Dyslexia, Dysgraphia, Dyscalculia & Developmental Language Disorders
Students who are assessed to determine the cause of their reading struggles are often given a general diagnosis of “Specific Reading Disability.” This diagnosis, while using the word specific, is unhelpfully unspecific. Differentiating between precise diagnoses provides guidance on the types of strategies that best fit a particular type of struggle.
Diagnostic Terms:
There are three truly specific diagnostic terms for problems that lead to weak reading and writing skills:
- Dyslexia - a disorder impacting the ability to efficiently and effectively obtain word-level and subword-level skills for reading (such as establishing automatic sound-to-letter connections, “sight word” skills and reading fluency)
- Dysgraphia - a disorder impacting the ability to efficiently and effectively obtain word-level and subword-level skills for writing (such as establishing handwriting skills of letter orientation, word spacing, legibility, and speed)
- Developmental Language Disorder (DLD) - a disorder impacting the oral language system, primarily impeding verbal expression & listening comprehension (such as vocabulary development, higher level grammar skills, and inferential understanding)
There can also be any combination of these three. When two or more disorders exist together, this is referred to as “comorbidity:” students can have both dyslexia and dysgraphia or dyslexia and DLD.
Students with dyslexia may also experience a weakness in math, and may be diagnosed with:
- Dyscalculia - a disorder impacting the ability to efficiently and effectively obtain word-level (labeling skills) and symbol-level skills (numbers) for writing in math. Like dysgraphia, students struggle with writing numerals with proper orientation, spacing, size, legibility, and speed.
Each of these diagnostic terms comes with a cluster of symptoms, which will be further explained below. Download a comprehensive list of indicators here.
Don't "Dys" Labels:
Before we explain these symptoms, let’s discuss the concept of “labels.” Let’s be very clear: labels don’t define a child. They define a child’s struggle. Labels help us understand our kids and find answers to our questions.
Labels are tools. When we have children who struggle with learning, a diagnosis helps us find resources and make connections. Most importantly, it helps us approach learning using appropriate strategies with proven effective outcomes.
A diagnosis also creates a cycle of understanding: the better we define a cluster of learning struggles, the more researchers begin to identify neurocognitive connections, the more educators explore strategies for improvement. As this cycle continues, information about various treatment options—and their efficacy—is made available. Resources grow.
In other words—and this is the goal—the better we are able to differentiate between types of learning struggles, by diagnosing and solidifying our understanding, the better our intervention.
Dyslexia:
Dyslexia is also from a Greek base word lex, which means word. It involves impairment in word-level reading and spelling skills. Professionals are developing better assessments for dyslexia, and fortunately, it is more accurately diagnosed. Mild dyslexia is often overlooked.
Children with dyslexia have difficulty with:
- word level skills—accurately reading and spelling words
- reading fluency—easily recognizing words for reading speed
- reading comprehension—comprehending as well as when listening to text
In summary, dyslexia is a language-based reading disorder that:
- leads to cognitive fatigue while reading
- drains working memory resources
- interferes with reading comprehension
- involves difficulty in spelling accurately and easily
- interferes with written composition
- may occur without additional difficulty in handwriting (dysgraphia)
- may occur with additional word retrieval and letter naming weakness
Dysgraphia:
Dysgraphia is perhaps the most debated and confusing label. It is also poorly diagnosed with few assessment tools available. Unfortunately dysgraphia continues to be defined and treated primarily as a fine motor disorder, despite research to the contrary. The word dysgraphia is from the Greek base word graph, which means letter. Dysgraphia is an impairment in letter formation.
Children with dysgraphia have difficulty with:
- subword letter formation—producing legible letters others can recognize
- [writing] automatically and consistently
In summary, dysgraphia is a written language disorder that:
- leads to cognitive fatigue
- drains working memory resources
- interferes with writing letters properly and easily
- involves difficulty in retrieving and producing letters at will
- interferes with spelling and written composition
- may occur without additional difficulty in reading (dyslexia).
Dyscalculia:
Dyscalculia is often overlooked, and research is fairly new in understanding the possible co-occurrence of dyscalculia and dysgraphia. Based on another Greek base word, dyscalculia is an impairment in calculation. Children with dyscalculia may not be impaired in their comprehension of all quantitative skills, but like dysgraphia and dyslexia, it is a disorder at the sub-word level.
Children with dyscalculia have difficulty with:
- fast mapping and automaticity of symbols—in this case, math symbols
- difficulty recalling all related number labels and their variations based on placement—such as one, eleven, one hundred, one thousand, one million, etc.
In summary, dyscalculia is a language-based math disorder that:
- leads to cognitive fatigue
- drains working memory resources
- interferes with computational procedures such as addition, subtraction, multiplication, and division
- involves difficulty in writing and labeling numbers
- interferes with written composition of math problems
- usually cooccurs with dyslexia
- occurs with additional difficulty in handwriting (dysgraphia)
Developmental Language Disorder:
Developmental Language Disorder (DLD) is now the preferred term for inconsistent terms for language problems, also called: Expressive & Receptive Language Disorder, Specific Language Disorder, Language Learning Disorder or Oral Written Language Learning Disability. This learning struggle involves global language skills, so it becomes evident in the early toddler and preschool years as children struggle to progress in both their verbal and listening language development.
Characteristics of an DLD include children who:
- are late talkers
- struggle with listening comprehension
- struggle to express ideas and formulate thoughts
- have weak syntax (grammar) skills in early language
- present with weak vocabulary development
- struggle to comprehend inferential information
Once these children are reading and writing, they will:
- have weak reading comprehension skills
- struggle with writing composition
- demonstrate weak grammar skills
- demonstrate weak vocabulary skills
Some children with DLD may have co-occurring speech delays. In addition, some will demonstrate dysgraphia and/or dyslexia once they begin literacy instruction.
Knowledge prevents “Dysteachia”:
When we have children who struggle with learning, a diagnosis helps us find resources and make connections. Most importantly, it helps us approach learning using appropriate strategies with proven effective outcomes.
In other words—and this is the goal—the better we are able to differentiate between types of learning struggles, by assessing and solidifying our understanding, the better our intervention. When we identify our student’s struggle and strengthen the skills they need, the better their progress. Hope grows.
Labels do not define who a child is, but they can give us a better sense of what a child is living with in their educational life. Better understanding leads us to better support.
Citations:
“Developmental Outcomes for Children at High Risk of Dyslexia and Children With Developmental Language Disorder” by Snowling et al., 2019.
“Dyslexia and Developmental Language Disorder: Comorbid Disorders with Distinct Effects on Reading Comprehension” by Snowling et al., 2020.
Dyslexia, Dysgraphia, OWL LD, and Dyscalculia: Lessons from Science and Teaching, by Virginia Berninger and Beverly Wolf, 2016.
“Language and Reading Comprehension: Linking Science to Promising Practice” by Hogan, 2023.
“Reframe Your Thinking About SLP Roles, Assessment, and Treatment of Dyslexia and Related Disorders” by Nelson, 2022.
"Revisiting the Definition of Dyslexia" by Catts et al., 2024.
Subgrouping Poor Readers on the Basis of Individual Differences in Reading-Related Abilities” by Catts, Hogan, & Fey, 2003.
"Towards a Dynamic, Comprehensive Conceptualization of Dyslexia" by Wolf et al., 2024.
