Diagnosing Dyslexia

No Single Test Exists for Learning Disabilities

Dyslexia is a learning disorder that affects language processing. Early detection and intervention provide an opportunity for children to succeed.

When a child is having difficulty with reading, spelling or writing, parents or teachers may refer a child for testing to determine whether there is a learning disability. Dyslexia is one of the most common types of language processing learning disability. There is no single test to determine if a child has dyslexia. Instead, testing includes an evaluation in a number of different areas:

Background Information

The evaluation includes compiling background information on the child. This includes information on early development, family history, and educational history and is provided by both parents and teachers.

IQ Testing

IQ testing, once standard in evaluations for dyslexia, is no longer required. Children may or may not be tested for IQ in the evaluation. Testers look for at least average intelligence, which can be measured by past school performance or information provided by parents on language development. Oral language skills are also used to measure where reading and spelling levels should be.

Oral Language Skills

Oral language skills include listening, understanding speech, and being able to express thoughts orally. Children with dyslexia normally have adequate higher-level oral language skills. They may have difficulty with lower-level skills such as recognizing or creating the sounds of letters in speech.

Word Recognition

Word recognition is evaluated by asking a student to read single words without the ability to use context clues. Accuracy in reading the word and the amount of time it takes to read the word (fluency) are important in this test.


Children are also evaluated on their ability to read words they are not familiar with. This is called “decoding” and the test includes nonsense words (strings of letters that may look like real words but are not).


Students are evaluated based on spelling skills. Children with dyslexia often have a very difficult time with spelling and often spell words exactly as they sound, leave out letters, or include additional letters in words.

Phonological Skills

Phonological skills include breaking words down into syllables and individual sounds. Students with dyslexia have trouble identifying and pronouncing the individual sounds. An evaluation for dyslexia would include testing on phonological processing.


Reading fluency is also tested. This includes how quickly a person can process information and read words. Cards containing pictures or colors are placed in a row and a child names them as quickly as possible.

Reading Comprehension

Reading comprehension is evaluated. Comprehension of oral stories is often higher than written stories. For some students with dyslexia, reading comprehension scores are average or above. This can be contributed to the short passages and the ability to find the answer in the passage. Reading comprehension when reading books or longer passages may not be as high.


Mastery of vocabulary is evaluated when testing for dyslexia. Good vocabulary skills are important to reading comprehension, however, students with dyslexia sometimes avoid reading and do not have the opportunity to improve vocabulary skills.

A thorough evaluation for dyslexia would include many, if not all, of these aspects. Many school districts do not test specifically for dyslexia but will test for overall learning disabilities. School testing may include only a portion of the above tests. Parents interested in having their child tested for dyslexia may need to find a private evaluator or psychologist knowledgeable in dyslexia and how it impacts a child’s life.


  • “Dyslexia”, 2005, CNN Health Library
  • “Evaluation: What Does it Mean for Your Child”, 2007, Pacer Center, LD Online
  • “Testing and Evaluation, 2007, The International Dyslexia Foundation