dyscalculia – the neglected learning disorder karin landerl university of graz

DyscalculiaDyscalculia – – the neglected learning disorderthe neglected learning disorder

Karin LanderlKarin Landerl

University of GrazUniversity 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 GoldbergTom Cruise Thomas Edison

Swedish Royal Family Greg LouganisJackie Stewart Michelangelo Pablo Picasso August RodinNelson 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 %

OverviewOverview

What is dyscalculia?What is dyscalculia?

Neuro-cognitive theories of learning Neuro-cognitive theories of learning disordersdisorders

Core deficits in processing numerositiesCore deficits in processing numerosities

Implications for diagnosis and interventionImplications 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 .Case description .

in elementary school, I didn´t understand for a long time in elementary school, I didn´t understand for a long time why 1 + 1 = 2 why 1 + 1 = 2 –– I thought it should be 11 I thought it should be 11

I always had problems when new concepts or procedures I always had problems when new concepts or procedures were introduced, I was insecure and didn´t get it. Only were introduced, I was insecure and didn´t get it. Only when we were almost through and everzbody else when we were almost through and everzbody else understood, I sometimes got a basic idea, understood understood, I sometimes got a basic idea, understood maybe half of it. Still, I mostly learned procedures by maybe half of it. Still, I mostly learned procedures by heart, without really understanding. If there was only a heart, without really understanding. If there was only a small change in the problems given, I was again small change in the problems given, I was again completely lost. completely lost.

I never understood I never understood word problemsword problems –– still don still don´t. I just don´t get what I´m supposed to ´t. I just don´t get what I´m supposed to dodo

I cannot visualise amounts or magnitudes. I cannot visualise amounts or magnitudes. How much are 100 g? I just don´t have it How much are 100 g? I just don´t have it in my head. in my head.

I cannot convert I cannot convert –– for example grams in for example grams in kilograms. So I have problems to bake a kilograms. So I have problems to bake a cake when the recipe has other measures cake when the recipe has other measures than what I needthan what I need


I am poor in mental calculationsI am poor in mental calculations…… most often I keep most often I keep counting in my head. For example, when I´m asked counting in my head. For example, when I´m asked to add up 16 + 18, I can do 10 + 10 alright to add up 16 + 18, I can do 10 + 10 alright –– that´s that´s 20. But the 6 and the 8 are difficult then, that takes 20. But the 6 and the 8 are difficult then, that takes longer. I need to add them to the 20 and at the longer. I need to add them to the 20 and at the same time remembersame time remember…… and when it gets more and when it gets more diffcult with divisions or so, I give up completely. diffcult with divisions or so, I give up completely.

I still count on my fingers I still count on my fingers –– if anybody is watching me, if anybody is watching me, I try to do it in my head. I try to do it in my head.


I have problems with percentages I have problems with percentages –– they just they just don´t mean anything to me.don´t mean anything to me.

Decimals I find especially hard Decimals I find especially hard –– adding or adding or subtracting them subtracting them –– oh my god oh my god –– there´s only there´s only chaos in my brain chaos in my brain

I don´t realise it when I come up with a I don´t realise it when I come up with a completely incorrect result, because the completely incorrect result, because the numbers don´t mean anything to me, I numbers don´t mean anything to me, I cannot estimate if my result might be right cannot estimate if my result might be right or wrongor wrong


or to remember things like: "were there or to remember things like: "were there 600 or 6000 people at the festival?". I 600 or 6000 people at the festival?". I cannot cannot estimateestimate the number of the number of inhabitants of some place, it just doen´t inhabitants of some place, it just doen´t mean anything to me. Are there 10.000 mean anything to me. Are there 10.000 people living in Germany or was it people living in Germany or was it 100.000 or more or less? I don´t have a 100.000 or more or less? I don´t have a clue.clue.


10000 - 204 =10000 - 204 = First, I needed to think how to calculate First, I needed to think how to calculate

10000 - 204. At some point I decided to do 10000 - 204. At some point I decided to do 10000 - 100 = 9000 and then again 10000 - 100 = 9000 and then again subtract 100 = 8000. and then there´s subtract 100 = 8000. and then there´s only 4 left of the 204, which I needed to only 4 left of the 204, which I needed to subtract. It was easy to write down 79, subtract. It was easy to write down 79, same with the following 9 (799), though a same with the following 9 (799), though a bit slower, and then the 6. So the result is bit slower, and then the 6. So the result is 7996. I have no idea if this could be 7996. I have no idea if this could be correct as I don´t have my calculator with correct as I don´t have my calculator with me. me.

Neurocognitive Theories of Neurocognitive Theories of Inborn Core MechanismsInborn 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 What is the critical core mechanism of dyslexia?mechanism of dyslexia?

Phonological processingPhonological processing Enables fast-track learning of language Enables fast-track learning of language

and literacyand literacy

Phonological deficits – delay in language Phonological deficits – delay in language development and serious problems in development and serious problems in

reading acquisitionreading acquisitionLearning is slow and compensatoryLearning is slow and compensatory

Is there a core Is there a core mechanism for mechanism for

arithmetic skills?arithmetic skills?

Same as for dyslexia?Same as for dyslexia?

Population

based

sample N

% of

2586 Percent of N

Arithmetic disorder + AD + RD + SD

158 6.1 25.9 37.3

Reading disorder

181 7.0 22.7

Spelling disorder

228 8.8 25.9

Landerl & Moll (2010), Journal of Child Psychology and Psychiatry

0

20

40

60

80

100

% c

orre

ct

control dyslexia dyscalculia dyslexia/dyscalculia

„Say /ti:k/ without /k/“

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

Phonological awareness?Phonological awareness?

Naming Speed for DigitsNaming Speed for Digits

40

60

80

100

120

140

dig

its /

min

control dyslexia dyscalculia combined


Babies process numerosties

Starr, Libertus, & Brannon (2013) PNAS

Babies process numerosities

Xu, Spelke & Goddard (2006)

Babies can do simple Babies can do simple arithmeticarithmetic

Wynn (1992)Wynn (1992)

Babies are attentive towards numerosities Babies are attentive towards numerosities = core system= core system

number sense – Dehaene (1997)number sense – Dehaene (1997)

number module – Butterworth (1999)number module – Butterworth (1999)

Dysfunctional core systemDysfunctional core systematypical development of the cognitive atypical development of the cognitive

representation of numbers representation of numbers DYSCALCULIADYSCALCULIA

Deficits in numerical processing Deficits in numerical processing in dyscalculiain dyscalculia::

Magnitude comparisonMagnitude comparison

Magnitude comparisonMagnitude comparison

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

Arabic numbers = symbols for Arabic numbers = symbols for numerositiesnumerosities

2 8

32 58

Number comparison – Requires access to the magnitudes represented by the symbols

Number comparisonNumber comparison


Basic numerical processing Basic numerical processing as a core deficit of as a core deficit of

dyscalculiadyscalculiaN – Numerical comparison

5 7

P – Physical comparison

(neutral condition): 5 5

Comparison of two-digit Comparison of two-digit numbersnumbers

Compatible: 52 76 incompatible: 47 62

Landerl (2013) Frontiers in Psychology

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

0

500

1000

1500

2000

2500

3000

3500

4000

4500

1 2 3 4 5 6 7 8

Number of dots

RT

Grade 2 dyscalculic Grade 2 control



Butterworth (1999)

Everybody counts…Everybody counts…

Verbal skills

Visual-spatial skills Problem solving skills

Long term memory

attention

Arithmetic skills

Arithmetic skills

teaching intervention

Biology

Cognition

Behaviour

basic numerical skillsreading

Executive functions

Working memory

Mental number line

Visual-arabicrepresentation

Auditory-verbalrepresentation

Read/write/compare Arabic

numbers

Subitizing estimation

Number factsWritten

calculations

Biology

Cognition

Behaviour

IPS

stimulationteachingintervention

Finger-representation

Finger-calculationcounting

magnitude comparison

Analog magnitude representatio

Process number words

Basic numerical skills

Schematische Darstellung der in der Literatur postulierten (und zum Teil noch kontrovers diskutierten) neuronalen Netzwerkkomponenten der

Zahlenverarbeitung und des Rechnens

Präfrontale Areale : Monitoring,

Arbeitsgedächtnis, Strategien etc

SMA (Supplementär-motorisches Areal): antwortbezogene Konflikt-

resolution, ev. Fingerrechnen

Posteriorer IPS und (H)IPS: R epräsentation des Basis-10-

(Platz x Wert) Systems

SMA (Supplementär-motorisches Areal): antwortbezogene Konflikt-

resolution, ev. FingerrechnenPräfrontale Areale :

Monitoring, Arbeitsgedächtnis,

Strategien etc

Perisylvische Areale:

Zählsequenzen, Benennen von

Zahlen, verbales Rechnen

Gyrus angularis: Faktenabruf (v.a. Multiplikations-

fakten)

Cerebellum: Aufgaben mit hoher Komplexität und/oder Neuheitswert

(domänen-unspezifisch), eventuell auch Zählsequenzen

Gyrus fusiformis: visuelle Verarbeitung von Wörtern / ev.

Arabischen Zahlen

HIPS (horizontales Segment d. intraparietalen Sulcus): mentale

Mengen-repräsentation per se

PSPL (Posteriorer superiorer parietaler Lappen): räumliche

Aufmerksamkeit auf der mentalen Zahlenlinie

Kaufmann & Nuerk (2007; Abb. 1)

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-Specialization of the neuro-cognitive network for cognitive network for

numbers/arithmetic happens during numbers/arithmetic happens during developmentdevelopment

Rivera et al. (2005)

Areas whose activation increases with age

Areas whose activation decreases with age

Doing arithmetic requires a highly Doing arithmetic requires a highly specified neuro-cognitive networkspecified neuro-cognitive network

The starting point for the development of The starting point for the development of this network is an early core mechanism this network is an early core mechanism

The development and specification of the The development and specification of the neuro-cognitve network for arithmetic neuro-cognitve network for arithmetic takes many years and is strongly takes many years and is strongly dependent on environmental factors dependent on environmental factors (stimulation, teaching, intervention)(stimulation, teaching, intervention)

SummarySummary

DyscalculiaDyscalculia Inborn core mechanism is not functioning properlyInborn core mechanism is not functioning properly

„„Everybody counts, but not everybody understands Everybody counts, but not everybody understands numbers“ (Butterworth, 2005)numbers“ (Butterworth, 2005)

Development of the neuro-cognitive network underlying Development of the neuro-cognitive network underlying arithmetic is atypical, right from start. Learning is slow arithmetic is atypical, right from start. Learning is slow and compensatoryand compensatory

Early identification and intervention is important in order Early identification and intervention is important in order to support learning and avoid secondary symptoms to support learning and avoid secondary symptoms (maths anxiety, behavioural problems)(maths anxiety, behavioural problems)

Establish a profile of strengths and weaknesses in Establish a profile of strengths and weaknesses in arithmetic and numerical processing as well as arithmetic and numerical processing as well as other ressources (and comorbidities)other ressources (and comorbidities)

Tailored intervention based on fine-grained Tailored intervention based on fine-grained diagnosisdiagnosis

Learning will often be compensatory and take Learning will often be compensatory and take more timemore time

Implications for diagnosis and Implications for diagnosis and interventionintervention

dyscalculia – the neglected learning disorder karin landerl university of graz

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