How To Test For Dyslexia: Find out more

Do you or someone you know make frequent reading, spelling, or speech mistakes? For example, mixing up words or writing backward? Are grammar and understanding textbook information a struggle? What about reading comprehension? Is it difficult? If you answered, “yes,” to any of these questions, a diagnosis of dyslexia is a possibility. Continue reading to learn more about how to test for dyslexia.

How To Test For Dyslexia
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What is Dyslexia?

Dyslexia is a language-based learning disability that affects oral and written language skills. The disorder impacts the specific areas of the brain that process language. As a result, dyslexia makes it difficult to perform reading, writing, spelling, and speech tasks. Approximately 20% of the population suffers from dyslexia. Both children and adults possess normal intelligence. The problems with language arise from the inability to decode phenomes, the basic sounds of speech, into identifiable words.

Who Should Be Evaluated For Dyslexia?

Dyslexia is the most common learning disability. It can affect any race, gender, or age. However, the disorder is often evident in early in life as children begin school. Switching letters is common as children are learning to write, but dyslexia should be suspected if they also show deficits in reading. Anybody with the following signs that should consider dyslexia testing:

  • Reading below expected age-related reading level
  • Mispronouncing words
  • Confuses words
  • Delayed speech milestones (late talking, slow to learn new words)
  • Difficulty spelling
  • Poor memory
  • Cannot recognize rhyming patterns
  • Letter reversals
  • Misunderstanding jokes

How To Test For Dyslexia: Case History

Typically, teachers or parents notice the first signs of dyslexia and an educational psychologist makes the diagnosis. However, a general practitioner, neurologist, or standard psychologist is qualified to assess for the disorder. There is no test to diagnose dyslexia. The diagnosis depends on a number of factors such as a full case history, which includes educational and medical background, a psychological evaluation, neurological testing, and an assessment of each of the language and cognitive skills potentially affected by dyslexia.

Educational History

Being that dyslexia profoundly impacts academics and education, the first step in testing for dyslexia is taking a thorough educational history. The clinician performing the evaluation focuses on patterns of learning: What grades does the student receive in school? Did they learn to read on time? Do they currently read at the expected reading level for their age? Do they read slower than their peers and struggle to speak, understand, or follow the teacher’s directions? Language is so engrained in education that knowing how the student learns lends considerable insight into the skills affected by dyslexia. An educational history must rule out factors infrequent school attendance and limited educational opportunities.

Medical History

While dyslexia does not cause medical problems, a medical history is mandatory in the diagnosis. Medical history is important because those with dyslexia do not have an underlying medical reason for their symptoms. Vision and hearing tests are normal. The presence of a medical cause such as poor vision or hearing may negate the diagnosis. As part of the medical history, developmental milestones are relevant in assessing dyslexia. People with dyslexia are more prone to delays in reaching specific milestones such as speech. They may learn to talk late or be slow to learn new words.

Psychological Assessment

Some psychological disorders mimic the symptoms of dyslexia or exacerbate the symptoms. Studies reveal over half of the samples with the learning disorder dyslexia have co-existing neuropsychological conditions like attention deficit hyperactivity disorder, mood disorders, anxiety disorders, and language disorders. The psychological assessment helps determine if a comorbid mental disorder is worsening the difficulties with reading, writing, and verbal expression. It also rules out whether the symptoms of dyslexia are actually dyslexia, which is NOT a mental disorder, versus psychological manifestations.  

Neurological Tests

To be thorough, those suspected to have dyslexia undergo a series of neurological tests. This includes vision and hearing assessments, as well as brain tests. The doctor is likely to order brain scans, which take images of the patient’s brain to rule out any medical cause for symptoms.

How To Test For Dyslexia: Intelligence Quotient (IQ)

The abbreviation IQ stands for intelligence quotient. An intelligence quotient test measures intellectual potential or intelligence—meaning someone’s capacity for learning, problem-solving, critical thinking, reasoning, logic, and other cognitive processes. IQ is reflected as a number. The Wechsler Intelligence Scale for Children is frequently administered to school-age children. While assessing for dyslexia, clinicians look for discrepancies between IQ scores and academic achievement because those with dyslexia possess average intelligence.

How To Test For Dyslexia: Phonological Awareness

Phonological awareness comprises the sounds of language. It is the ability to identify phonemes, which are the sounds in words, and then blend those sounds into words. Inadequate phonological awareness is the primary characteristic of dyslexia. Testing phonological awareness is integral to the diagnosis because it predicts one’s risk of reading failure. Manifestations of poor phonological awareness differ with age but can include difficulty rhyming, omitting word sounds, and adding additional word sounds.

Testing phonological awareness entails blending and segmenting words. For example, knowing the remaining sound of a word after removing the first sound or filling in the middle sound of a word (i.e. “tel” “phone” with the middle sound being “e”).

How To Test For Dyslexia: Decoding

Using knowledge of letter-sound relationships to pronounce words, decoding is the process of applying phonological awareness. It involves distinguishing letter patterns, matching the sounds that form each letter, and breaking words into syllables. Decoding helps identify words the child may have heard but is unfamiliar with the written format. For example, the suffix “-cy” sounds like “c” and makes decoding words such as “privacy” easier.

Since dyslexia affects the speed and accuracy of decoding, the skill is often part of the evaluation. Presenting the child with both real and fake words with no meaning, and having them decode those fake words, tests decoding because they are matching sounds to letters.

How To Test For Dyslexia: Spelling

Spelling is another process of applying phonological awareness and decoding, as it requires the knowledge of pairing word sounds with individual letters. The skill of spelling is typically weak in dyslexia due to the poor ability to recognize patterns of letters that spell one sound (i.e. “ea” in “heat” and “seam”). Decreased spelling scores are indicative of underdeveloped language components like phonological awareness, vocabulary, grammar rules, and writing common amongst the dyslexic population. Studies reflect that low spelling proficiency (orthographic processing) in those with dyslexia greatly impairs writing despite a lack of dysgraphia.

How To Test For Dyslexia
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How To Test For Dyslexia: Oral Language

Dyslexia has the potential to affect speech. Low-level language skills consist of the skills commonly lacking in dyslexia like recognizing word sounds, and high-level language skills are the ability to carry a conversation and understand verbal age-appropriate vocabulary or verbal direction. Dyslexia creates normal high-level skills but decreased low-level language skills. Speech delays are not unfounded in young children, yet adequately develop by school-age.

Assessing speech is relevant in testing for dyslexia because the presence of high-level language deficits indicates the need for further testing by a speech pathologist to eliminate language impairment as a diagnostic possibility. A speech pathologist can access multiple elements of oral language—articulation, narrative discourse, phonological awareness, and oral language comprehension.

How To Test For Dyslexia: Word Recognition

Word recognition is the ability to recognize and read written words. While people with dyslexia can correctly identify words, they often display a delay prolonged amounts of time to do so. Testing for word recognition measures time and accuracy simply by reading printed words from a list without the use of cues and context clues from a full sentence.

How To Test For Dyslexia: Fluency

Fluency is the combined scores of reading accuracy and the rate (speed) one reads. Low levels of fluency interfere with reading comprehension and suggest deficits in phonemic awareness, decoding, and vocabulary. Testing fluency is essential in diagnosing dyslexia. The disorder leads to a lack of fluency; however, accuracy remains near normal measures.

Rapid Automatized Naming Test

Since those with dyslexia have deficits in visual and/or auditory processing, tests measuring naming speed are useful in evaluating fluency. The Rapid Automatized naming Test presents sets of numbers, letters, objects, and colors on a card. The participant is asked to name the card as quickly as possible. Naming tests with letters are ideal for dyslexia evaluation.

How To Test For Dyslexia: Reading Comprehension

Reading comprehension is understanding the meaning of written words. It is evaluated by having someone read a passage and answer questions about the main idea of what was read. Typically, the passage is available for reference throughout the test. Many with dyslexia have normal reading comprehension in that they understand the main idea of short reading passages, but still have considerable difficulty reading words and fail to retrieve enough content from longer, more complex reading passages to comprehend the main idea. Contrarily, there is a subset of dyslexics who do read fluently and struggle with accurate reading comprehension. To thoroughly judge reading comprehension, tests should measure silent reading comprehension and oral comprehension.

How To Test For Dyslexia: Cognitive Skills

Cognitive skills are the skills we use to learn, process thoughts, remember information, and sustain attention. These skills are highly involved in reading and language. With their prevalence in language, cognitive skills like working memory, attention, and verbal reasoning are undoubtedly impacted by dyslexia. Evaluating these cognitive skills is an important step in testing for dyslexia.

Working Memory

The International Dyslexia Association reports weaknesses in working memory ranging from 20 to 50 perfect in those with dyslexia. Working memory is a cognitive skill characterized by the ability to retrieve, manipulate, and then apply the information within brief periods.

Poor working memory is linked to deficits in reading comprehension and reading fluency. A complete assessment of working memory is measured through recall tests. The student being tested is given a written word, digit, or sentence and must repeat it back in regular time intervals. Verbal working memory is the same process, but with listening recall rather than printed.


Attention is the cognitive process in which one selectively focuses on information while ignoring irrelevant stimuli. Recent studies suggest attention deficits may contribute to reading difficulties in dyslexia. Upon testing, dyslexic participants had marked deficits in alertness, covert shift of attention, divided attention, flexibility, and visual search. Attention is also crucial because comorbid disorders, like attention deficit hyperactivity disorder (ADHD), can occur along with dyslexia. Testing attention ensures clinicians rule out these potentialities before diagnosing dyslexia.

Verbal Reasoning

Verbal reasoning is essential for higher-order thinking processes. It is described as “understanding and reasoning using concepts framed in words” and then forming conclusions and new ideas based on that information. Examples of verbal reasoning are learning to read, following verbal directions, and having a conversation. Those with dyslexia are prone to deficiencies in verbal reasoning because they are unable to make sense of information, which is related to the skills of reading, writing, and verbal communication.

The test for verbal reasoning is similar to that of reading comprehension in the sense that the person is provided a passage of test, but instead of answering questions about the main idea, verbal reasoning tests are followed by one or more multiple-choice true or false statements.


Berninger, Virginia W, and Robert D Abbott. “Differences between Children with Dyslexia Who Are and Are Not Gifted in Verbal Reasoning.” The gifted child quarterly vol. 57,4 (2013): 10.1177/0016986213500342. doi:10.1177/0016986213500342

CNRS. (2017, November 28). Dyslexia: When spelling problems impair writing acquisition. ScienceDaily. Retrieved January 13, 2020 from

Margari, L., Buttiglione, M., Craig, F., Cristella, A., de Giambattista, C., Matera, E., … Simone, M. (2013). Neuropsychopathological comorbidities in learning disorders. BMC neurology, 13, 198. doi:10.1186/1471-2377-13-198

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