Dyscalculia

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Dyscalculia

• Stephen Albone

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A learning disability refers to a retardation,
disorder, or delayed development in one or more
of the processes of speech, language, reading,
writing, arithmetic, or other school subject
resulting from a psychological handicap caused by
a possible cerebral dysfunction and/or emotional
or behavioral disturbances. It is not the result
of mental retardation, sensory deprivation, or
cultural and instructional factors. Samuel
Kirk (1962) Educating Exceptional Children, p.263.
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Developmental dyscalculia is a structural
disorder of mathematical abilities which has its
origin in a genetic or congenital disorder of
those parts of the brain that are the direct
anatomico-physiological substrate of the
maturation of the mathematical abilities adequate
to age, without a simultaneous disorder of
general mental functions. Ladislav Kosc
(1970) Studia Psychologica, vol 12, pp 159-162.
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Developmental dyscalculia is a disorder in
mathematical abilities presumed to be due to a
specific impairment in brain function.
Wilson Dehaene (2007) In Human Behavior,
Learning and the Developing Brain Atypical
Development, Guildford Press, New York.
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Modelling Learning Disabilities
OperationalDefinitions
Developmental Perspectives
Behaviour
Physiological Factors
Environmental Factors
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Dyscalculia Checklist

• Use of calculation strategies typically used by
  younger children, but prone to error.
• Slow at counting and calculating.
• Difficulty in retrieving number facts.
• Do not know their tables.
• Poor at monitoring their counting and detecting
  computational errors.
• Problems switching between different strategies
  when completing mathematical problems.
• Margaret Snowling (2005) Psychiatry, vol 4, pp
  110-113.

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• Developmental
• Perspectives

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Learning to Count

• Stable order principle
• One-to-one principle
• Cardinal word principle
• Order irrelevance principle
• Abstractness principle

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The Development of Arithmetic

• Counting all
• Counting on from first
• Counting on from larger
• Recall

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The Role of Memory

• Working Long-Term Memory
• Memorising Number Facts
• How It Goes Wrong The Link With Other Special
  Educational Needs.

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Behavioural Model of Arithmetic Achievement
Accuracy
High
Developmental Delay
High Arithmetical Ability
Low
Learning Disability (Dyscalculia?)
Impulsive/ Guesser
Slow
Fast
Response Time
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• Physiological
• Perspectives

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Magnitude Representations
Verbal Representations
Visual/Spatial Representations
Dehaene et al. (2003) Cognitive Neuropsychology,
vol. 20, pp. 487-506.
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• Theories of
• Dyscalculia

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The Defective Number Module Hypothesis

• Proposed by Brian Butterworth
• Arithmetic development is dependent on the
  ability to subitise.
• This is the innate ability to understand and
  manipulate small whole number quantities.
• Butterworth calls this ability numerosity.
• If this is defective the results are catastrophic
  for arithmetical development.

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The Core DeficitHypothesis

• Proposed by Stanislas Dehaene colleagues.
• The deficit lies with the failure of the brain
  region concerned with magnitude recognition.
• Deheane calls this ability Number Sense.
• This interacts with our verbal systems to give
  additional semantic information about numbers.
• Effectively this allows us to understand
  arithmetic.
• Remediation involves rote learning techniques.

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ConcludingRemarks

• There are many reasons why children experience
  difficulties with mathematics.
• The term dyscalculia should be reserved for a
  particular type of specific learning disability.
• At the present time dyscalculia remains a
  hypothetical condition.

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