Types of Dyslexia: What Researchers Are Studying and Why

By The Understood Team
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At a Glance

  • Scientists are looking into whether there are subtypes of dyslexia.

  • The goal is to understand the origin of different reading challenges.

  • There are no official diagnostic “types” of dyslexia, but finding out which aspects of reading are challenging can help people get the right support.

You may hear people talk about types of dyslexia. But what they’re really talking about are the different ways people with dyslexia can struggle with reading.

For example, some have trouble sounding out (decoding) words. Others have a hard time recognizing words by sight. Most struggle in more than one area.

There are no official types of dyslexia. But experts have been looking into possible “subtypes.” The goal of this research is to better understand the origin of different reading challenges, and eventually find better ways to treat them.

Experts think genetics plays a role. Different reading challenges may be linked to specific combinations of genes. A child’s learning experiences also affect how the brain gets organized for reading. These factors help explain why no two people with dyslexia are exactly alike.

Research into subtypes of dyslexia doesn’t mean a person has one “kind” of dyslexia or another. It’s not like being either a type 1 or type 2 diabetic.

Dyslexia subtypes are more like pieces in a puzzle. Together, they form a unique profile of what someone’s reading challenges are. These kinds of details can help schools and families find the right support to suit each student’s needs.

Experts have different ideas about how dyslexia should be broken down into subtypes. More research needs to be done in this area. But here are some of the more widely mentioned “types” of dyslexia you might hear about.

Phonological Dyslexia

This is often what people are thinking of when they talk generally about dyslexia. It’s trouble breaking down the sounds of language and matching those sounds with written symbols. Challenges with make it hard to sound out or “decode” words.

Experts think phonological dyslexia is the most common subtype. (It’s sometimes referred to as dysphonetic dyslexia.) Most people with dyslexia struggle to some degree with the sounds in words.

Surface Dyslexia

People with this subtype may be fine with sounding out new words but struggle to recognize common words by sight. It may take them longer to get to the point where they can recognize a certain word instantly without needing to sound it out.

This is probably because the brain finds it hard to remember what the word looks like. People with surface dyslexia may have particular trouble with words that don’t sound the way they’re spelled, like weight or debt, and have to be memorized.

Surface dyslexia is also called visual dyslexia or dyseidetic dyslexia. Many people have both surface and phonological dyslexia. That may be because trouble with decoding can get in the way of mastering sight words. Struggling readers might not encounter a word often enough to begin to recognize it at a glance.

Rapid Naming Deficit

Many but not all people with dyslexia have trouble rapidly naming things like letters, numbers, and colors when they see them. They can say the names, but it takes them longer to name many of them in a row. Experts think this problem is related to trouble with processing speed. They also think it’s linked to reading speed.

Double Deficit Dyslexia

A double deficit means a person with dyslexia is struggling with two aspects of reading. It’s often used to describe people who have trouble identifying the sounds in words and who have trouble with naming speed.

Many experts believe phonological dyslexia and rapid naming deficit are separate challenges, but that they can happen together. Having both of these challenges at the same time tends to add up to a more severe form of dyslexia.

Other “Types” of Dyslexia

The term visual dyslexia is used by different people in different ways. It’s sometimes used to describe surface dyslexia.

But some people use the term to mean something else. They think reading difficulties have to do with the eyes. Some claim reading can be improved through eye exercises or tinted lenses. The American Academy of Pediatrics doesn’t endorse these approaches because there isn’t enough evidence to back them up.

You may hear about other kinds of dyslexia that aren’t backed by research. For example, directional dyslexia refers to trouble telling left from right and trouble with sense of direction. Most experts agree this is a common problem for people with dyslexia. But they don’t see it as a subtype of dyslexia on its own.

You may also hear people talk about something called math dyslexia. They’re referring to a common learning difference called dyscalculia. Dyscalculia is not a form of dyslexia.

Testing for Different Reading Challenges

Researchers are still looking into what causes different types of reading challenges. But schools and clinics already have dyslexia tests that can help pinpoint which aspects of reading kids are struggling with. Watch this video to see how kids are tested for dyslexia.

Keep in mind that having dyslexia doesn’t mean people aren’t smart. It means they need more support to make progress.

Knowing which aspects of reading (like decoding or reading fluency) are challenging to a student can help schools decide how to provide the right teaching and support. See what helps students with dyslexia learn how to read, and explore ways to help at home.

See the Research

One highly cited study showed that around 80 percent of children with dyslexia had both phonological and surface dyslexia, while 20 percent had only one of the two.

Some research suggests weakness in phonological processing is separate from a naming speed deficit, and that these two challenges can happen together—as a double deficit.

Other research suggests phonological processing is connected to naming speed and that these aren’t separate subtypes.

Key Takeaways

  • Experts have different ideas about how dyslexia should be broken down into subtypes.

  • More research needs to be done in this area.

  • Understanding where reading challenges come from can help people get the right support.

About the Author

About the Author

The Understood Team 

is made up of passionate writers, editors, and community moderators. Many of them learn and think differently, or have kids who do.

Reviewed by

Reviewed by

Guinevere Eden, PhD 

is a professor at Georgetown University and director of its Center for the Study of Learning.

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