilities, with particular attention to the transition from preschool to formal education. Method: One hundred-forty very preterm children and 60 age-matched controls were recruited in a crosssectional study at 6 and 8 years of age. Magnitude comparison tasks with non-symbolic dot displays or symbolic Arabic-number stimuli,measuring accuracy and reaction time, were administered to participants.We also investigated explicit number knowledge, aswell as general cognitive developmental levels, to gain a broader picture of preterm abilities. Results: Despite no general cognitive delay, the more simple approximate non-symbolic representation of numericalmagnitude was affected by pretermbirth,with slower reaction times at both ages compared to controls. Additionally, clear difficulties in the construction of the symbolic representation of numerical magnitude and in explicit number knowledge emerged in the 6-year-old pretermchildren, with a recovery from this serious delay finally by 8 years. Conclusions: The serious delays identified here in basic numerical abilities in pretermchildren, despite normal IQ, point to the need for further studies in order to elucidate the relationship between basic numerical abilities and subsequent difficulties in formal mathematic achievement at school.