Dyscalculia – the neglected learning disorder Karin Landerl University of Graz

(Pubmed Database) Dyscalculia – the neglected learning disorder

Hans Christian Andersen John Irving Agatha Christie Cher Winston Churchill Leonardo DaVinci Charles Darwin Walt Disney Whoopi Goldberg Tom Cruise Thomas Edison Swedish Royal Family Greg Louganis Jackie Stewart Michelangelo Pablo Picasso August Rodin Nelson Rockefeller Franklin Roosevelt Vincent VanGogh Woodrow Wilson Celebrities with dyslexia Celebrities with dyscalculia??

Prevalence rates: Studies in GB, Germany, Greece, India, Israel ( Badian, 1983; Gross-Tsur, Manor, & Shalev, 1996; Hein, Bzufka & Neumärker, 2000; Klauer, 1992; Kosc, 1974; Koumoula, Tsironi, Starmouli, Bardani & Siapati, 2004; Lewis, Hitch & Walker, 1994; Ramaa & Gowaramma, 2002; von Aster, Schweiter & Weinhold Zulauf, 2007) No clear gender differences Comparable prevalence rates ranging from 3 to 8.3 %

Overview  What is dyscalculia?  Neuro-cognitive theories of learning disorders  Core deficits in processing numerosities  Implications for diagnosis and intervention

Definition: (ICD-10) "...a condition that affects the ability to acquire arithmetical skills. Dyscalculic learners may have difficulty understanding simple number concepts, lack an intuitive grasp of numbers, and have problems learning number facts and procedures. Even if they produce a correct answer or use a correct method, they may do so mechanically and without confidence" (UK Department for Education and Science, 2001). DYSCALCULIA

Case description. in elementary school, I didn´t understand for a long time why = 2 – I thought it should be 11 I always had problems when new concepts or procedures were introduced, I was insecure and didn´t get it. Only when we were almost through and everzbody else understood, I sometimes got a basic idea, understood maybe half of it. Still, I mostly learned procedures by heart, without really understanding. If there was only a small change in the problems given, I was again completely lost.

I never understood word problems – still don´t. I just don´t get what I´m supposed to do I cannot visualise amounts or magnitudes. How much are 100 g? I just don´t have it in my head. I cannot convert – for example grams in kilograms. So I have problems to bake a cake when the recipe has other measures than what I need Case description.

I am poor in mental calculations … most often I keep counting in my head. For example, when I´m asked to add up , I can do alright – that´s 20. But the 6 and the 8 are difficult then, that takes longer. I need to add them to the 20 and at the same time remember … and when it gets more diffcult with divisions or so, I give up completely. I still count on my fingers – if anybody is watching me, I try to do it in my head. Case description.

I have problems with percentages – they just don´t mean anything to me. Decimals I find especially hard – adding or subtracting them – oh my god – there´s only chaos in my brain I don´t realise it when I come up with a completely incorrect result, because the numbers don´t mean anything to me, I cannot estimate if my result might be right or wrong Case description.

or to remember things like: "were there 600 or 6000 people at the festival?". I cannot estimate the number of inhabitants of some place, it just doen´t mean anything to me. Are there people living in Germany or was it or more or less? I don´t have a clue. Case description.

=  First, I needed to think how to calculate At some point I decided to do = 9000 and then again subtract 100 = and then there´s only 4 left of the 204, which I needed to subtract. It was easy to write down 79, same with the following 9 (799), though a bit slower, and then the 6. So the result is I have no idea if this could be correct as I don´t have my calculator with me.

Neurocognitive Theories of Inborn Core Mechanisms  Babies are born with a number of simple core mechanisms that are critical for further development  These inborn core mechanisms enable fast-track learning (with normal environmental stimulation)  What happens if the core mechanism doesn´t function properly?  Developmental disorder

What is the critical core mechanism of dyslexia? Phonological processing Enables fast-track learning of language and literacy Phonological deficits – delay in language development and serious problems in reading acquisition Learning is slow and compensatory

Is there a core mechanism for arithmetic skills?

Same as for dyslexia?

„Say /ti:k/ without /k/“ Landerl, Fussenegger, Moll & Willburger (2009), Journal of Experimental Child Psychology Phonological awareness?

Naming Speed for Digits Landerl, Fussenegger, Moll & Willburger (2009), Journal of Experimental Child Psychology

Babies process numerosties Starr, Libertus, & Brannon (2013) PNAS

Babies process numerosities Xu, Spelke & Goddard (2006)

Babies can do simple arithmetic

 Wynn (1992)

Babies are attentive towards numerosities = core system number sense – Dehaene (1997) number module – Butterworth (1999) Dysfunctional core system  atypical development of the cognitive representation of numbers  DYSCALCULIA

Deficits in numerical processing in dyscalculia: Magnitude comparison

Magnitude comparison Lese-Kontrast: Gruppe: F < 1, n.s.

Arabic numbers = symbols for numerosities Number comparison – Requires access to the magnitudes represented by the symbols

Number comparison Landerl, Fussenegger, Moll & Willburger (2009), Journal of Experimental Child Psychology

Basic numerical processing as a core deficit of dyscalculia N – Numerical comparison 5 7 P – Physical comparison (neutral condition): 5 5

Comparison of two-digit numbers Compatible: 52 76incompatible: Landerl (2013) Frontiers in Psychology

Dot counting ( Schleifer & Landerl, 2011, Developmental Science )

Butterworth (1999)

Everybody counts…

Verbal skills Visual-spatial skills Problem solving skills Long term memory attention Arithmetic skills teaching intervention Biology Cognition Behaviour basic numerical skills reading Executive functions Working memory

Mental number line Visual-arabic representation Auditory-verbal representation Read/write/compa re Arabic numbers Subitizing estimation Number facts Written calculations Biology Cognition Behaviour IPS stimulation teaching intervention Finger- representation Finger- calculation counting magnitude comparison     Analog magnitude representatio Process number words Basic numerical skills

Brain areas that have been identified to be active during numerical processing /arithmetic

Dyslexia: under-activation in left temporo-parietal areas Paulesu et al. (2001) Dyscalculia: under-activation in intraparietal sulcus (bilaterally) Molko et al. (2003) Dyscalculia and Dyslexia : different neuro-functional abnormalities

Specialization of the neuro- cognitive network for numbers/arithmetic happens during development Rivera et al. (2005) Areas whose activation increases with age Areas whose activation decreases with age

 Doing arithmetic requires a highly specified neuro-cognitive network  The starting point for the development of this network is an early core mechanism  The development and specification of the neuro-cognitve network for arithmetic takes many years and is strongly dependent on environmental factors (stimulation, teaching, intervention) Summary

Dyscalculia  Inborn core mechanism is not functioning properly „Everybody counts, but not everybody understands numbers“ (Butterworth, 2005)  Development of the neuro-cognitive network underlying arithmetic is atypical, right from start. Learning is slow and compensatory  Early identification and intervention is important in order to support learning and avoid secondary symptoms (maths anxiety, behavioural problems)

 Establish a profile of strengths and weaknesses in arithmetic and numerical processing as well as other ressources (and comorbidities)  Tailored intervention based on fine-grained diagnosis  Learning will often be compensatory and take more time Implications for diagnosis and intervention