Friday, August 8, 2008

Understanding Dyslexia - Science-based Definition of Dyslexia

I just listened to a recording of a keynote address given by Dr. Joseph Torgesen of the Florida Center for Reading Research at the 2nd Annual Reading Conference for the Utah Branch of the International Dyslexia Association. He shared an interesting science-based definition of dyslexia:
Dyslexia is a specific learning disability that is neuro-biological 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.”

NOTE: Emphasis added by Torgeson.
(Source: Lyon, G. R. & Shaywitz, S. E. (2003). A definition of dyslexia. Annals of Dyslexia, 53, 1-14.)


  1. Shaywitz is stuck on a phonological cause of dyslexia and so defines dyslexia in that way. There are also visual dyslexics that have visual problems that cause reading problems without having phonological problems.

    Children with phonological problems can be identified preschool as being at high risk of having dyslexia.

    Visual dyslexics without phonological problems can not be identified preschool. They only encounter problems when exposed to print as properly seeing print is their primary problem.

    Visit for information on how to tell the difference between dyslexia and visual dyslexia.

  2. Thanks for sharing your perspective, John. I'm looking forward to checking out the link you provided.

  3. My daughter has had a year of the orton program and is able to now decode words to some degree. Because of this they say she is not dyslexic. Prior to doing the orton program she did not know her sounds. She also has and auditory processing deficit in discrimination. She spells words as she hears them. Reading is extremely difficult and she does not read and is falling behindwith vocab. I am very frustrated. I know my daughter is dyslexic, it runs in our family, but cannot get the proper diagnoises. Can you help?

  4. Amie,

    Thank you for your comment. I'm sure it must be frustrating to feel like you aren't getting a proper diagnosis for your daughter. What grade is she in?

    I'm going to pass along your comment to a colleague of mine who specializes in tutoring children who are dyslexic and see what she suggests.

    I wish you and your daughter the very best.


  5. Amie,

    I contacted my colleague whom I referred to in my last comment, and this was her response:

    This is a problem that happens a lot. Because of the work I have done with my son, he no longer tests as dyslexic, but he still needs help. It is very frustrating. She can only talk to teachers and hope they will help with accomodations without an official diagnosis. I could talk to her about APD (auditory processing disorder) as well. Why don't you offer for her to call in and ask for me?

    Amie, her name is Shantell Berrett, and she can be contacted at 800-333-0054. I hope this helps!