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Understanding Dyscalculia and Dyslexia: What’s the Relationship

Updated: Feb 3, 2023

Dyscalculia is a math learning disability that impairs an individual’s ability to learn number-related concepts, perform accurate math calculations, reason and problem solve, and perform other basic math skills. Research suggests that language, motor, spatial, and working memory challenges may complicate understanding of numeracy in early childhood.

Dyslexia is a specific learning disability that is neurobiological in origin. It is characterized by difficulties with accurate and/or fluent word recognition and by poor spelling and decoding abilities. These difficulties typically result from a deficit in the phonological component of language that is often unexpected in relation to other cognitive abilities and the provision of effective classroom instruction. Secondary consequences may include problems in reading comprehension and reduced reading experience that can impede the growth of vocabulary and background knowledge.

The co-occurrence of dyslexia and dyscalculia, or Specific Learning Disability in Reading and Specific Learning Disability in Math is high, yet research does not yet provide definitive clarity on the co-morbidity rate.

Co-existing dyslexia and dyscalculia are reported in clinical settings as high as 50%. Grant et. al., 2020 mention studies showing a range of from 17 to 66% of individuals with dyscalculia also fit the diagnostic criteria for dyslexia. Yet, this is an underfunded domain of research. Children with both dyslexia and dyscalculia often have difficulties in rapid automatic naming, working memory, and processing speed.

"Difficulties in arithmetic, which are obviously the hallmark of dyscalculia, are also remarkably common in dyslexia, particularly when it comes to retrieving arithmetic facts from semantic long-term memory, as is the case in multiplication (De Smedt and Boets, 2010; Göbel, 2015; Simmons and Singleton, 2008; Träff and Passolunghi, 2015). A possible explanation for this finding is that arithmetic fact retrieval might be influenced by phonological processes (De Smedt et al., 2010; Dehaene et al., 2003; Geary and Hoard, 2001)," Peters et al., 2018.

Did You Know?

  1. 50% to 60% of children with dyscalculia also have dyslexia

  2. Up to 50% of 7th graders do not know their math facts

  3. 75% of people with ADHD have at least one additional diagnosis, often dyslexia and or dyscalculia

A Brief Overview of Dyslexia Stacy Fretheim, MS, CCC-SLP

Understanding Dyslexia requires an understanding of the differences between Phonemic Awareness and Phonics

Phonemic Awareness is perceiving, understanding, and replicating the sounds in spoken language. Phonemic Awareness is the awareness of the smallest parts of sound in a spoken word and the understanding that words are made up of speech sounds (or phonemes). Phonemic Awareness is all about the ability to distinguish and then manipulate these individual speech sounds in spoken words.

Phonics is mapping those sounds to representational (orthographic) images we call letters. Phonics is a way of teaching children how to read and write. It helps children hear, identify and use different sounds that distinguish one word from another in the English language.

Written language can be compared to a code, so knowing the sounds of individual letters and how those letters sound when they’re combined will help children decode words as they read (National Literacy Trust).

Phonemic or phoneme awareness is a more specific language-sound consciousness inside the larger skill of phonological awareness. Phoneme awareness encompasses the ability to perceive the smaller sound segments of spoken words and to be aware of the differences between these phonemes, which can be manipulated and substituted to form different words.

  • The most distinguishing feature of dyslexia is poor phonological awareness, which manifests in an inability to identify and blend together individual phonemes in words.

  • Individuals who have difficulties in phonemic awareness may have difficulties producing rhymes and recognizing words that rhyme, counting phonemes in a word (segmenting), deleting, adding, or moving sounds around in a word (elision), and hearing sounds in isolation and blending them together to form a word (blending).

  • The lack of phonemic awareness had been found to be a high predictor of a reading disability.

  • The systematic teaching of phonemic awareness is critical for individuals diagnosed with dyslexia.

Sensory Motor Skills, Coordination, Motor Timing, and Executive Functions are also Important in Dyslexia and Dyscalculia - These are neurodevelopmental disorders that are biological in origin

Science shows us that associated deficits in language, executive function, and motor skills, play an important role in the expression of dyslexia and dyscalculia.

Associated symptoms in co-existing dyscalculia and dyslexia to look for:

  • Attention deficits

  • Difficulty recognizing patterns

  • Difficulty understanding sequences have a beginning, middle, and end

  • Difficulty with the rapid naming of objects, letters, or numbers

  • A preference not to read or compute age-appropriate math problems out loud

  • Slow verbal processing of syllable sounds and number relationships

  • Diminished motor tempo and timing

  • The presence of fine or gross motor deficits

  • Difficulty forming visual images in one's mind of language or numeracy

  • Difficulty with planning and task execution, using a trial and error planning process, that varies from moment to moment

"We see dyslexia as an interplay of neurodevelopmental uniquenesses not simply as a "reading disorder" this helps us best treat related underlying brain differences in language, sensorimotor, and executive function while maximizing associated strengths and abilities."

How I Met Dyscalculia

As a pediatric psychologist and mother of two, volunteering in a local PVUSD school in 2009, I met many bright students in grades 3-6 for whom math was a mystery. These students would memorize math facts one day and forget them the next. They would confuse addition and multiplication. Memorizing math facts felt like a foreign language. The students had a limited understanding of currency, decimals, and simple fractions and they were frustrated. As a researcher, educator, and mom, I studied the research. What I learned was motivating and inspiring.

What is Dyscalculia?

Dyscalculia is a neurobiological condition that affects the ability to acquire arithmetic skills. Dyscalculia is identified in the DSM-V as a specific learning disability that affects a child’s ability to understand, learn, and perform math and number-based operations.  Children with dyscalculia may have difficulty understanding simple number concepts, lack an intuitive grasp of numbers, and have problems learning number facts and procedures, (DfES, 2001).

  1. Though research on prevalence is limited, it’s estimated that between 5 and 7% of elementary school-aged children may have dyscalculia. It’s also currently thought that dyscalculia occurs equally in both genders, trending slightly higher in females (

  2. According to National Center for Learning Disabilities, dyscalculia is a lifelong disorder that can be ameliorated with direct and systematic interventions.

  3. The effects of dyscalculia vary from individual to individual therefore, a comprehensive evaluation may be needed for an accurate diagnosis.

  4. Treatment protocols are individualized as a child who presents with difficulties in processing language may have a different presentation when compared with a child who has difficulties in spatial relationships (NCLD, 2006).

  5. Dyscalculia is not accounted for by uncorrected visual or auditory acuity, other mental or neurological disorders, psychosocial adversity, lack of proficiency in the language of academic instruction, or inadequate educational instruction.

Typical Features of Dyscalculia – Haberstroh & Schulte-Körne (2019)

Difficulties in processing numbers and quantities, starting in the preschool years

  • The connection between a number (e.g., 2) and the quantity it represents (e.g., 2 apples) is made only with difficulty.

  • The relation between numbers and quantities (two apples and one apple = 2 + 1) is inadequately understood.

  • Ensuing difficulties in counting, comparing two numbers or quantities, rapid assessment, and naming of small quantities of dots, determining the position of a number on the number line, understanding the place-value system, and transcoding.

Difficulties with basic arithmetic operations and with further mathematical tasks

  • Computation rules are not understood because the underlying comprehension of numbers and quantities is lacking or insufficiently developed.

  • Deficits in the retrieval of math facts (e.g., the multiplication table) with which the answers to simple calculation problems can be recalled directly from memory, rather than needing to be calculated anew each time.

  • Lack of transition from computation by counting by ones to non-counting strategies.

  • These difficulties become worse with increasing mathematical complexity (larger number range, written computations, multiple calculating operations, word problems).

Students with Dyscalculia have difficulty understanding and holding onto quantity, sequencing, and number relationships.

It is important when one is administering a comprehensive evaluation of dyslexia that they include at least a screener for dyscalculia, a condition that exists at approximately the rate of dyslexia, yet goes undiagnosed.

Additional Screeners Dyscalculia.Org

Related Post:

More resources…

Grant, J. G., Siegel, L. S., & D'Angiulli, A. (2020). From Schools to Scans: A Neuroeducational Approach to Comorbid Math and Reading Disabilities. Frontiers in public health, 8, 469.

Peters, L., Bulthé, J., Daniels, N., Op de Beeck, H., & De Smedt, B. (2018). Dyscalculia and dyslexia: Different behavioral, yet similar brain activity profiles during arithmetic. NeuroImage. Clinical, 18, 663–674.

Peters, L., Op de Beeck, H., & De Smedt, B. (2020). Cognitive correlates of dyslexia, dyscalculia and comorbid dyslexia/dyscalculia: Effects of numerical magnitude processing and phonological processing. Research in developmental disabilities, 107, 103806.

Willcutt, E. G., Petrill, S. A., Wu, S., Boada, R., Defries, J. C., Olson, R. K., & Pennington, B. F. (2013). Comorbidity between reading disability and math disability: concurrent psychopathology, functional impairment, and neuropsychological functioning. Journal of learning disabilities, 46(6), 500–516.

Willburger, E., Fussenegger, B., Moll, K., Wood, G., & Landerl, K. (2008). Naming speed in dyslexia and dyscalculia. Learning and Individual Differences, 18(2), 224–236.

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