Severe Developmental Dyscalculia Is Characterized by Core Deficits in Both Symbolic and Nonsymbolic Number Sense

Decarli, Gisella; Sella, Francesco; Lanfranchi, Silvia; Gerotto, Giulia; Gerola, Silvia; Cossu, Giuseppe; Zorzi, Marco

doi:10.1177/09567976221097947

Cited by 24 publications

(16 citation statements)

References 39 publications

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“…it fosters the process of magnitude-to-symbol mapping, leading children to attribute meaning to number words and to map them into their pre-existing representations of coarse magnitudes. This is also in line with previous reports of a deficit in the ANS in children with developmental dyscalculia (e.g., Decarli et al, 2020;Decarli et al, 2023;Piazza et al, 2010) and of a benefit in arithmetic tasks after an ANS training (e.g., Park & Brannon, 2013 but see also Szkudlarek et al, 2021 for failure to observe it). Importantly, we also tested for the specificity of the longitudinal ANS-to-maths link by including, both at T1 and at T2, control perceptual tests of perceptual non-numerical skills.…”

Section: Discussionsupporting

confidence: 92%

Number sense at 12 months predicts 4‐year‐olds’ maths skills

Decarli

Zingaro

Surian

et al. 2023

Developmental Science

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Preverbal infants spontaneously represent the number of objects in collections. Is this ‘sense of number’ (also referred to as Approximate Number System, ANS) part of the cognitive foundations of mathematical skills? Multiple studies reported a correlation between the ANS and mathematical achievement in children. However, some have suggested that such correlation might be mediated by general‐purpose inhibitory skills. We addressed the question using a longitudinal approach: we tested the ANS of 60 12 months old infants and, when they were 4 years old (final N = 40), their symbolic math achievement as well as general intelligence and inhibitory skills. Results showed that the ANS at 12 months is a specific predictor of later maths skills independent from general intelligence or inhibitory skills. The correlation between ANS and maths persists when both abilities are measured at four years. These results confirm that the ANS has an early, specific and longstanding relation with mathematical abilities in childhood.Research Highlights In the literature there is a lively debate about the correlation between the ANS and maths skills. We longitudinally tested a sample of 60 preverbal infants at 12 months and rested them at 4 years (final sample of 40 infants). The ANS tested at 12 months predicted later symbolic mathematical skills at 4 years, even when controlling for inhibition, general intelligence and perceptual skills. The ANS tested at 4 years remained linked with symbolic maths skills, confirming this early and longstanding relation in childhood.

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Section: Discussionsupporting

confidence: 92%

Number sense at 12 months predicts 4‐year‐olds’ maths skills

Decarli

Zingaro

Surian

et al. 2023

Developmental Science

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“…The key causes of DD continue to be debated (e.g., Decarli et al, 2023 ). While some authors assume that domain-general deficits play a key role (e.g., Geary, 2004 ), others suppose that deficits in domain-specific skills, especially in basic numerical skills, lie at the core of DD (e.g., Butterworth, 2010 ).…”

Section: Introductionmentioning

confidence: 99%

Delayed development of basic numerical skills in children with developmental dyscalculia

Lamb,

Krieger,

Kuhn

2024

Front. Psychol.

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Research suggests that children with developmental dyscalculia (DD) have deficits in basic numerical skills. However, there is conflicting evidence on whether basic numerical skills in children with DD are qualitatively different from those in typically developing children (TD) or whether basic numerical skills development in children with DD is simply delayed. In addition, there are also competing hypotheses about deficits in basic numerical skills, assuming (1) a general deficit in representing numerosities (Approximate Number System, ANS), (2) specific deficits in an object-based attentional system (Object Tracking System, OTS), or (3) deficits in accessing numerosities from symbols (Access Deficit, AD). Hence, the purpose of this study was to investigate whether deficits in basic numerical skills in children with DD are more indicative of a developmental delay or a dyscalculia-specific qualitative deviation and whether these deficits result from (selective) impairment of core cognitive systems involved in numerical processing. To address this, we tested 480 children (68 DD and 412 TD) in the 2nd, 3rd, and 4th grades with different paradigms for basic numerical skills (subitizing, counting, magnitude comparison tasks, number sets, and number line estimation tasks). The results revealed that DD children’s impairments did not indicate qualitatively different basic numerical skills but instead pointed to a specific developmental delay, with the exception of dot enumeration. This result was corroborated when comparing mathematical profiles of DD children in 4th grade and TD children in 2nd grade, suggesting that DD children were developmentally delayed and not qualitatively different. In addition, specific deficits in core markers of numeracy in children with DD supported the ANS deficit rather than the AD and OTS deficit hypothesis.

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“…Some hints come from the literature on the role of visual numerosity perception (dot arrays). Although most animal species are capable of some form of numerosity estimation ( Butterworth, 2022 ), it appears that in humans numerosity estimation may act as a non-symbolic precursor for the development of symbolic mathematical skills ( Chen and Li, 2014 ; Decarli et al, 2023 ; Halberda et al, 2008 ; Mazzocco et al, 2011 ; Piazza, 2010 ; Piazza et al, 2010 ; Schneider et al, 2017 ). The sensorimotor system could act as an early tool to constantly update and calibrate motor and sensory systems for the encoding and active manipulation of quantities and objects, with a potential impact on the quality of formal mathematical skills in later development.…”

Section: Discussionmentioning

confidence: 99%

Sensorimotor mechanisms selective to numerosity derived from individual differences

Anobile,

Petrizzo,

Paiardini

et al. 2024

eLife

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We have previously shown that after few seconds of adaptation by finger-tapping, the perceived numerosity of spatial arrays and temporal sequences of visual objects displayed near the tapping region is increased or decreased, implying the existence of a sensorimotor numerosity system (Anobile et al., 2016). To date, this mechanism has been evidenced only by adaptation. Here we extend our finding by leveraging on a well-established covariance technique, used to unveil and characterize “channels” for basic visual features such as colour, motion, contrast, and spatial frequency. Participants were required to press rapidly a key a specific number of times, without counting. We then correlated the precision of reproduction for various target number presses between participants. The results showed high positive correlations for nearby target numbers, scaling down with numerical distance, implying tuning selectivity. Factor analysis identified two factors, one for low and the other for higher numbers. Principal component analysis revealed two bell-shaped covariance channels, peaking at different numerical values. Two control experiments ruled out the role of non-numerical strategies based on tapping frequency and response duration. These results reinforce our previous reports based on adaptation, and further suggest the existence of at least two sensorimotor number channels responsible for translating symbolic numbers into action sequences.

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Severe Developmental Dyscalculia Is Characterized by Core Deficits in Both Symbolic and Nonsymbolic Number Sense

Cited by 24 publications

References 39 publications

Number sense at 12 months predicts 4‐year‐olds’ maths skills

Number sense at 12 months predicts 4‐year‐olds’ maths skills

Delayed development of basic numerical skills in children with developmental dyscalculia

Sensorimotor mechanisms selective to numerosity derived from individual differences

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