A century ago Dr Pringle-Morgan, an enquiring school doctor in Sussex, alighted upon a curious case. Percy, a bright 14-year-old, good at games, the son of clever parents who, despite five years of intensive efforts to teach him to read, could not recognise words beyond “the” or “and”.

He wrote his own name as “Precy” and was “quite unable to spell the name of his father’s house though he must have seen it and spelt it scores of times”. Percy possessed keen mathematical ability, but he told the doctor that written words had “no meaning to him”. The boy’s schoolmaster believed “he would be the smartest boy in the school if the instruction were entirely oral”. The good doctor was so convinced that this was a remarkable case of “congenital word blindness” that he submitted an article to the British Medical Journal in 1896, the first published recognition of dyslexia in this country.

Our views about dyslexia have come a long way over the past 100 years, though the image of Percy remains with us as the typical dyslexic: an intelligent if not gifted middle-class boy (three times as many boys as girls are recognised as dyslexic). In the 1990s his inability to read and write comes with a few other embellishments referred to as “specific learning difficulties”, suggesting a range of difficulties, not a single problem. For example, we may picture him as rather dishevelled with trailing shoelaces and a battered, disorganised schoolbag. We may expect him to be clumsy and unco-ordinated (though the real Percy was good at games), caused by poor hand-eye co-ordination. He is likely to have a poor short-term memory - being unable to hold information while processing it. We may expect him to have poor concentration and unusual or eccentric speech patterns but to be good at art and drama.

Figures for the number of dyslexic children in Britain vary wildly though it is generally thought that 4 per cent suffer severe dyslexia and many experts agree a further 6 per cent have milder dyslexic difficulties. Some practitioners, however, believe that up to 20 per cent of children display dyslexic tendencies across the range from very severe to very mild.

Parents of children such as Percy have fought long and hard for dyslexia to become a recognised condition. If you look into the histories of organisations such as the Dyslexia Institute or the British Dyslexia Association you will find key personalities who, like Liz Brooks, the DI’s executive director, or Lindsay Peer, the BDA’s education director, first pitched into the fray because they themselves had dyslexic sons or daughters.

To some extent, the populist perception in the Seventies and Eighties that dyslexia was a middle-class excuse for slow learners worked against dyslexic children being properly provided for. Teachers in the back woods of the profession bridled at what they perceived as a pushy middle-class cover-up for lazy and difficult children, even in the face of professional assessments confirming the child’s condition.

Such opinions still exist, but they are rarer, thanks to the unremitting work of the DI in teaching, assessment and teacher training; in the work of the BDA in supporting parents’ groups, setting up helplines, lobbying and promoting research; and in the work of researchers themselves. Recently, Norwegian scientists have reported finding genes linked with dyslexia on human chromosomes. (See Research Focus in this week’s TES, page 22.) Dyslexia was an officially recognised condition by 1994, included in the Code of Practice on the Identification and Assessment of Special Educational Needs. Despite increasing recognition, it is still not uncommon for many dyslexics to go through primary school without any significant intervention, only receiving a statement of educational need once they reach secondary school. By any measurement this is too late. By then a child’s self-esteem will have been crucially damaged, setting off a chain of other difficulties that may include truanting, disaffection, behavioural disturbance, withdrawal and an overwhelming sense of failure. For decades after Dr Pringle’s article, dyslexia was thought to be a form of word blindness. However, the most widely accepted view today is that dyslexic children’s difficulties are essentially phonological. This means that they have difficulty in reflecting on the sound structure of spoken words and so find it hard to learn how to relate letters to the sounds of written words.

Maggie Snowling, professor of psychology at York University, an eminent authority in the field, was the first in this country to suggest in the late Seventies that dyslexia was a condition caused by problems with phonological coding. Since then she has worked with teams of researchers who have shown through brain imaging studies that the ability to match verbal and visual labelling is produced by connections in the left-hand language regions of the brain and that in dyslexics these connections are poor.

The discovery of genes linked with dyslexia on human chromosomes backs up what researchers and practitioners in the field have long believed, that dyslexia runs in families. Professor Snowling has long been interested in studies on genetically at-risk children, which show that from a very early age, despite appropriate teaching, significant numbers will display language difficulties. She believes that if we are able to pick up very early signs then we can intervene to alleviate problems before they become intractable and complex.

Professor Snowling says: “The fallacy has been that young children with poor reading and writing skills are late developers and will grow out of their problems. However, once they are behind, it is devilishly difficult for dyslexics to catch up.” She believes that early recognition is hampered in many ways by the continuing confusion arising from dyslexia being defined as a range of learning difficulties, including co-ordination and behaviour disorders. “Because the brain is plastic, difficulties in one area are likely to impact on another. But long lists of what can be related under dyslexia are not always helpful,” she says.

In similar vein, new research by the British Psychological Society suggests a sharper definition of dyslexia will not only further early recognition, but aid detection of dyslexia in all children with the condition, regardless of socio-economic background, gender, race and intelligence. In other words, a sharper focus on the condition will also help to get rid of stereotyping and sloppy practice. It is undoubtedly easier to recognise dyslexia in a child who in other ways seems to be making good progress than in one who is generally a slow learner or where there may be lower expectations because of socio-economic background. It is now believed that dyslexia in girls is underdetected, and Percy is no more the type than black children, bi-lingual children or slower learners. Next week is Dyslexia Awareness Week and the BPS Educational and Psychology division has today launched a new definition, pared down to the bare bones, in a report entitled “Dyslexia, Literacy and Psychological Assessment” (see page 2).

The report states: “Dyslexia is evident when accurate and fluent word reading andor spelling develops very incompletely or with great difficulty.” It goes on to say that the problem must be severe and persistent despite appropriate learning opportunities and that this new working definition should provide “the basis for a staged process of assessment through teaching”.

Redefinition has been thought necessary on two counts: the first to get away from “deficit” practice - that is, accepting a child is dyslexic and drawing on extra teaching resources only when their reading age is three or four years behind their intellectual ability; the second is to crystallise its meaning as a condition that can affect all children: black and white; English and multi-lingual speakers; rich and poor; highly intelligent and slow learners.

Rea Reason, an educational psychologist and senior lecturer in education at Manchester University, who chaired the report’s working party, says people have become confused about what dyslexia means: “Of course in an individual assessment we can consider other hypotheses such as working memory problems and other syndromes such as clumsiness and disorganisation, but the literal meaning is difficulty with words and that’s what we have to start from.”

She hopes the definition will aid early detection of the condition and is hopeful that the increased knowledge of learning and literacy difficulties in primary schools through the National Literacy Strategy will also prevent unnecessary delays in intervention for learners with persistent problems.