This reading disorder model emphasises the language processing defects instead of issues via the visual system. This article helps to explain why some intelligent people have so much trouble when learning to read. Dyslexia is by no means a new condition. In fact, the first recorded description of developmental dyslexia was written about in November of 1896 by a Sussex-based Doctor, W. Pringle Morgan, describing a 14-year-old boy’s difficulty with reading despite otherwise appearing bright and intelligent, and research has continued since then.
This article examines the work of myself and several colleagues at Yale Center for the Study of Learning and Attention, during which time we studied and evaluated many children and even more men and women to find reading disabilities. One particular participant, a student of medicine, called Gregory, found himself diagnosed in grade school as Dyslexic. He discovered he had trouble with pronouncing longer words or more novel terms %28such as the labels that used with anatomic descriptions%29 as well as rote memorization, though he excelled at comprehending complex information such as mechanisms of disease and physiological systems. This difficulty is a classic type of Dyslexia; an unexpected difficulty when learning to read despite their intelligence, education and motivation.
Since the first description of Dyslexia, the concept of what the learning disability is has come a long way. In fact, from the past twenty years, an entirely coherent dyslexia model has developed that focuses on phonological processing. The phonological model works both with the more clinical symptoms of dyslexia and also with what neuroscientists know about the way the brain organises and functions. Various studies over the years including those at Yale, both cognitive and neurobiological, have further refined this model over the past decade.
Over the years, researchers have broken down the models of language into a more simple hierarchy. At the top levels are the components that are involved with syntax and discourse; semantics. At the bottom rung of this hierarchy is where the phonological module lives, which processes the sound elements of language. For example, the word “cat” consists of three different phonemes made up into the full word: “kuh,” “aah,” and “tuh.”
Before any of these words are stored and spoken, they have to be broken down into phonetic units used by the brain module that is phonological. Whereas speaking is a more ‘automatic’ function, reading is a learned skill; the reader must develop an awareness of how the letters on each page represent the sounds of the words themselves.
Words must be segmented into the phonological elements that are underlying, and then those words can be understood. With dyslexia, this system isn’t quite as effective; a less efficient module working with phonology leads the person to representations that are harder to read. By using fMRI technology, we can also see that in both men and women there is a particular brain location used when reading; allowing for further study into the neurobiological effects of conditions such as Dyslexia.
In studying participants with Dyslexia, we can see that while those with the disability may have trouble with memorising long lists or reading complexities, they also have a significant advantage over nondyslexics. These benefits are often in their ability to reason and conceptualise and that this deficit masks what are often excellent comprehension skills that can be utilised in alternative ways.