There are two different types of dyslexia: developmental and acquired. The condition is further subcategorized based on symptoms, such as trouble breaking words down into individual sounds or difficulty recognizing familiar printed words.
Dyslexia is a learning disability (LD) that affects a person’s ability to read. A person with dyslexia might also have trouble with other language skills, such as writing, spelling, and pronouncing words.
Read on to learn more about the types and subcategories of dyslexia.
:max_bytes(150000):strip_icc()/GettyImages-1323528256-a39230fcf5a64ca19dc77bfad44e308c.jpg "The Types of Dyslexia (1)")
Types of Dyslexia
There are no medically official “types” of dyslexia. Instead, all types fall under the larger category of dyslexia. However, the types allow educators to proceed with individualized plans to improve someone’s reading fluency most effectively.
Under the umbrella category of dyslexia, researchers have identified different types based on the cause.
Developmental
Developmental dyslexia is present from birth. This type includes primary and secondary dyslexia.
- Primary dyslexia is due to inherited genes or a genetic mutation. Some estimates suggest that 40% to 60% of children whose parents have dyslexia will also develop this learning disability. In primary dyslexia, dysfunction is in the left side of the brain—which is involved in reading—and affects a person’s ability to process language. It’s more common in males than females.
- Secondary dyslexia is caused by issues with neurological development during the fetal period (in the womb). As with primary dyslexia, the symptoms of secondary dyslexia are present starting in early childhood.
Acquired
Acquired dyslexia, also known as trauma dyslexia or alexia, appears in childhood or adulthood as the result of an injury or illness. This could be brain trauma, stroke (brain injury due to a blocked blood vessel or bleeding in the brain), or dementia (a progressive decline in memory, thinking ability, and behavior).
Dyslexia and Intelligence
Dyslexia, also known as reading disorder, is a language-based learning disability that affects a person’s ability to read. Most people with dyslexia have average or above-average intelligence, so their difficulties with reading are unexpected.
Subcategories of Dyslexia
In addition to the main types of dyslexia based on cause, researchers and educators often refer to subcategories of dyslexia based on how they are experienced: phonological, surface, rapid naming, double deficit, visual, and deep. Each of these subcategories is associated with a specific cluster of dyslexia symptoms.
Phonological
Phonological dyslexia affects a person’s phonemic awareness, which is their ability to break words down into individual sounds. People with this kind of dyslexia can often process and understand whole words, but not the individual sounds that make them up. They have trouble decoding and sounding out words.
Surface
People with surface dyslexia have trouble recognizing familiar words on the page and matching printed words to their sounds. This makes it hard for them to memorize and remember words, even ones they’ve already learned.
Rapid Naming
If someone has trouble naming letters, colors, and numbers quickly, they might have rapid naming deficit dyslexia. This type of dyslexia involves difficulties both with reading pace and language processing.
Dyslexia and Specific Learning Disabilities
Under the Individuals with Disabilities Education Act (IDEA), dyslexia is categorized as a specific learning disability (SLD). Other specific learning disabilities include dysgraphia (impaired letter-writing) and dyscalculia (difficulties with math).
Double Deficit
People with double deficit dyslexia have issues in two different areas of reading, such as rapid naming and phonological awareness.
Visual
Visual dyslexia is likely caused by issues with the parts of the brain involving visual processing. People with visual dyslexia often have a hard time remembering what they just read. They might also have trouble with spelling, forming letters, and other aspects of writing.
Deep
Deep dyslexia is a form of acquired dyslexia that results from trauma to the brain’s left hemisphere. This type of dyslexia affects someone’s ability to sound out nonsense words. It also involves semantic errors—substituting one word for a related one while reading (think “avenue” for “road” or “feline” for “cat”).
According to the International Dyslexia Association, dyslexia is the most common learning disability and the most common reason for difficulties in reading, writing, and spelling. It's estimated that 5% to 10% of the population has dyslexia, although some estimates are as high as 17%.
Diagnosing Dyslexia
While symptoms of dyslexia can affect someone at any time, it's usually diagnosed in childhood. There's no single standardized test for dyslexia. Instead, after ruling out other possible causes for reading difficulties (such as hearing or vision problems), your healthcare provider can make a referral to a psychologist for an assessment.
In addition to prior evaluation reports, school reports, and family history, a psychologist will evaluate you or your child for the following symptoms of dyslexia:
- Poor reading comprehension
- Problems with pronouncing words
- Delayed speech
- Inability to rhyme
- Being unable to tell left from right
- Letter reversal
- Mirror/“backward” writing
- Writing difficulties
- Confusing letters with each other
- Poor grammar and sentence structure
- Slow reading
- Poor spelling
The assessment will include the results of the evaluation, as well as suggestions for improving reading ability at home and school.
Can You Self-Test For Dyslexia?
There are some preliminary online self-tests for dyslexia offered by organizations like the International Dyslexia Association.
However, if you or your child has trouble with reading, it’s best to tell your healthcare provider right away. They can give you a referral to a psychologist or any other specialist who can assess the possibility of dyslexia or any other health condition.
How to Cope With Dyslexia
After learning that your child has dyslexia, it’s important to address the problem as early as possible. While people can learn to read at any age, early intervention—ideally in kindergarten or first grade—has the best prognosis.
Work with your child’s school to devise a plan to help them learn to read fluently. At home, consider seeking out a reading tutor for more structured reading practice.
Here are some of the ways you can help your child learn to read if they have dyslexia:
- Structured literacy instruction: Structured literacy instruction is an intensive method for teaching children to decode words. This method uses multisensory learning, phonics instruction, and phonological awareness to help kids learn to sound out words and process language more quickly.
- At-home exercises: It’s important for people with dyslexia to practice daily independent reading at home. A psychologist or school counselor might recommend specific exercises to help your child learn to read and process language, such as tracing letters with their finger or using flashcards to sound out words.Reading out loud to your child can also help.
- Developing an Individualized Education Plan (IEP): If your child receives a diagnosis of dyslexia, you can work with their school to develop an Individualized Education Plan (IEP) to suit their particular educational needs. Accommodations might include extra tutoring or additional time to complete tests and assignments, among others.
Is There a Cure for Dyslexia?
There's no cure for dyslexia. However, with early intervention and a solid support system, most people with dyslexia can learn to read fluently.
Summary
Dyslexia is a learning disability that affects a person's ability to read. Someone with dyslexia may also have trouble spelling, writing, and pronouncing words. The main types of dyslexia based on the cause are developmental and acquired.
Developmental dyslexia is present at birth. Acquired dyslexia occurs after injury or illness, such as stroke, brain trauma, or dementia. Subcategories of dyslexia include phonological, surface, double deficit, visual, deep, and rapid naming deficit.
Symptoms of dyslexia often appear during early childhood. People with dyslexia can learn to read, write, and spell using structured literacy instruction and at-home reading exercises. An IEP may be developed for children with dyslexia to improve their performance at school.
