The Different Kinds of Reading Disabilities

Many students struggle to learn how to read effectively or efficiently.

Research indicates that there are three different types of reading disabilities.

These three types of disabilities relate to (if you know us…you’re probably guessing it right now!!!)

YEP…..

The Literacy Processing Triangle

Okay so let’s break this down a bit further.

Students can have a Reading Disability that is specifically related to:

1 - A phonological deficit

This means that students are struggling with the sound structure of our language. They have a difficult time breaking words into syllables, and sounds, or blending syllables and sounds to create words. They may struggle to hold onto sounds long enough to read and spell using a phonetic approach and so they rely on visual memory often guessing at words based on how the words look. This is where you may start to see spelling errors like “saw” for “was” or other full-word transpositions.

2 - An orthographic or processing speed deficit

This means that students are struggling with the visual print structure of our language. They are struggling to look at letters and quickly recognize what that letter (or letter group) is in order to pair a sound. They may struggle with letter reversals such as b/d/p/q or recognizing the difference between t, th, tch, or tion since each of those pairs with a different sound. Often students get to a point in which they can recognize the letters but they aren’t processing quickly enough to complete the literacy processing triangle loop with the speed and accuracy necessary for connected text reading.

3 - A comprehension or language deficit

This means that students are struggling with understanding what the words mean after they’ve read or heard the word. This can be a breakdown in vocabulary knowledge or in higher-order language knowledge. For example, the student may have solid concrete vocabulary but may not understand multiple-meaning words (like rock - which can be used as a noun, verb, and an adjective all with different meanings!) or they may struggle to comprehend when listening to or reading information presented in paragraphs because they struggle to identify the main idea or to make inferences/predictions with that information.

Clinically, these 3 types of reading disabilities fall into 2 categories.

Dyslexia & Reading Comprehension Disorder

In schools, these 3 types of reading disabilities fall into 1 category.

Specific Learning Disability in Reading

So let’s break this down further!

What’s Dyslexia?

Dyslexia occurs when you have a deficit in either the phonological processor or the orthographic processor (so the bottom of the literacy processing triangle). Sometimes students struggle in just one and sometimes students struggle in both the phonological and orthographic processor. When students have deficits in both the phonological and orthographic processor it’s known as the dual-deficit model and it’s important to know that students with a dual-deficit typically take longer in their reading intervention process.

What’s a Reading Comprehension Disorder?

A reading comprehension disorder often (although not always) co-occurs with a language comprehension disorder. This type of disorder can occur with or without dyslexia. If students present with deficits in all three areas of the literacy processing triangle, the intervention will take longer than it would if only one or two of the areas are impacted. A reading comprehension disorder occurs when students struggle to comprehend text even after decoding is successful. This means that even if they were able to read all the words accurately, they still would struggle to pull meaning from the text.

What’s a Specific Learning Disability in Reading?

There has been a shift away from using the term dyslexia and instead using this more global term. The reason for this shift is that researchers and clinicians began to see that there was often a great deal of overlap in each of the deficits and sometimes, depending on what data you have available you’re not able to pinpoint the cause of the reading disability. So in many cases providing a broad definition helped students to qualify for school-based or intervention services without needing to pinpoint which area within the literacy processing triangle was breaking down. The downside to this approach is that it presumes that all reading intervention should be provided the same way for any student who struggles to read. We know that this just isn’t as effective!

However, we need to make sure we’re giving schools a break - because it is not JUST schools who made this transition, the DSM-5 Diagnostic Statistical Manual put together by key medical professionals and psychologists is the most up-to-date diagnostic manual we have, and in that manual, they made this transition as well - so this isn’t a school-based issue at all. It’s not that schools don’t want to call it dyslexia necessarily, it’s just that they often don’t have the data available to pinpoint, and clinically/legally aren’t able to give that diagnostic clarification.

Hopefully, that helps a bit! Let us know in the comments!

For information on effective literacy intervention and how we can best support students who are struggling with reading, check out our FREE Science of Reading Blueprint. We believe that EVERY child has the right to effective literacy instruction, so we created this document to help bridge research-based principles and practice. Click below to learn more!