There has been so much discussion surrounding the causes of dyslexia that most people simply need a bottom line. If you truly would like the epidemiology of dyslexia then we would highly recommend you familiarize yourself with the work of Sally E. Shaywitz, who is the Co-Director of the NICHD-Yale Center for the Study of Learning and Attention.
For those of you who are simply searching for some basic facts this page is for you.
But first, we want to provide a little background and some clarification regarding some of the common myths about dyslexia.
Yes, dyslexia is both familial and heritable. There are genetic influences that can cause dyslexia. Specifically, studies have identified certain chromosomes that can be passed down from parents to children. 23-65% of children who are identified with dyslexia also have a parent who was dyslexic. This information provides us with opportunities for early identification and proactive intervention, which is good news.
No, the cause of dyslexia is not the visual flipping of letters or seeing words backwards. Honestly, this common misperception is frustrating. Too many people believe dyslexia means seeing letters and words backward. This belief is simply not supported by research. The backward writing and reversal of letters and words are common in the early stages for writing development for most children. Reversals are irrelevant to the diagnosis of dyslexia.
There are two main causes for dyslexia:
Cause #1 Neurological - The classic dyslexic is born with a glitch in his or her posterior reading system. A neurological problem exists that prevents children from easily establishing reading fluency.
Cause #2 Environmental – Here children develop into poor readers mainly as a result of experience. Their reading struggles may be the result of poor reading instruction, a disadvantaged language environment at home or a combination of both. With these children, the neurological system is just fine but because it is never activated appropriately at an early age, it does not function properly.
That is it! Two causes for dyslexia. And you thought you needed to read a dissertation to understand what causes dyslexia. Either the brain is predisposed or the environment creates the reading problem. Pretty simple, huh?
It is easy to understand why we are so passionate about quality reading instruction at ReadingResource.net...it simply prevents a lot of learning disabilities! With the research we have available to us now, there is absolutely no reason poor reading instruction should continue to exist as one of the causes of dyslexia.
For those who teach reading, it is important to understand how the brain reads and the difference between the brain of a nonimpaired reader versus the dyslexic reader. We will cover this information soon on a separate page. Check back for the link right here!