Given the well-documented failings in mathematics education in many Western societies, there has been an increased interest in understanding the cognitive underpinnings of mathematical achievement. Recent research has proposed the existence of an Approximate Number System (ANS) which allows individuals to represent and manipulate non-verbal numerical information. Evidence has shown that performance on a measure of the ANS (a dot comparison task) is related to mathematics achievement, which has led researchers to suggest that the ANS plays a critical role in mathematics learning. Here we show that, rather than being driven by the nature of underlying numerical representations, this relationship may in fact be an artefact of the inhibitory control demands of some trials of the dot comparison task. This suggests that recent work basing mathematics assessments and interventions around dot comparison tasks may be inappropriate.

Epidemiologic studies have, for many years, identified preterm birth as a significant risk factor for psychiatric disorders. There has been a recent resurgence of interest in neurobehavioral outcomes after preterm birth. In this article, we review clinical cohort studies of the prevalence, etiology, and risk factors for psychiatric sequelae in ex-preterm children. Studies using diagnostic psychiatric evaluations are few in number but typically report a 3- to 4-fold increased risk for disorders in middle childhood. Our review of studies reveals a "preterm behavioral phenotype" characterized by an increased risk for symptoms and disorders associated with inattention, anxiety, and social difficulties. The most contemporary studies have also reported a markedly increased prevalence of autism spectrum disorders (ASD) in preterm populations. Our examination of the correlates and comorbidities of psychiatric disorders is indicative of a different causative pathway that may be associated with altered brain development after preterm birth. Despite the low population attributable risk, the frequency of these symptoms and disorders means that psychiatric screening is likely to be beneficial in this vulnerable population.

Objective To determine outcomes at age 3 years in babies born before 27 completed weeks' gestation in 2006, and to evaluate changes in outcome since 1995 for babies born between 22 and 25 weeks' gestation.Design Prospective national cohort studies, EPICure and EPICure 2. Setting Hospital and home based evaluations, England.Participants 1031 surviving babies born in 2006 before 27 completed weeks' gestation. Outcomes for 584 babies born at 22-25 weeks' gestation were compared with those of 260 surviving babies of the same gestational age born in 1995.Main outcome measures Survival to age 3 years, impairment (2008 consensus definitions), and developmental scores. Multiple imputation was used to account for the high proportion of missing data in the 2006 cohort. ResultsOf the 576 babies evaluated after birth in 2006, 13.4% (n=77) were categorised as having severe impairment and 11.8% (n=68) moderate impairment. The prevalence of neurodevelopmental impairment was significantly associated with length of gestation, with greater impairment as gestational age decreased: 45% at 22-23 weeks, 30% at 24 weeks, 25% at 25 weeks, and 20% at 26 weeks (P<0.001). Cerebral palsy was present in 83 (14%) survivors. Mean developmental quotients were lower than those of the general population (normal values 100 (SD 15)) and showed a direct relation with gestational age: 80 (SD 21) at 22-23 weeks, 87 (19) at 24 weeks, 88 (19) at 25 weeks, and 91 (18) at 26 weeks. These results did not differ significantly after imputation. Comparing imputed outcomes between the 2006 and 1995 cohorts, the proportion of survivors born between 22 and 25 weeks' gestation with severe disability, using 1995 definitions, was 18% (95% confidence interval 14% to 24%) in 1995 and 19% (14% to 23%) in 2006. Fewer survivors had shunted hydrocephalus or seizures. Survival of babies admitted for neonatal care increased from 39% (35% to 43%) in 1995 to 52% (49% to 55%) in 2006, an increase of 13% (8% to 18%), and survival without disability increased from 23% (20% to 26%) in 1995 to 34% (31% to 37%) in 2006, an increase of 11% (6% to 16%). ConclusionSurvival and impairment in early childhood are both closely related to gestational age for babies born at less than 27 weeks' gestation. Using multiple imputation to account for the high proportion of missing values, a higher proportion of babies admitted for neonatal care now survive without disability, particularly those born at gestational ages 24 and 25 weeks. IntroductionThe survival of babies born at extremely low gestational ages increased in England between 1995 and 2006 but there were few improvements in neonatal morbidity. 1 Indeed, higher survival rates were reported in the Swedish population study, EXPRESS (Extremely Preterm Infants in Sweden Study), 2 yet the proportions of survivors without major neonatal morbidity was similar to those in this, the EPICure 2 study, and described in the accompanying paper.1 This is despite the widespread introduction of interventions to improve outcomes such as the ...

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Objectives To investigate the prevalence, correlates, and antecedents of autism spectrum disorders (ASD) in extremely preterm children. Study designWe conducted a prospective study of all births <26 weeks gestation in the United Kingdom and Ireland in 1995. Of 307 survivors at 11 years, 219 (71%) were assessed and compared with 153 term-born classmates. Parents completed the Social Communication Questionnaire (SCQ) to assess autism spectrum symptoms, and ASD were diagnosed by using a psychiatric evaluation. An IQ test and clinical evaluation were also administered. Longitudinal outcome data were available for extremely preterm children.Results Extremely preterm children had significantly higher SCQ scores than classmates (mean difference, 4.6 points; 95% CI, 3.4-5.8). Sixteen extremely preterm children (8%) were assigned an ASD diagnosis, compared with none of the classmates. By hospital discharge, male sex, lower gestation, vaginal breech delivery, abnormal cerebral ultrasound scanning results, and not having had breast milk were independently associated with autism spectrum symptoms. By 6 years, independent associates were cognitive impairment, inattention and peer problems, withdrawn behavior at 2.5 years, and not having had breast milk.Conclusions Extremely preterm children are at increased risk for autism spectrum symptoms and ASD in middle childhood. These symptoms and disorders were associated with neurocognitive outcomes, suggesting that ASD may result from abnormal brain development in this population. (J Pediatr 2010;156:525-31).

Extremely preterm children remain at high risk for neurodevelopmental disability at 11 years of age compared with term peers. The prevalence of disability remained stable between 6 and 11 years of age, and large individual shifts in classification of disability were unusual.

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