Monday, May 7, 2007

dyslexia as being a visual problem

“My child can’t read… and the school told me its because he has dyslexia… he reverses his letters and they said that he gets the letters all jumbled. They said that it had something to do with his vision and as a result, he can’t read. Now what? Do we get an eye examination?"

Hmmmm… letters jumbled up meaning that you can’t raed? Are you albe to raed this eeven thugoh the ltteres are all mxied up? Aoccdrnig to rscheearch at Cmabrigde Uinervtisyity, ltteer odre deos not mttaer… the iprmoatnt ptar is taht the frist and lsat ltteer be in the rghit pclae… the rset can be a taotl mses and you can sitll raed it wouthit a porbelm. So… is dyslexia related to letters being jumbled up? Is dyslexia a disturbance of visual configurations of letters?

Research (see Dr. Jack Fletcher) among children reveals that phonetic or speech sounds processing is the most commonly the primary underlying disorder in dyslexia. Other contributing factors to low achievement in reading (or dyslexia which means a disturbance in reading) include low vocabulary and limited experience with reading (ie., few repetitions, insufficient time spent reading, etc.). Need to rule out reduced visual acuity as a contributor to slowed reading, headaches in the afternoon… by all means, please get an eye examination. But, dyslexia as being a visual problem? Hmmmm… maybe not.

So, how do I know if my child has dyslexia”? Well, dyslexia simply indicates a disturbance in reading… Is your child reading significantly below the level of his or her peers? If so, then he or she has dyslexia or a reading disorder. Unfortunately, dyslexia or the formal diagnosis of a reading disorder does not communicate anything beyond the symptom description. The real task is identification of factors that contribute to reading problems. In the past, various models have been employed to classify reading disorders with the discrepancy model holding court for the past 25+ years. The discrepancy model defines a reading disorder in terms of a significant discrepancy between reading achievement (lower) and abilities (higher) with some suggestion or assumption of a significant verbal (lower) vs. perceptual-motor (higher) processing discrepancy.

However, recent reviews of research (see Fletcher, J.M., Francis, D.J., Morris, R.D. and Lyon, G.R.. “Evidence-based assessment of learning disabilities in children and adolescents”, Journal of Clinical Child & Adolescent Psychology, 2005, Vol. 34, No. 3, Pages 506 – 522) indicates that this model has serious psychometric problems (meaning research cannot reliably replicate it). More recent work suggests that, while low reading achievement is the critical element for classification as a reading disorder (by definition), an evidence-based assessment must include an analysis of reading components (ie., see, discriminate letters, associate letters to sounds, put sounds together to make words, put words together to form sentences/ideas, formulation of themes and output) so that interventions are directed towards the weakest link in the chain of reading.

In addition, the work of Fletcher, et. al. (2005) calls for “a stronger underlying classification that takes into account relations with other childhood disorders” including a need for assessment of abilities (hardware), skills (acquired) and coping resources (ie., family support, teachers, educational instruction, etc.).


Dr. Richard Dowell is a Neuropsychologist located in Pennsylvania. Dr. Dowell evaluates upwards of 400 children and adolescents each year. In addition, Dr. Dowell is recognized as one of the top Forensic Neuropsychological witnesses in the North East.

Dr. Dowell can be contacted at

For more information on Neuropsychology visit

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