Types of Dyslexia - Explained
- Arcadia Literacy
- Mar 9, 2018
- 6 min read
Updated: Mar 6
types of Dyslexia
Reading and spelling might seem like simple tasks, but they actually rely on a whole team of brain skills working together! For kids with dyslexia, though, these brain skills don’t always sync up as they should, making it trickier to recognize and make sense of written words. Dyslexia is often thought of as a single condition, but experts have started to realize it’s more like a collection of different challenges. Each one links to a specific area of the brain, and understanding these differences helps educators and reading specialists get to the heart of the issue faster, leading to better and more lasting results.
Even though there isn’t an official list of dyslexia types, researchers have noticed certain patterns in how different kids struggle with reading. From having a hard time decoding words to trouble recognizing familiar sight words, or even processing information at a slower pace—there are various ways dyslexia can show up. Let’s dive into some of the most common types of dyslexia and see how they each make reading a bit more tricky for kids!
Understanding the Cause of Dyslexia Types
The dual route model of reading helps explain how we process written language through two different pathways: the phonological route (sublexical) and the orthographic route (lexical). The phonological route is all about sounding out words, relying on the ability to decode letters and sounds. The lexical route, on the other hand, is used for recognizing whole words by sight, without needing to sound them out. In the context of dyslexia, the dual route model shows how different types of dyslexia can arise depending on which route is affected. For example, children with phonological dyslexia have difficulty using the phonological route to sound out words, while those with surface dyslexia struggle with the lexical route, making it harder to recognize sight words. Understanding this model helps reading specialists target the right intervention for the specific pathway that’s causing difficulty, allowing for more personalized and effective treatment.
This graph demonstrates the impact of these core skills on dyslexia typing. Using the dual route model of reading, we can see a clear devide amongst student's based on their development of each skill. A child with well a developed memory for letters and words (orthographic processing) and a deficiency in their phonological processing may have phonological dyslexia.
Phonological Dyslexia
Phonological dyslexia is often what people think of when they hear the term "dyslexia." It is the most common form and primarily impacts a child’s ability to process the sounds of language (phonemes) and match those sounds with their written symbols (letters). This makes phonological dyslexia particularly challenging when it comes to decoding words (sounding them out) and spelling.
Signs and Symptoms:
Difficulty breaking down words into individual sounds or blending sounds together.
Trouble with letter reversals, such as confusing “b” and “d.”
Struggles with adding, dropping, or substituting sounds in words.
Difficulty recognizing rhyming patterns.
Example: A child with phonological dyslexia might spell “was” as “saw” or “party” as “pawdy,” swapping sounds or letters because they cannot process the sounds in the word properly. They might also skip words or misread them during fluent reading.
In addition to struggling with spelling and decoding, children with phonological dyslexia may also have challenges with phonemic awareness activities, such as identifying words that rhyme or segmenting words into their individual sounds.
Surface Dyslexia (Orthographic)
Surface dyslexia, also known as orthographic dyslexia, affects a child’s ability to retain visual representations of words and recognize them by sight. While children with phonological dyslexia might struggle with decoding words, children with surface dyslexia have difficulty remembering and identifying familiar words that don’t follow typical phonetic rules.
Signs and Symptoms:
Difficulty remembering sight words or irregularly spelled words, such as “though,” “was,” or “said.”
Trouble recognizing word patterns.
Spelling irregular words incorrectly (for example, spelling “weight” as “wate” or “their” as “thar”).
Difficulty learning how to spell sight words by memory, especially those that don’t align with phonetic rules.
Example: A child with surface dyslexia might see the word “could” and try to sound it out phonetically, resulting in incorrect readings such as “cud.” Over time, they may begin to confuse similar-looking words or fail to recognize them altogether when they encounter them in texts.
Surface dyslexia often impacts a child's ability to spell words that don't follow standard spelling rules, such as those that include silent letters or unusual letter combinations. This is because these words are often learned through memorization, and surface dyslexia impairs this ability.
Dual Deficit Dyslexia
As the name suggests, dual-deficit dyslexia involves a combination of both phonological and surface dyslexia. Children with dual-deficit dyslexia struggle with both decoding and word recognition, making reading and spelling even more challenging.
Signs and Symptoms:
Difficulty both with phonological processing (decoding) and visual word recognition (sight word recall).
Severe issues with spelling both regular and irregular words.
Slower reading fluency due to the combination of challenges in both areas.
Poor performance on word retrieval tasks.
Example: A child with dual-deficit dyslexia might struggle with sounding out words like “tap” and “cat,” but they may also struggle with recognizing sight words like “was” or “could,” even after seeing them multiple times. They may need additional support to address both areas of difficulty simultaneously.
Children with dual-deficit dyslexia often experience the most severe reading challenges. Because they struggle with both phonemic awareness and sight word recognition, their reading fluency and comprehension are significantly impacted.
Stealth Dyslexia
Stealth dyslexia refers to a more subtle form of dyslexia that may go undiagnosed for years. Unlike the more obvious types of dyslexia, stealth dyslexia may not immediately present with severe reading and spelling difficulties. Instead, these children may appear to perform well in school, but their reading difficulties become evident over time as academic expectations increase. It is most common in gifted children who score within the average range for reading skills, but are considered behind when contrasted against their reading potential.
Signs and Symptoms:
Slow reading progress that becomes more apparent as the child gets older and is expected to read more complex texts.
Difficulty with spelling irregular words and sight words, even though they can sound out simple words.
Poor reading comprehension because the child may struggle to decode more complex words or remember their spelling.
Often mistaken for a child who is simply a "slow learner" or has ADHD.
Example: A child with stealth dyslexia may be able to read short words and decode them properly but struggle to recognize or spell words like “though” or “their.” Over time, as reading becomes more challenging in school, their struggles become more apparent.
Stealth dyslexia often goes unnoticed because children with this type may mask their difficulties by relying on memorization or compensatory strategies. However, as academic demands increase, their reading challenges begin to show, leading to frustration and a decline in performance.
The Impact of Rapid Naming Deficit (RAN) and ADHD on Dyslexia
Two other factors that can significantly impact a child’s experience with dyslexia are Rapid Automatized Naming (RAN) deficits and Attention Deficit Hyperactivity Disorder (ADHD).
Rapid Naming Deficit (RAN):
RAN refers to a child’s difficulty in quickly naming or recognizing letters, numbers, or colors in a rapid sequence. This difficulty is often linked to slower processing speeds and affects reading fluency, as well as word retrieval.
Children with RAN deficits might read slowly and inconsistently. Some days they may appear to read well, while other days they may struggle significantly, especially when they need to retrieve words quickly.
They often demonstrate high accuracy after reading intervention, but may continue to struggle with reading rate as a result of low RAN.
ADHD:
Children with ADHD often experience difficulties with attention, focus, and impulse control. These challenges can further complicate the symptoms of dyslexia, particularly when it comes to following multi-step instructions, staying on task during reading activities, and remembering key concepts.
A child with both ADHD and dyslexia may struggle to stay focused while reading and may have difficulty retaining the information they read, which can exacerbate their challenges.
ADHD can frequently present as Orthographic dyslexia because of the difficulties with attention to symbols and challenges with working memory.
Both RAN and ADHD can compound the difficulties associated with dyslexia, making it even more important for educators to recognize and differentiate these factors during assessments.
Dyslexia is a complex and multifaceted disorder, often stemming from a combination of different cognitive challenges. While there are no official classifications, recognizing the distinct types of dyslexia—phonological, surface, dual-deficit, and stealth—can help specialists tailor their interventions. Understanding the impact of factors like RAN deficits and ADHD can further guide treatment plans, ensuring that children receive the most effective support for their unique needs.
Early diagnosis and a comprehensive evaluation are key in helping children with dyslexia overcome their challenges. When a child’s specific subtype is identified, reading specialists can implement targeted strategies that address the root causes of their struggles, leading to improved outcomes in reading and writing skills.
