IQ Testing and Dyslexia

The following was taken from the Testing & Evaluation Fact Sheet on the website. Has this changed? According to ADAAA, is an IQ test required for the identification of dyslexia?


"Until recently, an intelligence test was considered to be a necessary part of the evaluation because the diagnosis of a learning disability was based on finding a significant difference between IQ and reading skill. Poor achievement despite average or better intelligence was considered a key indicator. Current regulations no longer require that such a discrepancy be present when making a diagnosis. This change in the regulations came about because many studies have shown that intelligence is not the best predictor of how easily a student will develop written language (reading and spelling) skills. Instead, oral language abilities (listening and speaking) are considered the best predictors of reading and spelling.

"A formal measure of intelligence is not always needed to document average intellectual abilities. For younger children, parent information about language development and teacher information about the child’s ability to learn orally may indicate average intellectual abilities. For older students or adults, past achievement in school or work may indicate at least average intelligence.”

Dr. Pierson's Response: 

The information you highlighted is indeed the current thinking when conducting an evaluation and making a diagnosis of dyslexia. We no longer benchmark against IQ for the very reason listed—oral language is a better predictor. We now look for a pattern of strengths and weaknesses, with those weaknesses being in an area of phonological processing, including phonemic awareness, phonological memory, or rapid automatic naming, which then affects learning letter-sound correspondences to decode and spell. We do want some indication of average intelligence, which can be indicated by vocabulary, oral language skills, and/or achievement in non-linguistic areas. I refer you to the definition of dyslexia that we have on the website—the child's difficulties with reading (and spelling) are unexpected in light of other areas of development.

That said, when conducting an assessment, we want to be mindful that a child’s language scores can degrade over time if he or she does not have access to the curriculum commensurate with his or her peers. When children are first learning to read, their oral language skills help them make meaning of the words they are trying to decode. If you have been to a zoo and know what an elephant is, then it is a lot easier to figure out the new word in text when you read, "The man laughed when he was sprayed with water from the elephant’s trunk."

But then, as children get older, beginning in 3rd grade and then solidly by 4th grade, reading becomes one of the primary ways children learn vocabulary and are introduced to more sophisticated linguistic forms. Students are now using their reading skills to learn. Thus, children with dyslexia, reading disability, or language disorder are at great risk to keep up with their peers given that they cannot read (i.e., don’t have access to) the same text. This is why it is important, early on, to get a measure of a child’s understanding of spoken vocabulary. It is an important baseline score to have. It not only serves as a reference point from which to compare the student’s other oral and written language skills, but we know that as children get older, reading contributes to vocabulary development. It is important to monitor and ensure that the student is continuing to learn the vocabulary that one’s peers are exposed to when they read. That is why I recommend that kids with dyslexia have access to texts via audiobooks; and, they should follow along with the written text while it is being read aloud. Research has shown that the more one reads, the better reader one becomes.