Learning Skill Disorders DYSLEXIAS DYSGRAPHIAS DYSORTHOGRAPHIAS DISORDERS IN THE ARITHMETICAL AND NUMERICAL SKILLS DYSCALCULIAS

Calculation disturbances Among the Learning Skill Disturbances, calculation disturbances, even if extremely important and widespread, are less studied and known than other disorders. That is why rehabilitation plans are scarce and not so valid.

Cut-off In the continuum going from exceptional to scarce performances, the cut-off between “normality” and“pathology” is represented by a score to a specific standard test which is at least two standard deviations (- 2 SD) below the expected level, based on the age and general intelligence of the child.

Exclusion Criterion Even for Dyscalculia, the exclusion criterion is the presence of a mental retard (IQ less than 70). For diagnostic purposes, the following assessments must be carried out: Neurological Neuropsychological ( general cognitive, linguistic and video-spacial skills ) Attention and memory Psychological (self-evaluation, motivation, personality).

Statistical distribution and cut-off

Prevalence (= essential knowledge) As for the datum of prevalence, the calculation disorder affects in an isolated way 3% of the school population It is associated to reading and writing disorders in 2,5 to 3% of cases

Dyscalculias Classification Inability in number reading and writing if lexical mistakes are present DYSLEXIA FOR DIGITS Difficulties in acquiring procedures and calculation algorythms with mistakes in putting in columns, amounts carried over and borrows … PROCEDURAL DYSLEXIA Difficulties in memorizing multiplication tables, numeric sequences, mental calculation, etc. DYSCALCULIA FOR ARITHMETIC FACTS

Incidence of the dyscalculic disorder From a research dating back to 1996 carried out on 3029 people aged between 10 and 11, the incidence was: Dyscalculic people : 6,1% Dyslexic people: 6,5% Only Dyscalculic people : 5,4% R. Shalev et al. (1996)

Evolution between the age of 8 and 11 According to data emerged in a recent research carried out on Italian children, with the passing age and the development of the required performance, one can observe an increase in the percentage: NUMERICAL SKILLS From 1% to about 6% UNDERSTANDING AND THINKING SKILLS From 8 to 14%

Skills deficit  Understanding specific words, operations and mathematical concepts Applying the symbolic reasoning to problems Organizing objects according to common characteristics

Skills Deficit Recognizing mathematical symbols  Copying numbers correctly  Respecting the operations  Counting objects carefully  Learning the multiplication tables by heart  Following a sequence of mathematical steps

PROCESSING SUBSYSTEMS Understanding the number system Understanding the calculation system Understanding the production of numbers system

1. Understanding the number system - Semantics It regulates the understanding of quantity Verbal code /wʌn/ Arabic code 1

1. Understanding the number system - Semantics Verbal code /θriː/ Arabic code 3

1. Understanding the number system - Lexicon It regulates the name of the number Arabic code 1 /wʌn/

1. Understanding the number system - Lexicon Arabic code 11 /ɪˈlevn/

1. Understanding of the number system - Syntax It regulates the inner number grammar, that is place value of digits. The position occupied in space modifies the name e the value. /tuː/ 2

1. Understanding the number system - Syntax /ˈtwentɪ/ 20

2. Understanding the calculation system It includes: processing operation signs (+ = sum; - = difference; x = product; / = division; ecc.) Activation of number facts (mnemonic calculation procedure (multiplication tables) mental calculation skills) Calculation procedure (algorythms, amounts carried over, ecc.)

3. Understanding the production of numbers system It represents the output of the system of calculation, and, this way, it gives the numerical answers thanks to an elaboration skill