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Dyscalculia Explained

By Anna Witkin, Medical Consultant |
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Dyscalculia Definition

Dyscalculia is a learning difference in math that, like most learning differences, is conceptualized in two different ways. Under the discrepancy model (traditionally used by psychology professionals), dyscalculia is a term used to describe a weakness in math relative to an individual’s overall cognitive abilities. Many educational systems employ the absolute model of learning differences, which will consider students to have dyscalculia if they consistently perform below grade level in math, regardless of their capabilities in other academic subjects.

It should be noted that while dyscalculia is not defined in either of the primary classification systems used in psychology (the DSM-5 and ICD-11), there is considerable overlap between dyscalculia and a Specific Learning Disability (SLD) in math as defined by the DSM-5. Because these terms are sometimes used interchangeably, the DSM-5 criteria for SLD in math will be outlined below.  

What Is Dyscalculia?

Dyscalculia has been estimated to affect between 3-6% of school-aged children, but diagnostic ambiguity makes it difficult to ascertain the true prevalence (Auerbach et al., 2001, p. S58). While studies suggest dyslexia and dyscalculia may be equally common, there is much less awareness of, and research devoted to dyscalculia. This may be in part because for many people, strong math skills are not required after high school, whereas reading impairments can continue to impact day-to-day life through adulthood.

The DSM-5 does not define the term dyscalculia but defines an SLD in mathematics as an impediment to the ability to learn math due to some combination of difficulty with arithmetic memorization, number sense, fluency of calculations, and capacity for math reasoning.

To meet criteria for this SLD, the impairment must be sufficient to cause the student to perform significantly behind their grade level in math for at least 6 months and persist even after receiving targeted help. These difficulties must not be better explained by lack of proper instruction, other developmental disability, or other neurologic or sensory deficits.

Dyscalculia Symptoms

Children with dyscalculia in preschool and kindergarten may struggle to learn to count, rely heavily on counting on their fingers, or have trouble recognizing numbers. School-aged kids may be very slow with arithmetic, have trouble manipulating numbers to solve problems, have difficulty keeping score in games, or be unable to calculate change in monetary transactions. In adulthood it is often possible to avoid having to solve more complex math problems, and calculators can obviate the need for mental arithmetic. While this tends to make dyscalculia less problematic later in life, individuals may still struggle with managing their money. 

It must be emphasized that although the above symptoms are quite common in individuals with dyscalculia, many of them are also common in the general population. Furthermore, formal diagnoses are not made based on the subjective experience of struggling with math. The primary utility in recognizing these symptoms is prompting appropriate formal testing.

Dyscalculia Testing

One of the most important features of an accurate diagnosis of dyscalculia is synthesis of the individual’s overall academic capabilities across different domains and throughout time. Because there is so much potential for confounding factors influencing an individual’s academic performance in math, as much data should be obtained from as many different sources as possible. These sources should likely include the student themselves, parents, teachers, and neuropsychological testing. Another important factor to consider is the presence or absence of a marked discrepancy between performance in other subjects and in math. Strong students performing well below their baseline in one subject may be especially likely to benefit from targeted interventions.

It should be noted that given the lack of understanding of the underlying neurologic processes and the many combinations of factors that produce the same result (a poor academic performance in math), it is difficult to ensure an accurate diagnosis of dyscalculia.

Learning math is much more dependent on teaching quality than learning reading, making the diagnosis of dyscalculia more difficult than that of dyslexia. Furthermore, because math concepts build upon each other, inadequate instruction in early math classes can result in ongoing struggles. A student with a good math teacher in 4th grade could struggle if they had a bad teacher in 1st and 2nd grade as they may never have mastered the basics. It can thus be especially difficult to untangle what is attributable to the student and what to the teacher in the case of poor math performance.

What Happens After Diagnosis?

After an individual is diagnosed with dyscalculia, they will generally be offered accommodations such as extra time on exams or assignments. They may also benefit from more individual instruction. Because each student with dyscalculia may struggle most with different aspects of learning math, there is no one teaching strategy that will be most effective for everyone. Successful interventions may require some trial and error and ongoing communication with the learner.

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Anna Witkin, Medical Consultant

Anna Witkin is a contributing writer for Polygon. Anna holds a BA from UC Berkeley, a Masters in Biomedical Science from Tufts, and researched ADHD, dyslexia, and other learning differences during her time at Dartmouth School of Medicine studying for her MD.

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