Deficits in numerical magnitude perception characterize the mathematics learning disability developmental dyscalculia (DD), but recent studies suggest the relation stems from inhibitory control demands from incongruent visual cues in the nonsymbolic number comparison task. This study investigated the relation among magnitude perception during…

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…

Results obtained from 44 children (ages 7 through 16) with sex chromosome abnormalities and from 17 chromosomally normal siblings demonstrated that children in the former group have an increased risk of encountering learning problems. (MP)

Comprehensively reviews known examples of genetically influenced learning disabilities and speech and language disorders, including familial dyslexia, stuttering, and other speech and language disorders, as well as sex-chromosome anomalies, treated PKU, and minor auto-somal anomalies. (Author/RH)

The apprehension spans of learning-disabled and normal boys were compared by means of a forced-choice letter-recognition task involving tachistoscopic exposures of letter displays. Results of three experiments indicated that the decreased spans of apprehension observed in the first experiment for learning-disabled boys resulted either from greater…

Using strict and lenient mathematics achievement cutoff scores to define a learning disability, respective groups of children who are math disabled (MLD, n = 15) and low achieving (LA, n = 44) were identified. These groups and a group of typically achieving (TA, n = 46) children were administered a battery of mathematical cognition, working…

Compares the development of working memory in normally achieving children and learning disabled children. Results show a growth of working memory as a function of age. Deficits in working memory for subtypes of learning disabled children are discussed. (RJC)

Examined children's mathematical competencies between ages 7 and 9. Found no differences in developmental rate between children with math difficulties only (MD), math and reading difficulties (MD-RD), reading difficulties only (RD), and normal math/reading achievement (NA). Found that at end of Grade 3, MD group performed better than MD-RD group…

Compared the processing of rapid auditory stimuli on two-tone auditory discrimination tasks by 7- to 11-year-olds with learning impairments (LI) and those without learning impairments (non-LI). Found that LI children committed more errors, but the effects of timing were comparable. Obtained same results with a sample of good and poor readers. Task…