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Diagnosing Dyslexia: How Is Dyslexia Diagnosed?

How is dyslexia diagnosed?
Dyslexia, in the most basic terms, is a difficulty with words. Like all words that start with dys it refers to a problem, deficiency or lack. Lexia has to do with words and language. It shares an ancestry with other words like lecture. In particular, dyslexia refers to a difficulty with reading and writing words.

Because a learning difficulty is a multifaceted problem, it’s not always a straightforward matter to determine if one is present. In this respect, dyslexia is very different to a disease or medical disorder. It’s important to remember that dyslexia is not a disease. It’s better to think of it as a mode or way of learning that is not optimally attuned to the requirements of education. Thankfully, it is possible to assess a child in order to determine whether he or she has dyslexia.

Table of contents:

How a dyslexia diagnosis is made

A diagnosis of dyslexia can only be made after an extensive evaluation. This evaluation looks at a child’s ability to read, in addition to other factors such as general academic ability and family background. Typically, a large amount of information is required and the person administering the evaluation or assessment will take the child through a series of tests. This thoroughness is necessary, because it’s important to rule out other possibilities.

Remember, it’s possible for someone to read poorly, and not be dyslexic. A child may have a disruptive home life that has made learning difficult. Or, there might be a significant intellectual impairment. Neither of these is the same as dyslexia. To eliminate these and other possibilities, an assessment must take a wide range of information into account. Some of the components that go into a comprehensive educational evaluation are:

Tests of hearing and vision

These tests can establish whether a child has difficulties on the physical level. Of course, any difficulties in vision or hearing will be severely disruptive to the learning process.

Developmental histories, sociological and emotional background

An assessor will have an interest in any issues in a child’s development, whatever their nature. Even physical milestones such as crawling can be relevant here. Some theorists argue that crawling in infancy plays a crucial role in a child’s ability to learn later on. Other important factors are the child’s home life, and his or her ability to regulate emotion.

Tests of specific skills

In the course of an assessment, the child will work through a variety of tests. These gauge skills such as decoding, rapid naming and reading fluency. Others are designed to evaluate a child’s phonological awareness and overall vocabulary.

The clinician collates and interprets all of this information in order to determine whether any specific learning disability exists. The results of the assessment will also be used to give recommendations regarding the nature and extent of the intervention that the child needs in order to overcome any significant challenges.

What is the difference between dyslexia screening and dyslexia testing?

If you are considering getting an assessment for your child, it’s highly likely that you have noticed possible signs of a learning difficulty. Once a parent or teacher notices these signs, it’s a good idea to investigate. There are two methods for determining the nature and extent of a learning difficulty: screening and assessment. While they are related, there are some important differences between the two.

Firstly, screening is a method for identifying children who are at risk. This usually takes the form of a brief test. During this process, a child might be asked to match symbols to sounds, or recall information from a verbal prompt. Another common feature of dyslexia screening tests is rapid automatic naming (RAN), which requires the child to look at familiar objects, letters or numbers and name them quickly. Sometimes, a dyslexia screen is completed by parents. A positive answer to a question such as “does your child reverse letters?” might lead to a positive result on a screening test. Such a result is useful, but not conclusive.

These tests are by their nature not specific enough to justify a diagnosis. They are standardized tests that some schools use as a matter of course. But as we’ve seen, dyslexia is not a uniform phenomenon. Any two dyslexic children will have very different profiles in terms of their skills, abilities, strengths and deficits.

In contrast, a formal assessment is a personalized, detailed process that aims to paint a picture of a particular child’s strengths and weaknesses. If your child is screened and the result indicates that there might be a problem, this is something that the assessor should know about. While screening can yield useful results from a very early age (beginning at around five), a formal assessment is generally only recommended around second grade.

Who can make a dyslexia diagnosis?

In many countries, the ability to diagnose dyslexia is limited to certain qualified professionals. In the United States, there is no overarching law that defines who may provide a diagnosis. Generally, however, there is an understanding that one test on its own cannot be an adequate basis for a dyslexia diagnosis. For example, an audiologist may determine that a child has difficulty with auditory processing. This may be the cause of a child’s reading difficulty, but it is unwise to assume so, based on one test alone. The practitioners and clinicians who typically give dyslexia diagnoses use a battery of tests and measurements. As we have seen, a medical or physiological report may be integral to that process, but not sufficient on its own.

These are the professionals who most commonly issue diagnoses that can be used to acquire institutional support for dyslexia:


These are professionals who specialize in understanding how people think, emote and experience the world. There are many different types of psychologists. Often, educational psychologists are tasked with assessing children for learning difficulties. Educational psychologists are interested in how children absorb and process information. They also investigate the complex interaction between a child’s emotional and educational life. In the United States, the academic pathway for educational psychologists typically begins with a bachelor’s degree, followed by a master’s and then a PHD or PsyD.

Speech and language pathologists (SLP)

Because dyslexia concerns the act of reading, specialists in language acquisition are obviously well-placed to address it. They are often involved in a cluster of professionals who provide input on assessments of a child’s linguistic competence.

Occupational therapists

While occupational therapists usually play a direct role in the treatment of dyslexia, they can also contribute to diagnoses in some cases. They have specific expertize in the management of the environment for learning. For example, they observe how a child sits, stands and engages with the classroom. This enables them to draw conclusions about a child’s readiness to learn.


A neuropsychological assessment is a very detailed evaluation of a child’s performance in a wide range of areas. The goal is to determine whether a child’s cognitive abilities are adequate for the demands of mainstream education. A neuropsychologist will typically assess linguistic, sensory and intellectual ability through a large number of tests, some of which resemble games. 

Should I consult a medical professional?

Other professionals can be involved in the process of determining whether a child has a specific learning disability. An optometrist test is an easy way to determine whether a child’s vision is normal or deficient. Optometrists can test your child’s eyesight and check whether the eyes are functioning normally. If necessary, they can refer you out to an ophthalmologist, if an eye disease or disorder is suspected. This is an essential first step before seeking a dyslexia test, because the assessor will want to know that your child has no physiological deficits. Similarly, an audiologist can assess your child’s hearing to make sure that no hearing impairment is present. This is another useful piece of information to have before you seek out a dyslexia test.

What happens after a dyslexia test?

If your child is diagnosed with dyslexia after undergoing comprehensive assessment, you might be unsure of what to do next. For many parents, the first feeling they experience is relief. They finally have an answer to the question of why their child is not performing well at school. But the news can also evoke dread and fear. Understandably, many parents worry that dyslexia will be a lifelong obstacle for their children. The good news is that this need not be the case. Here are some things that you can do if you are in this situation:

Get an Individualised Education Plan (IEP) in place

A dyslexic child is not disabled in the conventional sense. However, dyslexia is classed as a specific learning disability. This means that a dyslexic child is entitled to additional support where necessary. In the United States, this is known as an Individualized Education Program (IEP). In order to qualify for the specialized support this entails, a child must have at least one of a number of impairments, one of which is a specific learning disability. The Individuals with Disabilities Education Act (IDEA) defines the responsibilities of all the parties involved. You as the parent are one of the parties to the legally enforceable contract that results from this. Other parties typically include your child’s teacher, a member of the school board and an educational specialist.

If your child does not qualify for special accommodations at school, but you have received a professional diagnosis of dyslexia, you can make use of Section 504 of the Rehabilitation Act, 1973.¹¹ This is a piece of civil rights legislation that prohibits discrimination based on ability. It is an alternative avenue to acquire additional services for your child, such as extra time on tests or educational support in the classroom.

Identify and nurture your child’s strengths

A child who is diagnosed with dyslexia may experience emotional distress, either from knowing about the diagnosis, or simply through perceiving their limitations at school. A great way to offset this is to focus on your child’s strengths, whatever they may be, in order to restore confidence. Dyslexia is not a disease; your child should not feel as if they are sick.

Consider online tutoring for dyslexia

Edublox offers live online tutoring to students with dyslexia, dyscalculia, dysgraphia and other learning difficulties. Our students are in the United States, Canada, Australia, New Zealand, and elsewhere.

Haven’t heard of Edublox before? Watch our explainer video below and visit our Testimonial Page for many stories on how Edublox training and tutoring has helped turn dyslexia around. Book a free consultation to discuss your child’s learning needs.

What are the different types of dyslexia?

Dyslexia, in the broadest sense, is a difficulty with words. Many people experience it, and to varying degrees. While dyslexia is receiving more attention than ever before, there are many questions that still don’t have conclusive answers. Thankfully, though, experts in the field have outlined some general patterns and trends. These can help us to understand what dyslexia means for your child. In a nutshell:

  • Not all dyslexia is the same
  • You can get to the root cause of the dyslexia through testing
  • Identifying this cause can direct you to the most appropriate type of help

You can think of a “type” of dyslexia as an indication of which skills your child needs to develop, rather than a diagnosis. Before we get to how a dyslexia test can help you to figure out what your child needs, let’s look at the various types of dyslexia that we know about.


One of the most common forms of dyslexia is called phonological dyslexia. As its name suggests, this type is connected to sound. Every language has a set of sounds that you have to know in order to speak it. These sounds are called phonemes. In order to speak, read and write a language, it’s not enough to be able to say phonemes. You also need to be able to link them to symbols. For example, in English, there are two sounds that we write with the letters “th.” Think about the difference between how you say these two words:

  • That
  • Think

When you read “that,” you put your tongue between your teeth and use your voice. When you read “think,” you do the same thing, but without using your voice. In other words, you decode the words. Decoding is what happens when you see a symbol and convert it into the right phoneme. A child with phonological dyslexia finds it hard to do this. If a child struggles with this part of a dyslexia test, then the result will probably indicate phonological dyslexia. Another name for the same problem is dysphonetic dyslexia.

This kind of dyslexia has some tell-tale signs. One of the most common is incorrect spelling that is hard to decipher. When a child selects symbols that are not well matched to the sounds, this can indicate that the problem is phonological in nature.

It seems that this is the most common type of dyslexia, which isn’t surprising when you consider how tricky English spelling is. The way you speak English, and the way you write it, are often quite different. Think about a word like “thorough.” To decode this word, we have to make decisions about how to pronounce “th” and what to do with the “gh” at the end. Contrast it with “rough” and you will see the problem. Children struggling with phonological dyslexia often have difficulty making the right decisions here.


For some people, the difficulty is not sound-based but more visual. For example, a child may find it hard to recognize a word, even if it’s not the first time he or she is seeing it. For a proficient reader, the shapes of words are immediately recognizable, almost like faces of familiar people. If a child scores poorly on the sight word module of a dyslexia test, the problem may well stem from an inability to recall these shapes.

This type of dyslexia has the name surface dyslexia. Because it relates to the way we see words, this type is also known as visual dyslexia. Another name for this is orthographic dyslexia. This term refers to the fact that visual dyslexia often causes problems for spelling, because orthography is another term for spelling. A fourth term that can appear in dyslexia tests is dyseidetic dyslexia. This is just an alternative way to refer to surface or visual dyslexia, depending on the preferences of individual practitioners.

One of the hallmarks of this kind of dyslexia is frequent confusion of letter symbols that look similar. For example, a child might not always distinguish “b” from “d”. There may also be problems in dealing with words that have irregular spelling or silent letters, such as “though”.

Interestingly, it’s very common for children to show signs of both phonological and surface dyslexia. This highlights the need for a multifaceted approach to addressing the problem in most cases.

What causes dyslexia?

It’s clear that not all dyslexia is the same. Two children who receive a dyslexia diagnosis might have very different strengths and weaknesses. It also seems that the origins of dyslexia vary between different cases. Among those researchers who believe that dyslexia is neurobiological in nature, there is ongoing discussion about whether its causes are environmental or genetic. In other words, we aren’t yet sure whether dyslexia, and the brain behaviors that seem to occur alongside it, are determined by genes, or caused by events in childhood development. The current consensus is that both are possible, and both exist in the population of dyslexic people. What this means is that there are people whose dyslexia is conditioned by their genes. This type of dyslexia is termed primary dyslexia. On the other hand, there are people with no genetic predisposition towards dyslexia, who nevertheless become dyslexic, usually quite early in their lives. The term secondary dyslexia is used to refer to this.

Primary dyslexia

Extensive cross-disciplinary research continues to seek answers about how genes affect learning in general, and reading in particular. Some studies have looked at the relationship between handedness and dyslexia. There is also some evidence that having a dyslexic parent can increase the likelihood of a child being dyslexic. This has not been proven conclusively, but it can be useful information for the clinician or expert administering a dyslexia test. However, you should not assume that a family history of dyslexia is necessarily the cause of your child’s reading difficulties. Importantly, even if there is a genetic basis to your child’s reading difficulties, this does not mean that the condition is untreatable or that your child will always struggle to learn.

A major factor to bear in mind is the role of neuroplasticity. Throughout life, but especially in childhood, the brain can and does create new neuronal networks in response to stimulation. This is what happens to the brain of a child who undergoes an adequate remedial intervention to improve reading skills. There is now a great deal of evidence that suggests the outlook for a dyslexic child can be greatly improved, especially if problems are identified and dealt with early on.

Secondary dyslexia

On the other hand, dyslexia can be caused by events that take place during infancy. In this case, it is not primary but secondary dyslexia. Some experts theorize that certain types of influences can influence a child’s ability to develop language skills. These are as wide ranging as a mother’s behavior during pregnancy, a failure to crawl, or even emotional and social conditions. If this includes traumatic events, either psychological or physical, this can lead to what is known as acquired or trauma dyslexia.

Authored by Susan du Plessis (B.A. Hons Psychology; B.D.), an educational specialist with 30+ years’ experience in the field of learning disabilities, and Dylan Arslanian (B.A. Hons Linguistics, Cambridge DELTA).
Medically reviewed by Dr. Zelda Strydom (MBChB).