Resource Centre: Library

What is Dyslexia?

Harry T. Chasty, B.Sc, M.Sc (Psychology), Ph.D, F.R.S.A,
Consultant in Learning Abilities and Difficulties

Dr Harry Chasty was invited to be Co-ordinator at the 1994 Consultative Conference, Action for Dyslexia, held in Brussels. The Ministries of Education from the then twelve Member States were invited to send delegates. The Conference was chaired by Robin Salter, President of the European Dyslexia Association.
In this article, Dr Chasty defines dyslexia from an anglophone perspective.

Introduction
In 1970, Dr McDonald Critchley, Chairman of the World Federation of Neurologists, defined dyslexia as ‘a disorder manifested by a difficulty in learning to read, despite conventional instruction, adequate intelligence and socio-cultural opportunity, which is dependent upon fundamental cognitive difficulties which are frequently of constitutional character.’

Since then research into this learning difficulty has grown rapidly, tending to concentrate upon the ‘fundamental cognitive difficulties’ which Critchley referred to but did not specify. Those involved in the research process often tend to take a single-minded or rather limited perspective and regard their area of the subject as the key aspect. Parents and practitioners coming fresh to the field should take a broad view, which encompasses all the major aspects of research. This should lead to a more effective understanding of the range of difficulties experienced by dyslexic children, and how these should be managed in forwarding the child’s education.

When talking about dyslexia to parents, I often use the analogy that dyslexia is a funny animal rather like an elephant. When examining it by touch to discover what it is, if we grasp it by the tip of its trunk, the picture we construct in our mind is very different from the picture we might construct if we grasped it by a tusk, a foot or an ear. In constructing the picture of the whole dyslexia ‘animal,’ it is essential to take the broader perspective which includes all the factors identified in the research.

Key elements from the research picture
Early research by Pringle-Morgan, Hinshelwood and Orton looked at the visual and motor/muscle movement deficiencies in the child’s reading. More recently Burt and Schonell, while not using the word dyslexia, wrote about reading ‘backwardness’ related to the deficiencies in these aspects of the child’s learning to read. At present Marion Annett and Georgina Rippon are researching this area of brain function in relation to reading difficulty.

Research into the failure to understand the recurring regularities in the sound patterns of our language, leading to the phonological difficulties experienced by dyslexic readers, is prestigious and popular with the psychological ‘establishment.’ Vellutino, Bryant, Bradley, Frith, Snowling, Hulme and Hatcher are some of the key workers in this area. Hatcher’s phonological training programme, ‘Sound Linkage’ is effective and popular.

Dyslexic children are noticeably forgetful, and this significantly affects their learning and everyday skills. There are three routes through short-term working memory into learning: through hand and motor memory, through eye and visual memory and through ear and auditory or phonological memory. Difficulty in the operation of short-term or working memory systems in dyslexic children has been researched by Alan Baddeley, Sue Gathercole, Graham Hitch and others.

Over some 30 years, neurological research of vital significance has emerged from Harvard Medical School. This work was initiated by Norman Geschwind in the 1960s. Geschwind identified areas of the brain necessary for language specialism which are of great significance in learning to read. He discovered that there were differences in the cerebral asymmetry of individual learners, some of whom did not show the usual left hemisphere specialism for language. This difference in neurological organisation made them less efficient in learning language and reading skills. Under the Orton Dyslexia Society brain research project, these ideas were taken forward by Albert Galaburda, who concluded that in dyslexic learners there was a ‘uniform absence of left-right asymmetry in the language area of the brain.’ The changes he observed were associated with qualitatively different patterns of cell connections forming the ‘architecture’ of the brain. He advised that dyslexics should not be regarded as having a learning difficulty, rather a different kind of learning ability, and he gave some understanding of the creativity often shown by dyslexics. More recently, Rosen and Sherman have refined this work, identifying areas of the brain where different cell structures, leading to inefficiency in learning, are observed in dyslexics.

In Europe, Dirk Bakker also researched the failure of dyslexic learners to establish the normal left-right ‘functional asymmetry’ of the brain. He pointed out that in learning to read, at one stage, right hemisphere visual processing of words as shapes was necessary. At a later stage, the processing of sound symbols in the left hemisphere was necessary. Children who had not developed appropriate ‘functional asymmetry’ may use either right hemisphere visual or left hemisphere verbal/phonological strategies inflexibly and ineffectively in reading. Bakker developed a training programme to facilitate more efficient use of appropriate strategies.

Speed of information processing is also affected. Further work by Livingstone, in association with the Harvard neurological research team, established that the neuro-anatomical abnormalities (nerve-structure) observed in the magnocellular pathway which links the eye to the visual cortex resulted in the dyslexic learner processing slowly presented visual information adequately, but fast visual information significantly less effectively. Tallal showed similar inefficiency was present in the auditory information processing system. Neurological reasons are now apparent for the auditory and visual perceptual difficulties shown by dyslexics and their generally slower speed of working in class.

Parents have always been aware that their dyslexic children experienced difficulties in learning to read that are similar to those they themselves had experienced when they were in school. Dyslexia appeared to be a genetic problem. Research by Lubs highlighted chromosome 6, while later work by Smith indicated chromosome 15 as the problem area. Dyslexia therefore runs in families and is not limited by bounds of class, creed or nationality. It leads to inefficiency in learning in children in all the education systems of the Member States of the European Union. Its educational effects can be made significantly worse by a family’s mobility, resulting in bilingual or multilingual experience and instability in education, which are often necessary facts of life.

Specific learning difficulties/dyslexia are developmental, because the observed nature of the difficulty changes as the child gets older. At the early age of 18 months the child may show difficulties in establishing motor control in walking. At 24 months the onset of speech may be observed to be very slow. At age three years, some clumsiness may still be evident, and difficulty observed in making some speech sounds or in sequencing the sounds into the correct order to pronounce longer multi-syllabic words. At six years the child may show difficulty in recalling and recognising words while reading. When concentrating on word recognition he may have difficulty in retaining the meaning of the story, and so he may have to read it two or three times to obtain the sense that other children achieve at first reading. Naturally in these circumstances the dyslexic child is less likely to read stories for pleasure and does not develop fluency in reading.

The motor difficulties considered earlier may limit control of the pencil in writing and may result in memory difficulties of shapes and sounds leading to weakness in representing words on paper through spelling. The written expression of ideas is often inhibited, restricted and so error prone that it is difficult to understand what is in the child’s mind. The writing of the dyslexic student does not adequately convey the underlying knowledge or thinking, but all too frequently teachers and colleagues tend to judge the dyslexic child by what has been written on paper.

While the ability to recognise words often improves greatly in the later stages of the education process, reading comprehension, written expression and the underlying planning and organisation necessary for successful study may remain as serious difficulties.

The curriculum problems of dyslexic students are not restricted solely to literacy. There may be underlying cognitive difficulties in managing the rather different language of number. Some 70% of dyslexic learners have difficulty with oral and written calculations and mathematical thinking. The work of Steve Chinn in the UK and Mahesh Sharma in the USA has established appropriate teaching procedures using structured multi-sensory methods to enable dyslexics to develop more effective numeracy/mathematical skills.

Dyslexic students are frequently depressed by their failures and self-conscious about their difficulties in class. They may find the classroom a very stressful environment and if they do not receive the consideration and special teaching they need, can become disturbed and show difficulties in behaviour which add to their learning problems.

In describing the developmental effects of dyslexia, there is a risk that an anxious parent may use the descriptions above as a check list, counting the number of factors their child exhibits. It must be stressed that while some children may show all the points discussed above, others will not. Mildly affected students may show only one or two of the difficulties I have referred to but still be coping adequately and efficiently with their school curriculum. There is no simple or easy guide to the severity of a student’s dyslexic difficulties, nor to when a student will experience failure, which is implicit in dyslexia.

It is my opinion that there are different types of dyslexia, auditory-phonological (to do with hearing and sound), visual-motor (to do with sight and movement) and a combination of both. I share the view of many experts that in providing appropriate special help for a dyslexic student, it is vital to take account of the underlying cognitive difficulties which give rise to his special needs.

In 1994 the Department for Education in the UK issued a detailed guide to the assessment and management of special needs, including dyslexia, entitled Code of Practice. Under the heading ‘Specific Learning Difficulties (for example Dyslexia),’ at paragraph 3.60, a very useful description is given:

‘Some children may have significant difficulties in reading, writing, spelling or manipulating numbers, which are not typical of their general level of performance. They may gain skills in some subjects quickly and demonstrate a high level of ability orally, yet may encounter sustained difficulty in gaining literacy or numeracy skills. Such children can become severely frustrated and may also have emotional and/or behavioural difficulties.’

Advice is given at paragraph 3.62(iii) that in identifying the nature of the child’s difficulties, local education authorities should seek evidence of the underlying cognitive difficulties referred to above: ‘clumsiness, significant difficulties in sequencing or visual perception, deficiencies in working memory or significant delays in language functioning.’

This is very close to the description of specific learning difficulties/dyslexia which I offered to the British Dyslexia Association’s ‘Meeting Points’ Conference in 1989, which was later published in a paper entitled ‘Meeting the Challenge of Specific Learning Difficulties’ in Children’s Difficulties in Reading, Writing and Spelling by Pumfrey and Elliott: ‘Specific learning difficulties/dyslexia are organising or learning difficulties which restrict the student’s competencies in information processing, in fine motor control and working memory, so causing limitations in some or all of speech, reading, spelling, writing, essay writing, numeracy and behaviour.’ This definition was accepted as an appropriate base for further research and development by the group representing all Member States, which met as ‘Action for Dyslexia’ at the European Parliament in 1994.

The response must be a full and detailed assessment to enable the identification of the dyslexic student’s abilities and difficulties in learning, his information processing skills in fine motor control, auditory, visual and motor short-term memory, his visual perceptual and phonological capabilities and his attainments in the basic curriculum skills of speech, reading, spelling, writing, numeracy and social and behavioural competencies, so that a full and effective programme can be drafted in an individual plan drawn up for the child and implemented by a specialised, trained teacher.

The 30-minute training video which forms part of this Multimedia Pack aims to increase awareness in parents and teachers of the implications of dyslexia and the actions that need to be taken on behalf of dyslexic children. These are children who can learn and do learn, but learn differently. If the dyslexic child does not learn the way you teach, can you teach him the way he learns? Can you then develop his learning competencies to help him find the way to appropriately effective literacy and numeracy skills, so that this child is enabled to make his full contribution to the welfare of the nation and the European Union as a whole?