Fiona Simmons: Dyslexia, Dyscalculia and Mathematics Difficulties

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Dyslexia, dyscalculia & mathematics difficultiesDr Fiona Simmons Liverpool John Moores University [email protected]
Overview The association between mathematics difficulties and dyslexia The cognitive underpinnings of maths difficulties Assessment implications
Maths difficulties & dyslexia Early studies suggested that only a proportion of dyslexic children had maths difficulties Joffe (1981) 10% of dyslexic children scored well above expectations, 60% scored well below expectations on a test of written arithmetic Frequent comorbidity of dyslexia and mathematics difficulties (Dirks, Spyer, Van Lieshout, & de Sonneville, 2008; Miles, Haslum, & Wheeler, 2001; Von Aster, 2000) However, the extent that maths difficulties coexist with dyslexia depends on what maths measures are used Miles (1983) found that difficulty recalling multiplication facts was characteristic of dyslexia
Investigating maths profiles of dyslexic children Simmons & Singleton (2009) On average dyslexic children were Slower and less accurate at recalling arithmetic facts Slower counters Performing at a similar level to their peers at a magnitude comparison task Suggests that typically dyslexic children have an unbalanced profile of mathematical skills Recent study replicates difficulty with arithmetic facts (Boets & De Smedt, 2010)
Cognitive underpinningsDomain general explanations Phonological processing Visual memory Central executive processing ANS Domain specific explanations Number module
PNS
Phonological processingBiological Cognitive Functional disconnection of the left angular gyrus Weak phonological representationsSlow RAN Poor phonological loop function Poor phonological awareness
Behavioural
Simmons & Singleton (2008)
Slow & inaccurate reading & spelling Circumscribed mathematics difficulties particularly with number facts
Support for role of phonological processing Neuropsychological studies indicate 3 areas for mathematical processing (Dehaene et al., 1999, 2003) Independent predictors of arithmetic development Phonological loop function (Hecht et al., 2001; Noel et al, 2004; Rasmussen & Bisanz, 2005) Rapid Automatic Naming (Hecht et al.,2001) Phonological awareness (DeSmedt et al., in press;Fuchs et al., 2005; Hecht et al., 2001; Simmons et al., 2008) Recent evidence that phonological processing is more closely related to mental arithmetic (DeSmedt et al, in press; Holmes & Adams, 2006)
Coexisting domain general explanations Phonological processing isnt the only or even the most influential domain general cognitive precursor of maths The role of phonological processes are however particularly important for dyslexic children
Visual memory (e. g. LeFevre et al., in press; Simmons et al., under review) Central executive processing (e. g. Bull et al., 2008; Simmons et al., under review)
Importance of mental arithmetic Central place in primary curriculum Daily oral/mental starter in the daily mathematics lesson The revised Framework places an emphasis in Key Stage 1 and the first two years of Key Stage 2 on securing children's knowledge of number facts and mental calculation strategies (Department for Children, Schools and families, n. d., p. 4).
Influence on Motivation and attitude in maths lessons Teachers perceptions of mathematical ability
Impaired number moduleBiological Cognitive Impairment intraparietal sulcus Impaired number moduleSlow and inaccurate subitising Difficulty identify quantity at a glance
BehaviouralButterworth (2005)
Severe mathematics difficulties
Assessing the number module Subitising speed Number comparison speed
4
7
Support for the role of the number module Landerl et al. (2004) Compared basic numerical skills Children with reading difficulties in the absence of severe mathematics difficulties Children with severe mathematics difficulties in the absence of reading difficulties Children with severe mathematics difficulties and reading difficulties Typically developing children
Support for the role of the number module Landerl et al. (2004) Key finding only the children with severe mathematical difficulties showed impairments on the basic tests of numerical skill Concluded that an impaired number module leads to severe mathematics difficulties dyscalculia More recent support (Landerl, Fussenegger, Moll, Willburger, 2009) The need for more longitudinal data (LeFevre et al., in press)
Defining dyscalculia 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 (DfES, 2001)
Possible subtypesPhonological processing weaknesses Impaired number module
Dyslexia with circumscribed mathematics difficulties (particularly number facts)
Dyslexia with severe mathematics difficulties. Dyslexia & Dyscalculia
Severe mathematics difficulties without dyslexia. Dyscalculia
Understanding the nature & severity of mathematics difficulties
Guide teaching & learning
Assessment
Insight in weaknesses & strengths Understanding the cognitive underpinnings of maths difficulties
May influence teaching strategy, but need for empirical evidence
Standardised tests Can be used to identify the severity of the difficulty, but performance can be influenced by type of test Written tests (e. g. BAS II, WRAT, Progress in maths) WIAT IIIUK numerical operations/reasoning breakdown Mental arithmetic (e. g. Arithmetic subscale from Wechsler Intelligence Scales)
Dyscalculia Is it possible (and useful) to distinguish dyscalculic children? Magnitude comparison tasks are suggested as a method of assessing the efficacy of the number module and therefore distinguishing dyscalculic children Consistent with DfES definition
Dyscalculia Screener Butterworth (2003) Simple reaction time press a key when you see a dot Dot enumeration (19) Number comparison Addition & multiplication verification
Subtests 89
5
3+5=8
Issues with interpretationImpaired number facts & impaired basic numerical abilities Impaired number module Domain general cognitive weakness?
Absence Impaired number facts & unimpaired basic numerical abilities Domain general cognitive weakness? Inappropriate teaching Maths anxiety
Considerations for assessment Mathematics difficulties may be subtle and circumscribed or more profound Maths assessment may therefore be appropriate even if it isnt the primary presenting problem
Considerations for assessment Tests of basic numerical abilities may be useful in identifying profound domainspecific difficulty (but bear in mind the issues with interpretation) Weak phonological processing may underpin arithmetic fact difficulties Other domain general explanations of mathematics difficulties are possible e. g. visual memory or central executive processes