Developmental dyscalculia (DD) is a specific learning disability in mathematics that affects around 6% of the population. Currently, the core deficit of DD remains unknown. While the number sense deficit hypothesis suggests that the core deficit of DD lies in the inability to represent nonsymbolic numerosity, the access deficit hypothesis suggests…

The current study tested a multiple-cognitive predictor model of word reading, math ability, and attention in a community-based sample of twins ages 8 to 16 years (N = 636). The objective was to identify cognitive predictors unique to each skill domain as well as cognitive predictors shared among skills that could help explain their overlap and…

This study investigated if developmental dyscalculia (DD) in children with different profiles of mathematical deficits has the same or different cognitive origins. The defective approximate number system hypothesis and the access deficit hypothesis were tested using two different groups of children with DD (11-13 years old): a group with…

In transparent orthographies like German, isolated learning disabilities in either reading or spelling are common and occur as often as a combined reading and spelling disability. However, most issues surrounding the cognitive causes of these isolated or combined literacy difficulties are yet unresolved. Recently, working memory dysfunctions have…

There is a plethora of research suggesting that daily stressors and fatigue can have a significant effect on learning and various cognitive functions in young adults. Little is known, however, about how these effects impact learning and other neurocognitive functions in students with learning challenges when compared to their counterparts without…

No previous empirical study has investigated whether the learning disabilities (LD) identification decisions of proposed methods to operationalize processing strengths and weaknesses approaches for LD identification are associated with differential treatment response. We investigated whether the identification decisions of the…

This article demonstrates how the broad and narrow abilities and processes that comprise Cattell-Horn-Carroll (CHC) theory and their relations to specific academic outcomes have begun to transform our current understanding of the definition of and methods for identifying specific learning disability (SLD), particularly in the school setting. The…

Emotional and cognitive factors were examined in 18 children with mathematical learning disabilities (MLD), compared with 18 normally achieving children, matched for chronological age, school level, gender and verbal IQ. Working memory, short-term memory, inhibitory processes, speed of processing and level of anxiety in mathematics were assessed…

This study tests the hypothesis that dyslexia and dyscalculia are associated with two largely independent cognitive deficits, namely a phonological deficit in the case of dyslexia and a deficit in the number module in the case of dyscalculia. In four groups of 8- to 10-year-olds (42 control, 21 dyslexic, 20 dyscalculic, and 26…

Two methodological problems often arising in dyslexia research are considered. The first problem concerns the validity of experimental measures and the related problem of interpreting null results. The second problem involves the effects of sampling from a disabled population if the disorder under investigation has multiple unknown origins.…

Response to intervention (RTI) must be combined with comprehensive cognitive assessment to identify children with learning disabilities. This article presents the Cognitive Hypothesis Testing (CHT) model for integrating RTI and comprehensive evaluation practices in the identification of children with reading disabilities. The CHT model utilizes a…

Representational competence refers to the individual's capability to respond appropriately to external representations. For example, a child engaged in a grouping task may collect together all like objects even if the group contains varying representations of the object, including (1) the object itself, (2) a three-dimensional likeness of the…