Intervention for mixed-up minds

Dyslexia was first described in the British Medical Journal more than a century ago, when W. Pringle-Morgan set out the case of Percy, a 14-year-old boy of good intelligence who could not read. Starting with Percy, Sally Shaywitz's book brings the reader rapidly up to date via an excellent review of the nature, causes and treatments of reading problems, interwoven with illustrative case histories of people with dyslexia.

First Shaywitz provides a context within which to understand dyslexia, by laying out the findings of the Connecticut Longitudinal Study, which followed the progress of more than 400 children during their period of reading acquisition. One in five had reading problems but only a third were receiving any intervention, and it was observed that dyslexia was under-identified in girls. These findings are worrying, especially as the gap between children with dyslexia and their peers widens with age if appropriate intervention is not in place.

The cognitive theory of dyslexia that Shaywitz espouses is well accepted.

In her view, the core weakness lies in the part of the language system that processes speech sounds. Phonological processing difficulties are seen from an early age in children with dyslexia, who may be slow to speak, get words muddled, and later have word-finding difficulties, especially under time pressure. But children with dyslexia do not have problems with the meanings of words, grammar or communication. According to Shaywitz, their failure to learn to read is a consequence of their language profile. Learning to decode print depends upon being able to reflect on the sound structure of spoken words (phonological awareness), and this is a skill that escapes children with dyslexia, at least until some years after the age at which it is usually acquired.

Shaywitz moves on to discuss the brain basis of dyslexia, as revealed by brain-imaging studies. In simple terms, she describes three main brain circuits connecting posterior visual areas with language regions at the back and front of the brain. According to this theory, skilled readers primarily make use of a posterior occipito-temporal reading system involving the "word form" area, whereas less accomplished readers rely on a slower more analytical pathway through the parieto-temporal cortex. This latter pathway shows under-activation in dyslexic readers (considered to be the "neural signature" of dyslexia), and it is thought that they compensate by relying on alternative circuitry. On an optimistic note, Shaywitz reminds us that intervention, especially if given early, can be very effective. Indeed, she goes further, to suggest it can repair the brain and restore normal function in left-hemisphere reading systems.

The remainder of the book is practical in orientation, packed with principles of good practice for the assessment and management of reading problems. The section on diagnosing dyslexia begins with a discussion of the early signs and provides checklists comprising what reading-related skills to expect at which ages (from three to nine years), and what the tell-tale signs of dyslexia are across the life-span into adulthood. There is also a helpful list of recommendations of diagnostic tests. The message is clear: it is unwise to delay assessment and diagnosis; dyslexia should be identified early to allow appropriate interventions to prevent the downward spiral of low achievement.

The bulk of the book is concerned with the management of reading problems.

Chapters cover how to help a child become a reader, how to help a struggling reader become proficient and how to ensure that people with dyslexia enjoy optimal support and appropriate allowances in their educational and work settings. In these sections, Shaywitz details activities to promote a wide range of reading-related skills in children of different ages and in young adults. She starts with phonological awareness training for rhyme, segmentation and blending skills, and goes on to describe activities that promote letter knowledge, sight word reading, spelling and phonics. She also emphasises the need to move beyond word-level reading skills to encourage reading fluency and comprehension.

Recommendations are accompanied by word lists and advice on what books to read and which materials to use. She also encourages talking to children to ensure they understand their strengths and weaknesses, and she discusses what to look for when selecting a school. On one issue Shaywitz is definite - a child's reading programme needs to be in the hands of an expert: teaching a dyslexic child to read is a skilled process that must make contact with scientific knowledge of the condition and its treatment. The book closes with some notable success stories followed by useful chapter notes, including a bibliography.

Overcoming Dyslexia is an unusual book. It is written by a neuroscientist who is also a practising paediatrician, it is able to make direct links between theory and practice. Shaywitz does this admirably by casting scientific theories in simple terms and providing sound, authoritative and comprehensive management advice. The writing is both objective and emotive and this has an appeal. But there are some noteworthy gaps: the book does not debate the definition of dyslexia, and the cause of the "glitch in [brain] wiring" is not elaborated. But this should not matter to the parents and carers, teachers and practitioners to whom the book is geared (although, a note of caution: this is a text-heavy book with relatively few illustrations).

Of more concern, from the British perspective, is that the book is written with a US audience in mind. Cast against the backdrop of US education policy and the influence of the National Reading Panel's report, it contains jargon that does not translate well - for "public schools" read state schools, for "accommodations" read allowances, for "programs" read reading schemes - and many of the specific recommendations for books and materials are unfamiliar.

In summary, this is an excellent book for the practitioner who wants to be updated on theories of dyslexia with a view to developing good practice.

Such a reader will need to translate the rich content of the reading programme into UK fruits, but this is certainly not impossible, and the web links in the book give useful leads. Parents will find plenty of useful advice, but may be left slightly perplexed by transatlantic differences in terminology and educational practice.

Margaret Snowling is professor of psychology, York University.