Dyscalculia is defined as an impairment of basic arithmetic skills (addition, subtraction, multiplication, division), which cannot solely be explained by a general intelligence deficit nor by inadequate learning environment (ICD-10: Dilling et al., 1993).
In the ICD-11, (developmental) dyscalculia is described as a developmental learning disorder that is characterized by a lack of “skills related to mathematics or arithmetic, such as number sense, memorization of number facts, accurate calculation, fluent calculation, and accurate mathematic reasoning” (World Health Organization, 2020).
Dyscalculia is a Specific Learning Disability now known to affect around 6% of the population. Dyscalculia is highly comorbid with both Dyslexia and ADHD but Dyscalculia is a separate disorder that should be treated accordingly.
Research shows that indicators for developing Dyscalculia can already be detected in 5-6-month-old babies. The researchers discovered that they are attentive towards “numerosities” – in other words, core systems. This is an important discovery not least because these inborn core mechanisms enable fast-track learning. If this core system is not functioning properly, it can be seen long before children enter school.
Doing arithmetic requires a highly specified neuro-cognitive network. The starting point for the development of this network is an early core mechanism. Dyscalculia results when this core mechanism is deficient. Karin Landerl, 2010: Dyscalculia – the Neglected Learning Disability. University of Tuebingen, Germany.
Different people have a range of mathematical abilities – some people have minor problems and react well to being taught in a different way, while other children and adults have more serious problems. Partly these differences seem to stem from the ability to concentrate, so they may be influenced by coexisting conditions – Two Dyscalculia Subtypes With Similar, Low Comorbidity Profiles: A Mixture Model Analysis (2021).
Dyscalculia can include
- Math concepts, numbers, and reasoning.
- Remembering math facts.
- Executing maths procedures.
- Solving mental math.
- Reading clocks to tell time, and time awareness.
- Calendars, schedules and dates, planning and organisation.
- Counting money.
- Identifying patterns.
- Sequences – like phone numbers, addresses, passwords, codes, directions and maps (left and right, up and down, navigating).
- Visual-spatial memory.
For example, mental number line tasks, which require participants to locate a given number on a number line, or the ability to convert auditorily presented numbers into written Arabic symbols (transcoding; Nuerk et al., 2006; Kuhn et al., 2013, 2017).