Dyslexia is a specific learning disability that is neurobiological in origin. It is characterized by difficulties with accurate and/or fluent word recognition and by poor spelling and decoding abilities. These difficulties typically result from a deficit in the phonological component of language that is often unexpected in relation to other cognitive abilities and the provision of effective classroom instruction. Secondary consequences may include problems in reading comprehension and reduced reading experience that can impede growth of vocabulary and background knowledge.
* Adopted by the IDA Board of Directors, Nov. 12, 2002.
Reversals are common in the early stages of learning to read and write among average and dyslexic children alike. It is a sign that representations of letters and spellings of words have not been firmly established, not that a child necessarily has a reading disability (Adams, 1990).
The consensus based on a large body of research (e.g., Rayner et al., 2001; Lyon et al., 2003; Vellutino, Fletcher, Snowling, & Scanlon, 2004) is that dyslexia is best characterized as a problem with processing the sounds of language, not a problem with vision.
As frustrating as this is to hear as a parent, the answer depends on two factors: (1) whose definition of dyslexia you are using and (2) whose criteria you are using.
As far as the definition goes, dyslexia is widely characterized by difficulties with accuracy and fluency in word reading along with poor spelling and poor decoding. These weaknesses are unexpected when we look at a child’s intelligence and their opportunity to engage in effective reading instruction. Many experts believe dyslexia comes from underlying difficulties in the phonological component of language, so early on children with dyslexia may show difficulty breaking words apart into their individual sounds, putting individual sounds together to make words, isolating sounds in words, and rhyming.
Regarding which criteria is used to determine dyslexia, there is not a consensus. In the schools, we are bound by federal and state criteria for determining a specific learning disability, which includes dyslexia. Schools are required to first make sure the child has been exposed to effective reading instruction and additionally look at how the child responds to reading intervention and/or discrepancies between the child’s intellectual ability and academic skills. Outside of the school setting, private agencies often adhere to the DSM-5 definition of a specific learning disorder, which includes dyslexia, and generally agree that a child’s reading must be well below average. However, some dyslexia advocates believe any child who is even slightly below average in word reading, spelling or decoding, should be identified as dyslexic. It is therefore possible that an outside evaluator may report dyslexia even when the school may not find that eligibility.