Longitudinal Brain Development of Numerical Skills in Typically Developing Children and Children with Developmental Dyscalculia.

Ursina Mccaskey,Michael Von Aster,Ruth O'Gorman Tuura,Karin Kucian,Ernst Martin,Urs Maurer

doi:10.3389/fnhum.2017.00629

Abstract

Developmental dyscalculia (DD) is a learning disability affecting the acquisition of numerical-arithmetical skills. Studies report persistent deficits in number processing and aberrant functional activation of the fronto-parietal numerical network in DD. However, the neural development of numerical abilities has been scarcely investigated. The present paper provides a first attempt to investigate behavioral and neural trajectories of numerical abilities longitudinally in typically developing (TD) and DD children. During a study period of 4 years, 28 children (8–11 years) were evaluated twice by means of neuropsychological tests and a numerical order fMRI paradigm. Over time, TD children improved in numerical abilities and showed a consistent and well-developed fronto-parietal network. In contrast, DD children revealed persistent deficits in number processing and arithmetic. Brain imaging results of the DD group showed an age-related activation increase in parietal regions (intraparietal sulcus), pointing to a delayed development of number processing areas. Besides, an activation increase in frontal areas was observed over time, indicating the use of compensatory mechanisms. In conclusion, results suggest a continuation in neural development of number representation in DD, whereas the neural network for simple ordinal number estimation seems to be stable or show only subtle changes in TD children over time.

Highlights

How does the “numerical brain” develop? Numbers are omnipresent in our lives and our innate ability to detect small numerosities enables us to develop complex mathematical skills at a young age (Starkey et al, 1990; Xu and Spelke, 2000; Izard et al, 2009)
With functional Magnetic Resonance Imaging (fMRI) we investigated the ordinal aspect of number processing, as differences between Developmental dyscalculia (DD) and typically developing (TD) children have been reported in parietal and domain general regions during a numerical order task (Kucian et al, 2011a)
Every child in the DD group scored under the threshold value of 67 points in the BASISMATH and still fulfilled the diagnostic criteria for DD at the follow-up

Summary

Introduction

How does the “numerical brain” develop? Numbers are omnipresent in our lives and our innate ability to detect small numerosities enables us to develop complex mathematical skills at a young age (Starkey et al, 1990; Xu and Spelke, 2000; Izard et al, 2009). Numerical Brain Development number representation (Landerl et al, 2004; Rousselle and Noël, 2007; Mussolin et al, 2010; Landerl, 2013). Those skills are assumed to predict later arithmetical achievement (Halberda et al, 2008; De Smedt et al, 2009; Geary et al, 2012; Träff, 2013) and are essential for the development of numeracy. The fact that difficulties in numeracy result in reduced employment opportunities and high public costs underscores the importance of understanding more about numerical brain development (Parsons and Bynner, 2005; Gross, 2009)

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