June 2000 Guest Article
Introductory Notes by
Dr Chris Singleton
Chartered Psychologist and Senior Lecturer in Educational Psychology
University of Hull
Dyslexia is typically characterised by 'an unusual balance of skills'. Dyslexia is a syndrome: a collection of associated characteristics that vary in degree and from person to person. These characteristics encompass not only distinctive clusters of problems but sometimes also distinctive talents. The syndrome of dyslexia is now widely recognised as being a specific learning disability of neurological origin that does not imply low intelligence or poor educational potential, and which is independent of race and social background.
Although dyslexia seems to be more prevalent amongst males than females, the exact ratio is unknown: the most commonly quoted figures are between 3:1 and 5:1. The evidence suggests that in at least two-thirds of cases, dyslexia has a genetic cause, but in some cases birth difficulties may play an aetiological role.
Dyslexia may overlap with related conditions such as dyspraxia, attention-deficit disorder (with or without hyperactivity) and dysphasia. In childhood, its effects can be mis-attributed to emotional or behavioural disorder. By adulthood, many dyslexics will have developed sophisticated compensating strategies that may mask their difficulties.
The majority of experts concur that about 4% of the population are affected to a significant extent. This figure is based on the incidence of pupils who have received normal schooling and who do not have significant emotional, social or medical aetiology, but whose literacy development by the end of the primary school is more than 2 years behind levels which would be expected on the basis of chronological age and intelligence. However, perhaps as many as a further 6% of the population may be more mildly affected (e.g. in spelling).
The neurological bases of dyslexia are now well established and reflected in current definitions of the condition. For example, the International Dyslexia Association (formerly the Orton Dyslexia Society) published the following definition of dyslexia:
"Dyslexia is a neurologically-based, often familial disorder which interferes with the acquisition of language. Varying the degrees of severity, it is manifested by difficulties in receptive and expressive language, including phonological processing, in reading, writing, spelling, handwriting and sometimes arithmetic. Dyslexia is not the result of lack of motivation, sensory impairment, inadequate instructional or environmental opportunities, but may occur together with these conditions. Although dyslexia is life-long, individuals with dyslexia frequently respond successfully to timely and appropriate intervention" (Orton Dyslexia Society, 1994).
The Research Committee of the International Dyslexia Association also produced the following definition of dyslexia, couched in more scientific terminology:
"Dyslexia is one of several distinct learning disabilities. It is a specific language-based disorder of constitutional origin characterised by difficulties in single-word decoding, usually reflecting insufficient phonological processing abilities. These difficulties in single word decoding are often unexpected in relation to age and other cognitive and academic abilities: they are not the result of generalised developmental disability or sensory impairment. Dyslexia is manifest by variable difficulty with different forms of language, often including, in addition to problems of reading, a conspicuous problem with acquiring proficiency in writing and spelling." (Orton Dyslexia Society, 1994)
The British Dyslexia Association has also published a definition of dyslexia that reflects the neurological bases of the condition:
"Dyslexia is a complex neurological condition which is constitutional in origin. The symptoms may affect many areas of learning and function, and may be described as a specific difficulty in reading, spelling and written language." (British Dyslexia Association, 1995).
The biology of dyslexia has been investigated in a range of studies that have confirmed a difference in brain anatomy, organisation and functioning. The latest brain imaging techniques, as well as encephalographic recording of the electrical activity of the brain, and even post-mortem examination, all reveal a range of functional and structural cerebral anomalies of persons with dyslexia.
Although dyslexia is legally recognised as a 'disability', it is not a 'disease' nor can it be 'cured'. Indeed, the neurological differences found in dyslexia may confer advantages for some individuals (e.g. in visual or perceptual skills), which may to some extent explain the apparent paradox that some individuals who have problems with elementary skills such as reading and writing can nevertheless be highly gifted in other areas.
The deficit model of dyslexia is now steadily giving way to one in which dyslexia is increasingly recognised as a difference in cognition and learning.
Although most definitions of dyslexia found in the scientific and educational literature take this 'neurological approach', not all do. For example, the British Psychological Society's Working Group on 'Dyslexia, Literacy and Psychological Assessment' published the following working definition:
'Dyslexia is evident when accurate and fluent word reading and/or spelling develops very incompletely or with great difficulty.' (BPS, 1999).
This focuses on literacy learning at the 'word level' and implies that the problem is severe and persistent despite appropriate learning opportunities. The authors believe that this definition provides the basis for a staged process of assessment through teaching (see later under 'Identifying children with dyslexia'). It must be pointed out that this definition has been criticised by several authorities on various grounds, including being too wide.
Dyslexia is a variable condition and not all people with dyslexia will display the same range of difficulties or characteristics. Nevertheless, the following characteristics have been widely noted in connection with dyslexia.
Reading and perceptual difficulties
These can include:
These can include:
Further important factors in dyslexia include the following:
The conventional approach
Conventional methods for diagnosing dyslexia in the child who is failing in literacy development have remained largely unchanged for the past 30 years. Essentially, these involve establishing that:
The first three of these points comprise the discrepancy criterion and the exclusionary criterion. Together, these imply that dyslexia can only be identified when there is a significant discrepancy between intelligence and attainment and when all other potential causes of reading disability are excluded. Unfortunately, this has unwittingly had the effect of making dyslexia a condition observed mainly in bright, middle-class children, which has in turn given cause for some professional disparagement of the condition over many years. It also results in diagnosis being delayed until a 'significant' discrepancy between intelligence and attainment can be demonstrated. In some areas, resourcing policy may force educators and psychologist to ignore a child's problem until that child has slipped below some arbitrary threshold (e.g. two years behind expected literacy skill level). Despite the fact that the child may clearly be falling progressively behind, remediation is not offered until the predetermined threshold is exceeded, with the explanation being given to the parents to the effect that their child's difficulties are not serious enough at the moment for help to be provided.
There are many children with reading difficulties who do not satisfy these criteria (e.g. they may also come from disadvantaged home backgrounds and/or have emotional problems) and yet may nevertheless have some brain anomaly. In such cases, however, we would be unable to give a proper diagnosis were we to rely upon traditional diagnostic criteria. It is clear, therefore, that we have to move to a much more satisfactory definition and more reliable diagnostic criteria if we are to be able to identify dyslexics accurately.
It has long been believed that sub-test profiles of individual intelligence scales can reveal the cognitive deficits of dyslexics, although the subject has not been without its controversies. In the so-called 'ACID profile' on the WISC-R (Wechsler Intelligence Scale for Children, Revised) the letters A-C-I-D refer to those sub-tests which are often found to be depressed in the dyslexic, i.e. Arithmetic, Coding, Information and Digit span. However, the ACID profile is not a reliable or unique identifier of dyslexia and recent inquiries have tended to reject it (see the BPS report 'Dyslexia, Literacy and Psychological Assessment', 1999).
The disadvantages of conventional assessment and diagnostic procedures may therefore be summarised as follows:
Developmental precursors of dyslexia
At the pre-school stage many dyslexic children are already showing early signs of their disorder. The key is usually an uneven developmental profile, particularly in cases where there is a family history of speech or literacy difficulties, or where there is evidence of significant birth difficulties. Characteristic difficulties include one or more of the following:
The emphasis here is on detecting an uneven developmental profile where there is no evidence of primary medical, social or emotional causes for the child's difficulties. A similar approach needs to be taken on school entry. The dyslexic child will usually be distinguished from children with general developmental delay by obvious abilities in other areas. A typical case would be the child who, at 5 years of age, appears bright, alert and who is able to converse intelligently but who nevertheless is unable to write his or her own name, copy simple letters or shapes, or cope with fine motor tasks. Alternatively, the child may be able to copy and draw well for his or her age, show skills in construction and modelling, but be unable to repeat a short sequence of digits, have difficulty in learning nursery rhymes and have relatively immature language development.
These are characteristic types of dyslexic children that could often be identified much earlier than is typically the case at present. Unfortunately, there are no generally accepted objective procedures for identifying such children at an early age. Thus, even if a teacher is alert to these early signs and symptoms, this will still usually be insufficient to provide a case for specialist help for the dyslexic child. Education authorities require more objective evidence in order to make special provision. There is therefore a need for formal assessment procedures that are not inordinately costly or time consuming but which are sufficiently reliable to justify taking action.
Cognitive precursors of dyslexia
There is substantial evidence that both phonological processing and short-term memory are important factors in dyslexia. It is now well-established that phonological processing ability is very closely related to reading development. Children who, when they start school, show good phonological awareness (i.e. are aware of syllables and can detect rhyme and alliteration) are the ones who are most likely to make good progress in learning to read. On the other hand, children with difficulty in carrying out these types of phonological tasks when they begin school are the ones who are most likely to have difficulties with learning to read even though they may overcome their difficulties with speech sounds as such. In general, it is argued (a) that phonological processes underpin the development of a phonological decoding strategy in reading, and (b) that working memory plays a significant role in this strategy, enabling constituent sounds and/or phonological codes to be held in short-term store until these can be recognised as a word and its meaning accessed in long-term memory. Dyslexics, who tend to have weaknesses in phonological processing and short-term memory, will thus tend to have
Whilst researchers have generally agreed on the importance of the roles of phonological processes and memory in dyslexia, for some years the issue of subtypes of dyslexia has been the subject of controversy. Many discussions in the literature refer to two broad subtypes: auditory dyslexia and visual dyslexia. The visual dyslexic tends to have problems with visual discrimination, visual memory, visual sequencing, left-right scanning and in rapid visual recognition of words. The auditory dyslexic tends to have problems with discriminating speech sounds, in sound blending, auditory sequencing and serial memory, and in phonological awareness. In a classic study, Boder (1973) reported that 63% of her dyslexic sample could be described as auditory dyslexics, while only 9% fell into visual dyslexia category, leaving about 22% with mixed difficulties (both visual and auditory problems), and 6% of her sample undetermined.
Psychological research on acquired dyslexia (i.e. the condition of impairment in literacy skills in adults as a result of a stroke or other neurological damage) has tended to confirm the existence of two broad sub-types. These involve (a) patients displaying difficulties with whole-word reading (variously referred to as 'surface dyslexia', 'morphographic dyslexia', or simply 'visual dyslexia'), and (b) patients displaying difficulties with phonological processing and non-word reading (variously referred to as 'deep dyslexia', phonographic dyslexia', or simply 'auditory dyslexia'). The question arises whether the same (or similar) subtypes also exist in developmental dyslexia, which would have important implications for assessment and teaching. However, research knowledge in this area is still sketchy and the concept of subtypes of developmental dyslexia remains in professional and academic dispute.
The value and validity of early identification of dyslexia
Without early identification procedures the teacher may easily assume that the child is lazy or simply requires more time for reading skills to develop. When children are diagnosed as dyslexic late in the school career, a typical complaint made by parents is that they felt there was something wrong from their child's earliest years at school. However, when the parents expressed these misgivings to the teacher, the response was often: 'Don't worry, s/he will pick it (i.e. literacy) up in time'. In these particular cases the child did not 'pick it up' and consequently required specialist remediation some years later after the problem was eventually diagnosed. By this time the child will often have lost motivation and even become difficult or disruptive in class. This state of affairs is often the focus of strong parental resentment and dissatisfaction with the education system.
The cognitive precursors of dyslexia, summarised above, can be assessed in young children before beginning to learn to read. In the particular case of the dyslexic the value of early identification is enormous. Instead of waiting several years for children to fail, with all the misery and frustration which that inevitably entails, and only then trying to remediate, proper educational provision for these children can be made right from the start. There is good evidence that when diagnosis of dyslexia was made early in school most children with dyslexia can be brought up to their normal classroom work, while identification delayed until late in the primary stage resulted in successful progress by less than half the children. If delayed until secondary school the percentage of successful remediation drops to 10-15%.
Dyslexia screening tests available for teachers
The Aston Index and the Bangor Dyslexia Test are screening tests for dyslexia that have both been available for several years. They embody a fairly eclectic but pragmatic approach that reflects the theoretical inclinations of their creators and the research knowledge available at the time of creation. More recent tests that have been developed (i.e. DEST, DST, CoPS and LASS 11-15) adhere more strongly to the current research emphasis on phonological processing and short-term memory as key factors in dyslexia, although DEST and DST also include measures of fine motor skill and postural stability. CoPS and LASS 11-15 are computer-based assessments; for further information on these, see the website www.lucid-research.com
Aston Index (1976; Revised edition, 1982). M Newton and M. Thomson. Cambridge: LDA. [Individually administered; about 7 years to 16 years, now rather out-of-date, but still has some useful subtests, e.g. in memory. Not standardised]
Bangor Dyslexia Test (1983; Second edition, 1997). T.R.Miles. Cambridge: LDA. [Individually administered, several brief subtests that tap 'positive signs' of dyslexia; about 7 years to 18 years. If you are planning to use this test, you are strongly recommended also to obtain the book 'Dyslexia: The pattern of difficulties' by T.R. Miles (London, Collins Educational, 1983), which explains more fully how to use the test. Partly standardised]
CoPS - Cognitive Profiling System (1996/97) C. H. Singleton, K.V. Thomas and Leedale, R.C. Beverley, East Yorks: Lucid Creative Ltd. [Computer software and Teacher's Manual. Range 4 yrs 0 mos to 8 yrs 11 mos. Individually administered. Comprises 9 subtests of memory, phonological awareness and auditory discrimination. Standardised]
Dyslexia Early Screening Test (DEST; 4:6-6:5 yrs) and Dyslexia Screening Test (DST; 6:6-16.5 yrs) (1996) R. Nicolson and A. Fawcett. London: Psychological Corporation. [Each Individually administered, 10 short subtests of phonological skills, memory, reading, spelling, postural stability, etc. Standardised]
LASS 11-15 (1999) J. K. Horne, C. H. Singleton and K.V. Thomas. Beverley, East Yorks: Lucid Creative Ltd. [Computer software and Teacher's Manual. Age range 11 yrs 0 mos - 15 yrs 11 mos. Comprises 8 subtests of memory, reasoning, reading and nonword reading, spelling and phonological processing. Individually administered but can be installed on a network for group administration. Standardised]
Multisensory methods of teaching for children with dyslexia are usually advocated. These integrate visual, aural, tactile and kinaesthetic modalities to consolidate the learning experience. Lessons must be very well structured, sequential and cumulative, on order to all skills and concepts must be thoroughly practised (overlearned) counteract the memory problems of the dyslexic. Content generally needs to concentrate on phonic skills, as these are usually the weakest aspect in dyslexia.
The range of available products and materials for teaching and supporting children with dyslexia is steadily growing. Well-structured phonics-based multisensory teaching is still the fundamental requirement, especially for primary-aged dyslexics, but the approaches are much more flexible and more fun than the older drill methods.
Some recommended teaching methods and resources
'The Bangor Dyslexia Teaching System' by Elaine Miles. 3rd edition, Whurr, 1997. [Excellent strategies for teaching, plus details of accompanying resources]
'Dealing with dyslexia' by Pat Heaton and Patrick Winterson. 2nd edition. Whurr, 1996. [A revised edition of a popular classroom text]
'Teaching reading and spelling to dyslexic children' by Margaret Walton. David Fulton, 1998. [A new compendium of exercises based on sound practice]
'Day-to-day dyslexia in the classroom' by Joy Pollock and Elizabeth Waller. Routledge, 1994. [A very practical guide for teachers]
'Overcoming dyslexia: skills into action' by Hilary Broomfield and Margaret Combley. Whurr, 1997. [A highly practical book using multisensory teaching for dyslexics of all ages]
'The Phonics Handbook' by Sue Lloyd. 2nd edition. Jolly Learning, 1994. [Especially suitable for use with younger children; lots of photocopiable activity sheets. Makes learning fun and not just for dyslexics]
'Sound Linkage: an integrated programme for overcoming reading difficulties' by Peter Hatcher. Whurr, 1994. [Based on the author's own research in Cumbria: a strongly phonological basis to reading development; also includes a system for phonological assessment.]
'Maths for the Dyslexic: a practical guide' by Anne Henderson. David Fulton, 1998. [A new book of practical activities from an international expert on the subject of maths and dyslexia.]
There are many excellent computer programs for learning and support of dyslexic children of all ages now available. The problem is to spot these amongst the hundreds advertised in the educational software catalogues. To assist busy teachers, the British Dyslexia Association produces a series of information packs that contain reviews of recommended software by experts in this field and give details of where these may be obtained and how the software can be used most effectively. The BDA also publishes a range of useful books and other literature on dyslexia, as well as a termly magazine called Dyslexia Contact. For information, contact the British Dyslexia Association, 98 London Road, Reading RG2 5AU. Tel. 0118 966 8271, Fax 0118 966 2677, E-mail: email@example.com
The book 'Dyslexia and Information and Communication Technology' by Anita Keates (Published by David Fulton, 2000) is highly recommended as a guide to using computers to support dyslexic people.
Computer programs for use in schools and at home are available from REM, Great Western House, Langport, Somerset TA10 9YU. Tel. 01458 253636 Fax 01458 253646.
A free copy of the REM catalogue is available on request. E-mail: firstname.lastname@example.org
Many programs can also be tried out by accessing their website: www.r-e-m.co.uk
Advice on computer hardware and software for older dyslexics is available from iANSYST, The White House, 72 Fen Road, Cambridge, CB4 1UN. Tel. 01223 420101, Fax 01223 426644. E-mail: email@example.com
See also their website for further information: www.dyslexic.com
Recommended further reading
'Dyslexia: a hundred years on' by Tim Miles and Elaine Miles. Second edition, Open University Press, 1999. [A well-written, up-to-date and pretty comprehensive review of the field, but with the emphasis on research knowledge rather than teaching approaches.]
'Dyslexia: a practitioner's handbook' by Gavin Reid. Wiley, 1998. [An accessible, up-to-date overview of knowledge, plus a very practical compendium of resources for teachers.]
'Specific Learning Difficulties (Dyslexia): challenges and responses' by Peter Pumfrey and Rea Reason. Routledge, 1991. [At one time this was the authority on evidence regarding research and practice on dyslexia; it is perhaps a little dated now, but still a valuable resource, especially when writing essays or assignments.]
'Dyslexia: biology, cognition and intervention' (Eds. Charles Hulme and Maggie Snowling). Whurr, 1997. [A fairly comprehensive survey of current research, with chapters written by many international experts; excellent for use when preparing essays or assignments, but a bit technical in places.]
'Dyslexia in Children: Multidisciplinary perspectives' (Eds. Angela Fawcett and Rod Nicolson) Harvester Wheatsheaf, 1994. [A little out-of-date now, but contains useful chapters summarising theories and facts in important areas, such as phonological deficit, automaticity, and visual deficits.]
'The Psychological Assessment of Reading' (Eds. John Beech and Chris Singleton) Routledge, 1997. [A compendium of different approaches to assessing reading from both the teacher's and the psychologist's point of view, authored by national experts. Contains an appendix with reviews of many of the tests used in the field.]
'Dyslexia, Literacy and Psychological Assessment' (Report of a Working Party of the Division on Educational and Child Psychology of the British Psychological Society, Chaired by Rea Reason.) British Psychological Society, 1999. [A useful and fairly concise survey of current knowledge, with specific reference to how educational psychologists should be assessing dyslexia. Some of the findings and conclusions of the Working Party are questionable.]
All the above books are available from IPS, either at IPS events, or by mail-order, and from November, 2000 at the IPS Online Bookstore.
© C. H. Singleton, 2000. All rights reserved.
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