Number estimation in Down syndrome: Cognition or experience?

Background: The ability to place numbers on a visual “number line” is a hallmark of the understanding of numerical magnitude and it is a strong predictor of mathematical achievement. Aim: We examined whether the performance in the number line estimation task is more driven by mental age or experience with numbers in a sample of Italian children with Down syndrome (DS). Method and procedure: Sixty-three children with DS (Mmonths = 128.62, SD = 30.73) and sixty-three typically developing children (Mmonths = 54.98, SD = 6.34) matched one to one for mental age completed number line estimation tasks and other tests to assess their numerical knowledge. Outcomes and results: No significant differences emerged between the two groups in terms of accuracy of positioning numbers on the 1–10 and 1–20 interval. In addition, the accuracy on the 1–10 interval was related to the ability to recognize numbers, while the accuracy on the 1–20 line was related to the ability to compare magnitudes. Conclusion and Implication: Results suggest that in individuals with DS the linear mapping of numbers is driven by mental age, but the accuracy of positioning numbers is also shaped by the experience with symbolic numbers. Therefore, the improvement of numerical estimation abilities should be a target of intervention programs.</p

Parent-based training of basic number skills in children with Down syndrome using an adaptive computer game

Background Numeracy is an area of difficulty for children with Down Syndrome (DS). It has been demonstrated that “The Number Race”, a non-commercial adaptive computer game designed to foster basic mathematical abilities, represents a promising instrument to enhance these skills in children with DS when delivered by an expert in a clinical setting. Aims In the present study, we assessed the efficacy of the Number Race when administered at home by properly instructed and remotely supervised parents. Methods and Procedures Basic numerical skills were assessed before and after training, as well as at three-months follow-up. Performance of children with DS who worked at home with the parent (PG) was compared with that of children who received the training by an expert (EG). For both groups, the training lasted ten weeks, with two weekly sessions of 20-30 minutes. Outcomes and Results Results show that both groups improved across various measures of numerical proficiency, including the overall score of the numeracy assessment battery, while only the EG showed an improvement in a measure of mental calculation. The improvements were maintained three months after the end of the training. Conclusions and Implications These findings confirm the efficacy of The Number Race and extend it to a home-based setting, whereby parents administer the training with external supervision

Training basic numerical skills in children with Down syndrome using the computerized game “The Number Race”

Individuals with Down syndrome (DS) present reduced basic numerical skills, which have a negative impact on everyday numeracy and mathematical learning. Here, we evaluated the efficacy of the adaptive (non-commercial) computerized game “The Number Race” in improving basic numerical skills in children with DS. The experimental group (EG; Mage-in-months=118, range=70-149) completed a training playing with “The Number Race”, whereas children in the control group (CG; Mage-in-months=138, range=76-207) worked with software aiming at improving their reading skills. The training lasted 10 weeks with two weekly sessions of 20-30 minutes each. We assessed both groups’ numerical and reading skills before and immediately after the end of the training, as well as at a 3-months followup. We found weak evidence for post-training groups differences in terms of overall numeracy score. However, the EG displayed substantial improvements in specific numerical skills and in mental calculation, which were maintained over time, and no improvement in reading. Conversely, the CG showed improvements in their reading skills as well as in number skills but to a lesser extent compared to the EG. Overall, “The Number Race” appears as a suitable tool to improve some aspects of numeracy in DS

Severe developmental dyscalculia is characterized by core deficits in both symbolic and nonsymbolic number sense

A long-standing debate concerns whether developmental dyscalculia is characterized by core deficits in processing nonsymbolic or symbolic numerical information as well as the role of domain-general difficulties. Heterogeneity in recruitment and diagnostic criteria make it difficult to disentangle this issue. Here, we selected children ( n = 58) with severely compromised mathematical skills (2 SD below average) but average domain-general skills from a large sample referred for clinical assessment of learning disabilities. From the same sample, we selected a control group of children ( n = 42) matched for IQ, age, and visuospatial memory but with average mathematical skills. Children with dyscalculia showed deficits in both symbolic and nonsymbolic number sense assessed with simple computerized tasks. Performance in the digit-comparison task and the numerosity match-to-sample task reliably separated children with developmental dyscalculia from controls in cross-validated logistic regression (area under the curve = .84). These results support a number-sense-deficit theory and highlight basic numerical abilities that could be targeted for early identification of at-risk children as well as for intervention

Low discriminative power of WISC cognitive profile in developmental dyscalculia

Background: The role of domain-general cognitive abilities in the etiology of Developmental Dyscalculia (DD) is a hotly debated issue. Aims: In the present study, we tested whether WISC-IV cognitive profiles can be useful to single out DD. Methods and procedures: Using a stringent 2-SD cutoff in a standardized numeracy battery, we identified children with DD (N = 43) within a clinical sample referred for assessment of learning disability and compared them in terms of WISC cognitive indexes to the remaining children without DD (N = 100) employing cross-validated logistic regression. Outcomes and results: Both groups showed higher Verbal Comprehension and Perceptual Reasoning than Working Memory and Processing Speed, and DD scores were generally lower. Predictive accuracy of WISC indexes in identifying DD individuals was low (AUC = 0.67) and it dropped to chance level in discriminating DD from selected controls (N = 43) with average math performance but matched on global IQ. The inclusion of a visuospatial memory score as an additional predictor did not improve classification accuracy. Conclusions and implications: These results demonstrate that cognitive profiles do not reliably discriminate DD from non-DD children, thereby weakening the appeal of domain-general accounts.</p