Brooklyn Reading Center - What is Dyslexia?
Estimates of the prevalence of dyslexia in the general U.S. population range from 5% to 20%.*
A common belief about dyslexia is that it is a reading disorder caused by a visual perceptual problem that results in reading words backwards, or seeing letters either reversed or "flying" around the page.
However, according to a recent (2002) definition of dyslexia (there are more than one, and they have changed over time) from the International Dyslexia Association, "Dyslexia is a reading disorder that is neurological 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."
Secondary consequences occur because as children get older and move through grade school, teachers rely more and more on written material for teaching. A 4th grader might learn about photosynthesis first by reading about it in a text book, rather than having the teacher teach it verbally or with visual cues first.
So instead of referring to dyslexia as a problem of visual processing, the focus is now on auditory processing, specifically phonological processing.
What, then, is phonological processing? Phonological processing is the awareness (usually unconscious at first) that words are made up of discrete sounds. The word "hat", for example, is made up of three sounds: h, short a, and t.
While spoken language is acquired quite naturally by most children, written language is not. Most children do not have to be taught how to speak. Reading, on the other hand, is not a normal developmental skill. It must be taught. If we think about the child who is learning language, but is not particularly strong in the area of phonological processing, it is not a great leap to see why these children may have difficulty learning how to read. When you read, you have to associate a sound with a symbol. Then, you have to blend those sounds together to make a word and, in addition, you have to begin to remember that specific sequences of letter-sounds always make specific words. Finally, you need to associate meanings with the words, be able to understand them when juxtaposed to other words, and easily understand combinations of words as they appear in sentences, paragraphs and books.
In 1996, a very interesting article appeared in Scientific American, by Dr. Sally Shaywitz. Dr. Shaywitz is a pediatrician, co-director of the Yale Center for the Study of Learning and Attention, and professor of pediatrics at the Yale University School of Medicine. In the article, she describes phonological processing as a "lower order linguistic function" and then describes, in detail, how difficulties with this processing blocks higher order linguistic functions and makes it impossible to derive meaning from text.
Essentially, her point is that if the student is unable to process the speech sounds that make up words, then that student will not be able to comprehend and learn from written material. Dr. Shaywitz describes this process quite elegantly; for those who would like to read her article completely, it may be found here:
A recent study was performed by Dr. Anne-Lise Giraud and Frank Ramus from the Ecole Normale Superieure in Paris, France. They reported that dyslexic children exhibit three primary symptoms associated with the diagnosis of dyslexia: 1. difficulty attending to individual speech sounds, 2. difficulty repeating nonsense words or numbers, and 3. a slower than typical rate when naming a series of pictures, colors or numbers, when told to go as quickly as possible.
They also noted differences in the left auditory cortex of the brains of the dyslexics who were studied. They concluded that, "Taken together, our data suggest that the auditory cortex of dyslexic individuals is less fine-tuned to the specific needs of speech processing."
We would be remiss if we did not take note of the fact that there is still some disagreement as to the definition of dyslexia. There are still those that believe it to be the result of a visual disorder and there are still those that take their children for visual training to remediate reading impairments. Furthermore, we have parents who firmly believe that visual training improved their child's reading skills. Perhaps, for some children, there is a visual component and perhaps, with more sophisticated testing techniques, such as the fMRI, there will be more definitive information about the efficacy of vision training.
We have found that, using our assistive software, KidsVoyager Online, we are able to address literally all areas of linguistic deficit that are associated with dyslexia, from phonological processing to sound blending; from auditory memory to sound-symbol association; from word retrieval to reading fluency. KidsVoyager Online and the Phonic Engine Reading Method can be utilized to address all of these issues.
Where appropriate, we utilize the Orton Gillingham approach (in which we are certified, and for which we have developed a parent-teacher manual) in conjunction with KidsVoyager Online & the Phonic Engine Reading Method. This optimizes the Orton Gillingham approach, as it's delivered via an engaging multisensory/kinesthetic interface.
* Roongpraiwan, R., Ruangdaraganon, N., Visudhiphan, P., et. al. (2002, November). Prevalence and clinical characteristics of dyslexia in primary school students. Journal of the Medical Association of Thailand, 85 (Suppl. 4): S1097-S1103