What does it matter whether there really is such a neurological deficit, so long as people who need tuition get tuition? I believe it matters very much, for several reasons. Firstly, much thinking about dyslexia is almost wilfully sloppy and sloppy science never did anyone any good, very particularly the subjects of it. Many appear willing to make the diagnosis, rather fewer are qualified so to do. (We are, after all, discussing neuropathology here!) Many diagnoses stand on small, highly controversial and rather subjectively assessed, evidence. And then, people given a diagnosis of a neurological deficit may find such a label at the least disconcerting, at worst devastating. (‘That was another big shock, finding out you're disabled!’ cried one student. [Whitehouse 1995 p. 21]) And then, what about those who don't achieve the label? Are they simply (and publicly) to be designated as stupid? And then, we don't appear able to see over or around dyslexia; once the diagnosis has been invoked we seek no other explanations for presenting phenomena. Simpler alternative, much more everyday, scientifically duller, less sexy (and much less lucrative) explanations are very much less assiduously sought once a diagnosis of ‘dyslexia’ has been made. And finally, and crucially, in the face of such a diagnosis we appear to act differently - we seem to see a need for deficit-focussed, repetitive, tightly controlled and limited practice (e.g. Lee 2002), and we seem abruptly to experience considerably depressed expectations (Kerr 2001 a & b and see notes to this chapter). Suddenly we are content with poorer results - slower and less accurate outcomes more laboriously produced. We may become more sympathetic, but we also become less demanding. We aim lower. We teach mechanics and detail rather than purpose and flair, rules rather than writing. This is inevitable once we have attributed a student's problems to a single, conceptually simple (albeit imperfectly understood), innate and unalterable cause. This is classic soil in which to grow learned helplessness - and assuredly not only in the student.
Perhaps we should step back and think about what it is, and isn’t, that we are actually discussing. Dyslexia raises hackles and passions. People, as you may already have begun to suspect, become highly partisan. Blood pressures, as you may have observed, rise. Tempers easily fray. It behoves me, therefore, to make precisely clear what I am saying and, probably even more importantly, what I am not saying. For reasons which will become clear, I believe dyslexia is very important, a deadly serious problem, albeit a virtual one.
Firstly, what do I mean by dyslexia? There are two kinds of dyslexia – acquired and developmental. (Developmental dyslexia is what everyone really means when they simply say ‘dyslexia’, a habit I shall maintain here.)
Acquired dyslexia is rare, at least in ‘pure’ form. It is thoroughly unpleasant, but perfectly understandable in terms of cognitive psychology and so is not scientifically controversial. Acquired dyslexia is the result of trauma to the brain occurring after literacy has been learned by it. Some accident (a blow to the head, or perhaps a stroke) results in damage to the part of the brain which had learned literacy skills. Depending on the degree of damage, the skills will be correspondingly lost. The same applies to speech, of course. Many stroke victims have their speech centres damaged and show varying degrees of loss of the power of speech. This is horrible but makes perfect cognitive sense – if you damage the part of the brain which has learned to be responsible for such and such a skill then that skill will be correspondingly damaged. How could it be otherwise?
Developmental dyslexia is an utterly different animal. Here, there is assumed to be an innate neurological deficit of some kind. (If there is no neurological deficit behind dyslexia it is, of course, simply a surprising difficulty with literacy, not a ‘dys’ at all, and back to square one we must all go.) In developmental dyslexia the neurological deficit is presumed to be innate, or pre-wired - to have been present since conception or at least since birth. Some claim that the deficit is written into the genes (eg Cardon et al 1994, Fisher et al 1999, Olson 2004) but others claim that the deficit is the result of damage to the foetus during gestation, for example biochemical trauma in utero (eg Geschwind and Galaburda 1987). At any rate, developmental dyslexia is presumed to be a defect or affliction, present from birth or the very earliest childhood, of those parts of the brain which will one day, when the time comes, be expected to learn the skills of literacy. It is, in this view, an innate defect, irremediably hard wired into the brain which is innately pre-wired to learn literacy only in a particular location or locations. These ideas are, biologically speaking, extraordinarily unlikely, as we shall see later. They are also peculiarly pessimistic.
Secondly, what inferences may righteously be taken from a stance of scepticism towards this neurological deficit explanation for surprising difficulty with literacy? One inference that may not properly be taken is that the holder of a sceptical opinion towards dyslexia is also sceptical that there are large numbers of people with literacy difficulties. Clearly, and to the certain knowledge of this author, there are many such, and equally clearly many experience rather peculiar difficulties. To doubt that there is a neurological fault in their brains is not the same as denying that they have a problem. Further, and by exactly the same token, the inference that a dyslexia sceptic must think that special educational provision is unnecessary for people with such a surprising difficulty with literacy may also not properly be made. Clearly, people with special difficulties need particular assistance; they should better, perhaps, have practical help without a diagnosis of an incomprehensible, improbable and everlasting neurological defect having to be ‘diagnosed’ first.