scholarly journals Magnitude Processing in Developmental Dyscalculia : A Heterogeneous Learning Disability with Different Cognitive Profiles

2016 ◽  
Author(s):  
Kenny Skagerlund ◽  
2015 ◽  
Vol 223 (2) ◽  
pp. 69-82 ◽  
Author(s):  
Jörg-Tobias Kuhn

Developmental dyscalculia (DD) is a specific learning disorder that affects the acquisition of arithmetic skills and number processing in children. A high comorbidity between DD and other neurodevelopmental disorders (e.g., dyslexia, attention-deficit/hyperactivity disorder [ADHD]) as well as substantial heterogeneity in cognitive profiles have been reported. Current studies indicate that DD is persistent, has a genetic component, and is related to functional and structural alterations of brain areas involved in magnitude representation. Recent neuronal and behavioral evidence is presented, showing that DD entails (a) impairments in two preverbal core systems of number, an approximate system for estimating larger magnitudes and an exact system for representing small magnitudes, (b) deficits in symbolic number processing, (c) aberrant and nonadaptive neuronal activation in basic magnitude processing and calculation, (d) dysfunctional arithmetic fact retrieval and persistent use of counting strategies in calculation, and (e) deficits in visuospatial working memory and the central executive. Finally, open research questions, including the role of domain-general cognitive resources in DD, causes and developmental consequences of comorbidity, as well as design and evaluation of interventions for DD, are briefly discussed.


2014 ◽  
Vol 49 (3) ◽  
pp. 240-256 ◽  
Author(s):  
Tammy D. Tolar ◽  
Lynn Fuchs ◽  
Jack M. Fletcher ◽  
Douglas Fuchs ◽  
Carol L. Hamlett

2017 ◽  
Vol 51 (6) ◽  
pp. 600-611 ◽  
Author(s):  
Alice De Visscher ◽  
Marie-Pascale Noël ◽  
Mauro Pesenti ◽  
Valérie Dormal

Numerous studies have tried to identify the core deficit of developmental dyscalculia (DD), mainly by assessing a possible deficit of the mental representation of numerical magnitude. Research in healthy adults has shown that numerosity, duration, and space share a partly common system of magnitude processing and representation. However, in DD, numerosity processing has until now received much more attention than the processing of other non-numerical magnitudes. To assess whether or not the processing of non-numerical magnitudes is impaired in DD, the performance of 15 adults with DD and 15 control participants was compared in four categorization tasks using numerosities, lengths, durations, and faces (as non-magnitude-based control stimuli). Results showed that adults with DD were impaired in processing numerosity and duration, while their performance in length and face categorization did not differ from controls’ performance. Our findings support the idea of a nonsymbolic magnitude deficit in DD, affecting numerosity and duration processing but not length processing.


2010 ◽  
Vol 22 (5) ◽  
pp. 860-874 ◽  
Author(s):  
Christophe Mussolin ◽  
Anne De Volder ◽  
Cécile Grandin ◽  
Xavier Schlögel ◽  
Marie-Cécile Nassogne ◽  
...  

Developmental dyscalculia (DD) is a deficit in number processing and arithmetic that affects 3–6% of schoolchildren. The goal of the present study was to analyze cerebral bases of DD related to symbolic number processing. Children with DD aged 9–11 years and matched children with no learning disability history were investigated using fMRI. The two groups of children were controlled for general cognitive factors, such as working memory, reading abilities, or IQ. Brain activations were measured during a number comparison task on pairs of Arabic numerals and a color comparison task on pairs of nonnumerical symbols. In each task, pairs of stimuli that were close or far on the relevant dimension were constituted. Brain activation in bilateral intraparietal sulcus (IPS) was modulated by numerical distance in controls but not in children with DD. Moreover, although the right IPS responded to numerical distance only, the left IPS was influenced by both numerical and color distances in control children. Our findings suggest that dyscalculia is associated with impairment in areas involved in number magnitude processing and, to a lesser extent, in areas dedicated to domain-general magnitude processing.


2007 ◽  
Vol 17 (24) ◽  
pp. R1042-R1043 ◽  
Author(s):  
Gavin R. Price ◽  
Ian Holloway ◽  
Pekka Räsänen ◽  
Manu Vesterinen ◽  
Daniel Ansari

2001 ◽  
Vol 34 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Ruth S. Shalev ◽  
Orly Manor ◽  
Batsheva Kerem ◽  
Mady Ayali ◽  
Navah Badichi ◽  
...  

2012 ◽  
Vol 15 (3) ◽  
pp. 952-966 ◽  
Author(s):  
Danilka Castro Cañizares ◽  
Vivian Reigosa Crespo ◽  
Eduardo González Alemañy

The aim of this study was to evaluate if children with Developmental Dyscalculia (DD) exhibit a general deficit in magnitude representations or a specific deficit in the connection of symbolic representations with the corresponding analogous magnitudes. DD was diagnosed using a timed arithmetic task. The experimental magnitude comparison tasks were presented in non-symbolic and symbolic formats. DD and typically developing (TD) children showed similar numerical distance and size congruity effects. However, DD children performed significantly slower in the symbolic task. These results are consistent with the access deficit hypothesis, according to which DD children's deficits are caused by difficulties accessing magnitude information from numerical symbols rather than in processing numerosities per se.


Sign in / Sign up

Export Citation Format

Share Document