Impaired parietal magnitude processing in developmental dyscalculia

Abstract

Developmental dyscalculia (DD) is a specific learning disability affecting the acquisition of school-level mathematical abilities in the context of otherwise normal academic achievement, with prevalence estimates in the order of 3-6%. Behavioural studies show deficits in elementary numerical processing among individuals with pure DD, indicating that deficits in higher-level mathematical skills may stem from impaired representation and processing of basic numerical magnitude. Adult neuropsychological and neuroimaging research points to the intraparietal sulcus as a key region for the representation and processing of numerical magnitude. This raises the possibility of a parietal dysfunction as a root cause of DD. We show that, in children with pure DD, the right intraparietal sulcus is not modulated in response to numerical processing demands to the same degree as in typically developing children. This finding provides the first direct evidence for a specific impairment of parietal magnitude systems in DD during non-symbolic numerosity processing.

Nature and origins of mathematics difficulties in very preterm children: a different etiology than developmental dyscalculia

“…Deficits in basic numerical representations associated with developmental dyscalculia have been linked with structural and functional abnormalities in the bilateral intraparietal sulci (22). In contrast, brain development after very preterm birth has been described as an amalgam of developmental and destructive influences associated with complex neurocognitive deficits (23).…”

Defective number module or impaired access? Numerical magnitude processing in first graders with mathematical difficulties

“…Moreover, structural (Isaacs, Edmonds, Lucas, & Gadian, 2001;Rotzer et al, 2008) and functional (Mussolin et al, 2010;Price, Holloway, Rasanen, Vesterinen, & Ansari, 2007) There exists considerable evidence that representations of magnitude are impaired in children with mathematical difficulties (De Smedt, Reynvoet, et al, 2009;Geary et al, 2007Geary et al, , 2008Iuculano et al, 2008;Jordan, Kaplan, Olah, & Locuniak, 2006;Landerl et al, 2004Passolunghi & Siegel, 2004;Rousselle & Noël, 2007). However, the majority of these studies only relied on tasks with a symbolic processing requirement and do not allow us to clarify whether difficulties in mathematics result from difficulties in representing numerical magnitudes, as postulated in the defective number module hypothesis, or from difficulties in the ability to access numerical magnitudes from formal symbols, such as Arabic numerals, as assumed in the access deficit hypothesis.…”

Processing Ordinality and Quantity: The Case of Developmental Dyscalculia

“…Price and colleagues [46] for example, found differences between DD and controls in symbolic comparisons in an fMRI study. Specifically, the difference was found in brain activation but not in the behavioral results.…”

“…These deficiencies can be found at the structural [40,41] and the functional levels alike (DD in children - [42,43],number line training: [44,45,46]); (DD in adults - [47]). The existing brain development imaging literature on DD that focuses on non-symbolic number processing (e.g., comparing the numerosity of two groups of dot patterns) is inconclusive.…”

“…The existing brain development imaging literature on DD that focuses on non-symbolic number processing (e.g., comparing the numerosity of two groups of dot patterns) is inconclusive. Studies have demonstrated processing differences between children with and without DD (e.g., [46]) as well as the absence of such differences (e.g., [43]). …”