(In the interest of keeping some of the things of done on education together under one blog, I’ll ocassionally reprint something done elsewhere. This is one of those pieces, originally published as two separate posts on June 3rd and 4th, 2008…)
That is the ten thousand dollar question…
I recently participated in a discussion on the International Reading Association’s listserv for teachers, a discussion in which the exact definition of dyslexia featured prominently. As a backdrop to that discussion, let me show you what I found when I went looking for a definition online.
- Speakability, a UK-based support group for people with aphasia, defines dyslexia simply as “difficulty reading.”
- The Communications Forum, another UK-based support group for people with communications disorders, dresses their definition up with a few details: “Difficulty with written language. Dyslexia affects reading, spelling, writing, memory and concentration. Sometimes called a specific learning difficulty. Dyslexia can be developmental or acquired.”
- Shannon Booth, a neuroscience major at a college in Minnesota, has a definition online that seems simplistic to me, but reflects common perceptions: “A disorder where things are done or read backwards. For example, a “d” and a “b” might be confused.”
- inURarea, a UK-based childcare group, expands the definition slightly to exclude some reading problems based on “sensory defect” and specify that it is a neurological condition: “Difficulty in reading due to a defect of brain function other than sensory defect.”
- The Nebraska Department of Education says dyslexia is “a developmental reading disability, presumably congenital and perhaps hereditary, that may vary in degree from mild to severe.”
- Child Care Aware defines dyslexia as “an impairment in the brain’s processing of information that results in difficulty reading, spelling, writing, and related language skills.”
- One high school science teacher says that dyslexia is an “impairment in the visual cortex that leads to difficulty in learning to read, write, or spell.”
You can probably guess from those seven examples that definitions of dyslexia are spread out along a continuum ranging from the simple two word “reading difficulty” to formulas that are tediously long and complicated. They also range from vague generalities (half the people I know have difficulty reading) to somewhat more specific ideas (like being congenital and hereditary) and the nature and location of the disorder.
The term “dyslexia” was coined by an eye doctor in Stuttgart, Germany, in 1881. While the scientific community has been tinkering with the condition for over 125 years, most of the definitions during the first hundred years are best described as “exclusionary.” That is to say that a doctor or therapist would exclude causes for poor reading (is it poor eyesight?…no; is it low IQ?…no; is it a hearing problem?… no; is it lack of access to education?…no), and when the doctor ran out of other choices, the reading problem was determined to be dyslexia. Theories existed about what caused dyslexia, or how dyslexia worked to cause the problems seen in a patient; but the technology to test those theories, to observe brain function, didn’t exist until recently.
The growth of linguistics led to new ideas about dyslexia in the 1970’s – ideas that revolved about brain function and the processing of the sounds in a language. Phonemic awareness has become one focus of research into dyslexia. If children had some problem identifying the psychological sound units of their language, associating those sounds with symbols (letters) would obviously present problems – and reading would be affected.
The development of neuroimaging in the 1980’s and 90’s has further served to promote research into dyslexia. It is now possible to observe some aspect of brain function in a living person without invasive techniques like surgery. And far more data on brain function can be obtained than was possible in the past.
Below you will find a few of the more popular, formal definitions for dyslexia:
- According to the British Dyslexia Association dyslexia is “a combination of abilities and difficulties that affect the learning process in one or more of reading, spelling, writing. Accompanying weaknesses may be identified in areas of speed of processing, short-term memory, sequencing and organisation, auditory and/or visual perception, spoken language and motor skills. It is particularly related to mastering and using written language, which may include alphabetic, numeric and musical notation.”
- The National Institute of Neurological Disorders and Strokes says that dyslexia is “a brain-based type of learning disability that specifically impairs a person’s ability to read. These individuals typically read at levels significantly lower than expected despite having normal intelligence. Although the disorder varies from person to person, common characteristics among people with dyslexia are difficulty with phonological processing (the manipulation of sounds) and/or rapid visual-verbal responding.
- The International Dyslexia Association says that dyslexia “is a language-based learning disability. Dyslexia refers to a cluster of symptoms, which result in people having difficulties with specific language skills, particularly reading. Students with dyslexia usually experience difficulties with other language skills such as spelling, writing, and pronouncing words. Dyslexia affects individuals throughout their lives; however, its impact can change at different stages in a person’s life. It is referred to as a learning disability because dyslexia can make it very difficult for a student to succeed academically in the typical instructional environment, and in its more severe forms, will qualify a student for special education, special accommodations, or extra support services.”
The definitions have some common threads. The IDA’s definition seems gear toward asserting the legal status of dyslexia as a educational disability. All three definitions are broad and general. And none are particularly clinical in the sense of providing much criteria for testing or for distinguishing people who have some of the symptoms but are not dyslexics from people who are dyslexics.
So now I’ll return to my conversation recently on the International Reading Association’s listserv for reading teachers. Hugo Kerr put forward a proposed definition for dyslexia as part of that discussion. I think the definition comes from his new book, but I haven’t finished it yet. Hugo’s definition is
An innate, neurological condition specifically disabling the acquisition and use of literacy.
You can find it here in a post he wrote to the Reading Teachers list, hosted by the International Reading Association. (You can read posts from the larger discussion here, in the archives of that listserv on the IRA’s site.)
If you contrast Hugo’s definition to the three put forth at the beginning of Part II here, it has some advantages and disadvantages. On the one hand, it is more concise, more portable than any of the three definitions we started this piece with. The phrase “the acquisition and use of literacy” keeps us from having to specify particular problem areas and covers things that might be involved in literacy even though research hasn’t discovered them yet.
Two words make the definition difficult to deal with. The first is innate. I’m not sure it’s clear to us what is and what is not innate in humans yet. I know what the word means. I just don’t know how we measure it. How do we determine whether a particular behavior is innate – especially if it is a behavior that emerges after birth during some developmental stage.
The second problem word for me is specifically. From discussions with Hugo on the listserv, he seems to me to feel that the problems commonly called dyslexia will eventually be attributed to disorders that don’t primarily have to do with literacy. Hugo doubts that we’ll ever identify a neurological disorder that specifically affects literacy. In fact, he has said repeatedly that he doesn’t believe in dyslexia (for example here, in the listserv post from the IRA’s site).
So why write a definition for something you don’t believe in? My conclusion is that Hugo’s definition is so narrow in order to define dyslexia out of existence. The definition is in itself a tool for helping to promote the idea that dyslexia doesn’t really exist.
Does dyslexia exist? I’m not sure. I do know that it is a persistent concept. Over a century of work on the idea hasn’t killed it yet. And I know that brain science is a relatively young field in light of the explosion of technology in the last 25 years.
As someone who provides reading interventions in an elementary school, my primary concern is with what prevents reading. Whether reading failure is the primary cause of some brain problem or is more secondary, the growing importance of literacy in our society probably makes literacy the most important area of impact.
One of the most common complaints about dyslexia research is that the definition is so poor. How do we know what we’re testing for in an experiment? Hugo is among those who complain about that problem. Shoddy research: that’s the accusation. The difficulty with that is that with the advances that have taken place in technology (and therefore in the types of data we can collect) we don’t seem to be sure what we’re looking for at the moment. The research is exploratory, and hopefully well soon know enough to design better research. That’s how science works.
One thing that will not happen: we will never arrive at some final conclusion about dyslexia, one that allows us to simply say, “so there you have it.” That’s not how science works.
Want to know exactly what dyslexia is? Ask me again in 10 or 15 years…
I was looking at a blog post by Tracy Rosen this past week at 
