Learn More
Human mathematical competence emerges from two representational systems. Competence in some domains of mathematics, such as calculus, relies on symbolic representations that are unique to humans who have undergone explicit teaching. More basic numerical intuitions are supported by an evolutionarily ancient approximate number system that is shared by adults,(More)
Many children have significant mathematical learning disabilities (MLD, or dyscalculia) despite adequate schooling. The current study hypothesizes that MLD partly results from a deficiency in the Approximate Number System (ANS) that supports nonverbal numerical representations across species and throughout development. In this study of 71 ninth graders, it(More)
Researchers of mathematics learning disability (MLD) commonly use cutoff scores to determine which participants have MLD. Some researchers apply more restrictive cutoffs than others (e.g., performance below the 10th vs. below the 35th percentile). Different cutoffs may lead to groups of children that differ in their profile of math and related skills,(More)
We examined whether posterior vermis size is smaller in individuals with fragile X syndrome (fra X) than in control subjects and whether this decreased size is associated with cognitive performance. Cognitive and behavioral dysfunctions have been identified in fra X; however, underlying neuropathogenic mechanisms remain unclear. MRI was used to investigate(More)
This paper is a descriptive report of findings from a prospective longitudinal study of math disability (MD). The study was designed to address the incidence of MD during primary school, the utility of different MD definitions, and evidence of MD subtypes. The results illustrate the dynamic properties of psychometrically derived definitions of MD. Different(More)
The Approximate Number System (ANS) is a primitive mental system of nonverbal representations that supports an intuitive sense of number in human adults, children, infants, and other animal species. The numerical approximations produced by the ANS are characteristically imprecise and, in humans, this precision gradually improves from infancy to adulthood.(More)
The aim of the present study was to address how to effectively predict mathematics learning disability (MLD). Specifically, we addressed whether cognitive data obtained during kindergarten can effectively predict which children will have MLD in third grade, whether an abbreviated test battery could be as effective as a standard psychoeducational assessment(More)
The specificity of the neurocognitive profile among women with the fragile X gene, in relation to cytogenetic expression, was examined among 22 women with > or = 2% expression, 35 0% obligate carriers, and 60 controls. Measures were obtained for intellectual ability; achievement; and verbal, nonverbal, memory, and executive functions. Findings show that no(More)
Social skills impairment in children with Turner or fragile X syndrome has been documented using parental reports. Anxiety, shyness, and difficulty understanding social cues have been reported for females with Turner syndrome; whereas social withdrawal, avoidance of social interactions, and anxiety are often reported for females with fragile X syndrome.(More)
The present study examined whether indicators of math learning disability are observed in 5- and 6-year-olds with neurofibromatosis type 1 (NF1) and in 5- to 6-year-old girls with Turner syndrome or fragile X syndrome. Data from 14 girls with Turner syndrome, 9 girls with fragile X syndrome, and 11 children with NF1 were compared to data from control(More)