How dyslexia is diagnosed

Diagnosis Dyslexia and tablets. Medicine concept.

When dyslexic children get help early they have a better chance of becoming able readers. In order to get that help, your child needs a diagnosis.

The information presented here focuses on Canada, but there are many similarities in the US, UK and Europe.

Getting the diagnosis

1. To get a formal diagnosis, you must be tested for dyslexia. A dyslexia test is usually conducted by a registered psychologist. The test is called a “psychoeducational assessment” (or “evaluation” in some parts of the world). You can request the test from your school psychologist or a private psychologist.

Some private tutors will screen for dyslexia, and there is a greater push to use online screeners (tests). The idea is to catch kids early and get them the help they need, rather than waiting for an assessment. And, not everyone can afford the assessment.

It’s important to note that currently in Ontario, only assessments conducted by registered psychologists are accepted as official proof of diagnosis by most schools, employers or governments.

  • Reality check: In Canada, parents may request a psychological assessment or evaluation through their child’s school (for free), however the wait lists are very long. Many families hire a psychologist to get the assessment done, and to get a diagnosis. Unfortunately, many can’t afford the cost–and this is leaving many children without proper supports.

2. A diagnosis allows you to find specifically what type of intervention you or your child needs. A dyslexia diagnosis can be empowering; it’s a tool to help you or your child understand their weaknesses and strengths. I got diagnosed at age 49, and it changed my life for the better.

  • Reality check: In Canada, even with the diagnosis, most schools don’t provide much support. You may get accommodations, but most parents hire tutors to get their children reading instruction.

Resources for parents:

When to get your child assessed? The earlier the better

In Ontario, the medical community has set out specific guidelines recommending early assessment (diagnosis) and intervention:

  • In October 2018, the Ontario Psychological Association’s updated its Guidelines for Diagnosis and Assessment of Children, Adolescents, and Adults with Learning Disabilities (page 22) recommending that children be screened for learning disabilities as early as kindergarten or grade 1 in order to provide effective intervention.
  • In 2018, PONDA (Physicians of Ontario Neurodevelopmental Advocacy group) released an updated version of their advocacy toolkit for literacy based learning disabilities (namely, dyslexia). The goal is to promote “evidence based interventions for children with literacy based learning disabilities in all schools in the province of Ontario.”

Note that in Ontario, our Ministry of Education special education guidelines don’t yet reflect the recommendations of the medical community.

What happens at an assessment?

Psychoeducational assessments may seem scary to some, but I’ve been through one and it was painless: at times it was fun and interesting, and other times stressful and tiring. The test is designed to find your child’s learning weaknesses and strengths. It usually includes an IQ assessment (though this is not required for a dyslexia diagnosis as dyslexia is not related to IQ).

Your child will complete a series of tests, including word and math games, puzzles, reading exercises, over two or three (usually half-day) sessions. You and your child’s teacher will also be asked to fill out some forms.

When all that is done, your psychologist will prepare a written report, which includes the diagnosis and recommendations for what kind of support your child needs. Be prepared to be surprised: dyslexia may be diagnosed, but another learning, attention or mental issue may be identified (not all learning challenges are caused by dyslexia). In other cases, no diagnosis may be made.

Here is an inside look at a dyslexia evaluation [Understood video].

What is dyslexia? Diagnosis and definitions

The International Dyslexia Association definition:

Dyslexia is a neurologically-based, often familial, disorder which interferes with the acquisition and processing of language. Varying in degrees of severity, it is manifested by difficulties in receptive and expressive language, including phonological processing, in reading, writing, spelling, handwriting, and sometimes in arithmetic.

The world’s two main medical diagnostic guides define dyslexia as follows:

DSM-5 (Diagnostic and Statistical Manual of Mental Disorders)

Dyslexia is categorized as a “specific learning disorder” in the DSM-5 (published in 2013), which is the handbook used by health care professionals in the United States and internationally. It is considered the authoritative guide to the diagnosis of “mental disorders” (though it is troubling that dyslexia is categorized as a “mental illness“).

DSM-5 was a change from the previous edition, which included dyslexia as a distinct category:

“Specific Learning Disorder” has become the umbrella term for mathematics, reading, and written expression disorders in the updated DSM-5. The DSM-IV previously classified these as separate diagnoses. Instead, these disorders are now housed under one diagnosis with added specifiers (e.g., specific learning disorder with impaired reading).” (source:


ICD-II (International Classification of Diseases)

Dyslexia is categorized as a Developmental learning disorder with impairment in reading” in the new ICD-II guidelines (published December 2017). The criteria are part of a highly anticipated update to the “International Classification of Diseases,” a diagnostic manual produced by the World Health Organization (WHO).


After the diagnosis (getting help)

If you decide to share the diagnosis with your child’s school, your school will review the report’s recommendations and provide dyslexia support based on their special education guidelines. It’s helpful for you, as a parent, to ask for and review these guidelines to see what support is available.

Support may come in the form of specialized reading instruction and accommodations. When you don’t get this support, consider a tutor specializing in structured literacy if you can afford it.

  • If you live in Canada, check out the Ontario Branch of the International Dyslexia Association for a list of qualified tutors.

In Ontario, a diagnosis of dyslexia is considered an “exceptionality” and that means your school is required by law to provide support. But don’t be surprised if you don’t hear the word dyslexia at your school. You may hear “specific learning disability,” “reading disability” or “learning disability.” In Ontario, new draft guidelines have dropped the word altogether, defining it broadly as a learning disability under the “Communicational” exceptionality:

Ont spec ed 1Ont spec ed 2

More information

Three approaches to understanding and classifying mental disorders (2017)