Dyscalculia is usually perceived of as a specific learning difficulty for mathematics, or, more appropriately, arithmetic.
Currently (January 2015) a search for ‘dyscalculia’ on the Department for Education’s website gives 0 results as compared to 44 for dyslexia, so the definition below comes from the American Psychiatric Association (2013):
Developmental Dyscalculia (DD) is a specific learning disorder that is characterised by impairments in learning basic arithmetic facts, processing numerical magnitude and performing accurate and fluent calculations. These difficulties must be quantifiably below what is expected for an individual’s chronological age, and must not be caused by poor educational or daily activities or by intellectual impairments.
Because definitions and diagnoses of dyscalculia are in their infancy and sometimes contradictory, it is difficult to suggest a prevalence, but research suggests it is around 5%. However, ‘mathematical learning difficulties’ are certainly not in their infancy and are very prevalent and often devastating in their impact on schooling, further and higher education and jobs. Prevalence in the UK is at least 25%.
Developmental Dyscalculia often occurs in association with other developmental disorders such as dyslexia or ADHD/ADD. Co-occurrence of learning disorders appears to be the rule rather than the exception. Co-occurrence is generally assumed to be a consequence of risk factors that are shared between disorders, for example, working memory. However, it should not be assumed that all dyslexics have problems with mathematics, although the percentage may be very high, or that all dyscalculics have problems with reading and writing. This latter rate of co-occurrence may well be a much lower percentage.
Typical symptoms of dyscalculia/mathematical learning difficulties
Has difficulty when counting backwards.
Has a poor sense of number and estimation.
Has difficulty in remembering ‘basic’ facts, despite many hours of practice/rote learning.
Has no strategies to compensate for lack of recall, other than to use counting.
Has difficulty in understanding place value and the role of zero in the Arabic/Hindu number system.
Has no sense of whether any answers that are obtained are right or nearly right.
Tends to be slower to perform calculations. (Therefore give less examples, rather than more time).
Forgets mathematical procedures, especially as they become more complex, for example ‘long’ division.
Addition is often the default operation. The other operations are usually very poorly executed (or avoided altogether).
Avoids tasks that are perceived as difficult and likely to result in a wrong answer.
Weak mental arithmetic skills.
High levels of mathematics anxiety.
Because mathematics is very developmental, any insecurity or uncertainty in early topics will impact on later topics, hence to need to take intervention back to basics.