Chapter 2:
2.1 Developmental dyslexia was first described in 1886, in the case of a 14 year old boy who was unable to learn to read. A further study in 1917 attributed such difficulties to “congenital wordblindness”. It was not until the 1960s that research moved from the area of medicine into the area of education, with studies into what factors, if any, discriminated between “dyslexic” and “backward readers”.
2.2 Since that time, there has been much debate on what causes dyslexia and how it is manifested in those who are thought to have the condition. However, there has been little agreement on a precise definition.
2.3 The term “dyslexia” has been generally used within medical/biological research and remains the term preferred by the voluntary groups in this field. However, as Nicholson (2001)21 points out, this implies that “there is a single relatively uniform syndrome”. Current research indicates that this is not the case. Educationalists, in particular educational psychologists, preferred the term “specific learning difficulties”, indicating that the person had a deficit in some of the processes of learning, but not all. Within the USA, during the 1980s, the term dyslexia was replaced with the term “reading disability”. The consequence of this was a shift from an analysis of the process of learning, to that of the process of reading.
Current Research Findings
2.4 One of the difficulties in considering the research into various aspects of dyslexia has been that the studies arise from and are driven by the various models adhered to by the researchers. Results have at times been unconnected, or even conflicting, and led to different understandings of the nature of dyslexia.
2.5 Morton and Frith (1995)22, and Frith (1997)23proposed a Causal Modelling Framework, which permitted these theories to be considered within a common framework. The framework below indicates three levels of an individual’s functioning, together with a consideration of relevant environmental factors e.g. language system, social and emotional factors etc:
2.6 The behavioural level deals with the “symptoms” of dyslexia, e.g. poor reading or spelling, difficulty with rhyme etc.
2.7 The cognitive level deals with the processes underlying the observed deficits in performance, e.g. phonological processing, short-term memory deficits, difficulties with automaticity and central processing etc.
2.8 The biological level seeks to identify the processes within the brain, e.g. abnormalities in the cerebellum, and in the magnocellular pathways. It also allows consideration of information coming from genetic research into the underlying genetic mechanisms.
2.9 It would be helpful to consider the most recent research findings under each of these headings.
Behavioural Level
2.10 Research and anecdotal evidence has suggested a number of behaviours that can be observed in people deemed to be dyslexic. These include difficulty with reading and/or spelling, in discriminating between right and left, difficulty in recalling lists of information e.g. days of the week, telephone numbers. Some information may be omitted, or the sequential order may be incorrect. There are difficulties in phonological tasks, with naming and with spoonerisms. Some find the association between letter name and letter sound difficult to acquire. Many mention clumsiness and difficulties in organisation of information and materials.
2.11 These have led to the development of lists of indicators e.g. Bangor Dyslexia Test and materials published on the website of the various voluntary support groups. Although they have contributed to the planning of intervention in the identified areas, they tell us little of the processes that underlie the acquisition of these skills.
Cognitive Level
2.12 Work on these cognitive processes seeks to identify those within-child variables that underlie poor reading skills.
Phonological Skills
2.13 Phonology has to do with the sounds of words within a language. The phonological delay/deficit model attributes a person’s difficulties in acquiring literacy skills to an underlying weakness in their ability to process sounds accurately eg segmenting words into phonemes, difficulties in retaining strings of sounds or letters in their short-term memory, difficulty in organising their accurate recall, and also naming of items etc. (Snowling 198724, 200125, Stanovich 198826) Difficulties in learning the grapheme/phoneme system (matching letter to sound) would also fall within this framework level.
2.14 At the biological level, these difficulties are considered to arise from differences at the level of brain function, with some genetic predisposition (Frith 199727, Elbro et al 1998)28.
2.15 Some of these indicators can be observed in pre-school children.
The most powerful predictors of later reading and writing skills were those requiring phonological awareness, particularly the ability to manipulate phonemes. However, some children displaying these delays go on to acquire good reading skills, and account must be taken of differing rates of maturation, and of the social, emotional and educational environment the children are exposed to (see 2.24). This corresponds to the environmental framework proposed in Frith’s model.
2.16 Other researchers have looked at differences in short-term memory between dyslexic/non-dyslexic subjects, suggesting that these are linked to inefficient phonological coding. (Hulme et al 199529, Stanovich et al 1997)30.
Biological Level
Automaticity
2.17 Nicholson and Fawcett’s work (199031, 199532) suggests that people with dyslexia also have difficulty with the automatisation of skills. It is known that the cerebellum is implicated in any skill becoming an automatic one, and that it also has a role in the acquisition of language.
2.18 Nicholson and Fawcett demonstrated that dyslexic children require significantly more time both to acquire a new skill and for it to become automatic. For example, pupils were given a task requiring them to walk along a line. There was no significant
difference in their performance and that of a control group. However, when they were asked to count backwards at the same time, their balance became much poorer. It was argued that their need to concentrate on the new task required the balance task to be done automatically. Their cerebellar deficit meant that they were unable to do so, causing their balance to deteriorate. In the control group, the ability to balance was more instinctive, allowing them to concentrate fully on the new task.
2.19 In their research, they identified not just phonological difficulties, but also delays/deficits in working memory, speed of processing, motor skills and balance, and in the estimation of time, all of which are connected to cerebellar activity. These deficits can be observed at the behavioural level, and are often reported by parents and teachers.
2.20 Fawcett and Nicholson (2000)33, in a summary of research findings, indicated that, as well as evidence of cerebellar deficit in function, many dyslexic subjects seemed to by-pass the cerebellum to some extent, with increased frontal lobe activity. This suggested to them that dyslexic pupils relied more on conscious strategies, and may use different methods in sequential learning and automatic performance than non-dyslexics. This has implications for intervention strategies.
Visual Processing
2.21 Research continues into the visual processing skills of dyslexicpupils. They note “visual discomfort” as evidenced by eye-strain and headaches. Stein (1992)34notes difficulties in visuo-motor control. Children reported that the letters seemed to move around the page. In fact the children were unable to control the movement of their eyes and fixate on the print Garzia et al 1993)35. Subsequent research has shown that these motion signals arise from the visual magnocellular system, and that for some dyslexics, this is impaired (Stein et al 2000)36. They therefore find it difficult to learn a reliable representation of letters, word segments and whole words (as they appear to move about), making accurate recall problematic.
Genetic Research
2.22 There is growing evidence of a genetic component in dyslexia. Grigorenko (2001)37provides an overview of this research. Many studies indicate that if at least one member of the family has developmental dyslexia, there is a higher than normal probability that other members will also have reading problems. Evidence from studies of twins has shown that at least some proportion of developmental dyslexia has a genetic basis, even if the transmission mechanisms are not yet clear.
Dyslexia in the Early Years
2.23 There is a body of opinion supported by research suggesting that children who are at risk of developing dyslexia can display indicators before they go to school or shortly after they start primary education. Miles and Miles (1984)38investigated the effect of early intervention. They argued that “if dyslexic children are caught early, less time is needed for catching up, while in many cases the children can be helped before frustration sets in”.
2.24 Chasty (1996)39 maintains that schools represent the most critical period for diagnosis. The earlier the diagnosis and the more immediate the help, the less serious the damage to the child. Although the Task Group recognises that the formal diagnosis of dyslexia at an early age would not be appropriate, it is agreed that certain warning signs or difficulties can be observed and responded to long before the diagnosis of dyslexia can be appropriately applied. (See 2.15).
2.25 The Code of Practice (1998) places an emphasis on early identification and support. It clearly states that the school and teacher have statutory duties and responsibilities to identify and assess a child with special educational needs as soon as possible. The Task Group would like to take this opportunity to reiterate the concerns raised in paragraph 1.14 regarding the lack of teacher expertise in the identification and support of pupils with dyslexic tendencies.
2.26 The Group recommends effective early intervention to minimise the risk of children suffering the negative experience of academic failure and associated consequences.
Dyslexia in Different Linguistic Systems
2.27 Research in this field is developing, but it should be noted that not all studies are using the same criteria for definition of dyslexia, making it difficult to compare incidence levels from one language to another. The initial research was with English speaking populations, and English is known to be one of the most orthographically irregular languages. Some of the more orthographically regular languages have a lower incidence reported.
2.28 Grigorenko’s40review of this area of research concludes that dyslexia appears to be independent of race and social background. She maintains that there is now sufficient evidence to say that phonological approaches are universal aspects of the development of literacy in many languages and understanding of the phonological structure of words is an important predictor of reading success in many languages. However, there remains the question of how to diagnose dyslexia in a way that is compatible with the work going on elsewhere.
Discrepancy Model
2.29 Many researchers have adopted the discrepancy model to select dyslexic participants. This is based on the apparent link between intelligence and reading skill, whereby generally more able children learn to read more quickly than less able children.
2.30 By a statistical process known as regression, it is possible to predict a child’s expected reading age, given their chronological age and IQ. This can then be compared with their actual reading age, and the statistical significance of the difference calculated. In practice, where the actual reading age is lower than would be expected, and the difference is statistically significant at the 95% level, the child could be considered to be dyslexic i.e. have a specific learning difficulty with reading.
2.31 In contrast, poor readers are those pupils who have a measurable delay in their reading level (usually more than one standard deviation below the mean for the general population at their age) but where the difference between their expected reading age and actual reading age is not statistically significant i.e. their performance is in line with what could be predicted given their age and IQ.
2.32 This approach has been the subject of considerable criticism. Snowling (2000)41points out that it is open to be over-inclusive. For example, a pupil who does no reading is unlikely to have a reading age in line with their predicted score. However, the discrepancy is just as likely to be as a result of lack of reading experience, as of dyslexia.
2.33 Stanovich (198642, 199143) argues against the use of IQ in the definition of dyslexia. He points out that the verbal skills of poor readers tend to decline as a consequence of their limited reading experience. If this is the case, then their lowered verbal IQ will predict a lower expected reading age, and may not give a statistically significant difference. The discrepancy model may fail to identify these pupils, even though they have real difficulty with reading. Equally, pupils who have learned to read but continue to have significant spelling or writing difficulties will be missed, unless these skills are included in the criteria.
2.34 Snowling (2000)44 recommends that if the discrepancy approach is used, then it should be supplemented by positive diagnostic markers that will allow practitioners to identify children who show early or residual signs of dyslexia that require intervention. They should not rely solely on the extent of the child’s reading problem.
Definitions
2.35 These have ranged widely over the years. To date there remains no universally accepted definition within the UK. The most recent are considered below.
2.36 British Dyslexia Association 199645:
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. One or more of these areas may be affected. Numeracy, notational skills (music), motor function and organisational skills may also be involved. However, it is particularly related to mastering written language, although oral skills may be affected to some degree.
2.37 The BDA considers the syndrome to be neurological and constitutional i.e. within child, rather than an interaction between the child and its learning environment. They consider the difficulties to be specific (i.e. some areas are not affected) but indicate that they can be manifested more widely than in reading alone, reflecting the experience of many parents and teachers. However, there are no objective criteria for positive diagnosis.
2.38 British Psychological Society 199946:
Dyslexia is apparent when accurate and fluent word reading and/or spelling develops very incompletely or with great difficulty. This focuses on literacy learning at the “word level” and implies that the problem is severe and persistent despite appropriate learning opportunities. It provides the basis for a staged process of assessment through teaching.
2.39 The BPS Division of Educational and Child Psychology (DECP) Working Group’s focus was on younger school-aged children. It removes any consideration of cognitive ability, but again lacks objective criteria for identification.
2.40 The advantage of the BPS approach is the emphasis on the child’s access to “appropriate learning opportunities”. It moves from being a condition within the child, to an interaction between the child and its learning environment. Reason (2001)47 elaborates on the background to this work, and its implications for learning and assessment. There is the expectation that the teaching programme will be adjusted regularly on the basis of the child’s response to instruction. Diagnostic assessment can and should be carried out by the child’s teachers at Stages 1 and 2 of the Code of Practice, facilitating early intervention, without the need to wait for an external assessment from psychologists at Stage 3.
2.41 However, this definition has been criticised as too narrow by Nicholson (2001)48. He argues that most dyslexic children do eventually learn to read. They still continue to have dyslexia, however. Practitioners and in particular teachers of these pupils maintain that their difficulties are much further reaching than just at the word level, and would argue that account needs to be taken of their difficulties in recall, short-term memory, poor organisational skills etc. This too would need to be assessed and included in any learning plan for it to be effective.
2.42 The definition is also of limited use to those wishing to consider identification and early intervention with pre-school children, or with adult dyslexics who have achieved reading but continue to have considerable difficulty with literacy and numeracy tasks, study skills, organisational skills etc.
2.43 The Code of Practice on the Identification and Assessment of Special Educational Needs (1998)49:
The Code of Practice uses both “dyslexia” and “specific learning difficulties” and defines the condition through a number of indicators:
Some children may have significant difficulties in reading, writing, spelling or manipulating numbers, which is not typical of their general level of performance, especially in other areas of the curriculum. They may gain some 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.
2.44 To determine whether the pupil’s needs are significant and complex, the Code then suggests that evidence be sought from the school, asking whether, for example, there are
· significant discrepancies between attainments in different programmes of study, or within the same programme
· expectations of the child which are significantly above their attainments in reading, spelling or mathematics
· evidence of clumsiness, sequencing difficulties, visual perceptual difficulties
· evidence of behavioural difficulties
This implies both the use of indicators, such as those outlined by the BDA in their published materials, and the use of a discrepancy model.
2.45 Many practitioners within Northern Ireland prefer a definition that is broader than that of the BPS, permitting consideration of a wider range of factors than difficulties at the word level.
2.46 Republic of Ireland Task Force on Dyslexia50:
This group proposes the following definition of dyslexia:
Dyslexia is manifested in a continuum of specific learning difficulties related to the acquisition of basic skills in reading, spelling, writing and/or number, such difficulties being unexpected in relation to an individual’s other abilities. Dyslexia can be characterised at the neurological, cognitive and behavioural levels. It is typically described by inefficient information processing, including difficulties in phonological processing, working memory, rapid naming and automaticity of basic skills. Difficulties in organisation, sequencing, and motor skills may also be present.
2.47 The ROI Task Force also recognises that learning difficulties associated with dyslexia
· occur across the lifespan, and may manifest themselves in different ways at different ages;
· may be associated with early spoken language difficulties;
·may be alleviated by appropriate intervention;
· increase or reduce in severity depending on environmental factors;
· occur in all socio-economic circumstances;
· co-exist with other learning difficulties such as Attention Deficit Disorder, and may or may not represent a primary difficulty.
2.48 They also recognise that, since the difficulties presented by students with dyslexia range along a continuum from mild to severe, they require a continuum of interventions and other services.
2.49 Recommendations
The Northern Ireland Task Group endorses the ROI definition:
Dyslexia is manifested in a continuum of specific learning difficulties related to the acquisition of basic skills in reading, spelling, writing and/or number, such difficulties being unexpected in relation to an individual’s other abilities. Dyslexia can be characterised at the neurological, cognitive and behavioural levels. It is typically described by inefficient information processing, including difficulties in phonological processing, working memory, rapid naming and automaticity of basic skills. Difficulties in organisation, sequencing, and motor skills may also be present.
It more comprehensively reflects the theoretical position held by most practitioners in Northern Ireland. In addition, it is our strongly held view that there is a range of difficulties presented by students with dyslexia, from mild to severe, and that there should be a range of interventions to address these needs.
·The Group recommends effective early intervention to minimise the risk of children suffering the negative experience of academic failure and associated consequences.
· It is essential that these interventions include whole school policies, within-class approaches and individual interventions at Stages 1 and 2 of the Code of Practice, as well as the type of external support available through the various ELB Services, as outlined in Chapter 3.
· In view of the recent developments in various fields of research, the Task Group recommends the convening of a regional conference to disseminate these findings.
FOOTNOTES:
21 Nicholson, R.I. (2001) in A. Fawcett (Ed) Dyslexia Theory and Good Practice
London: Whurr, (page 5)
22 Morton, J, and Frith, U. (1995): Causal Modelling: A structural approach to developmental psychopathology. In D. Cicchetti and D.J. Cohen (Eds) Manual of Developmental Psychopathology, New York: John Wiley and Sons, pages
357 – 90.
23 Frith, U. (1997): Brain, Mind and Behaviour in Dyslexia. In C. Hulme and M J
Snowling (Eds) Dyslexia: Biology, Cognition and Intervention, London: Whurr, pages 1 - 19
24 Snowling, M.J. 1987: Dyslexia: A Cognitive Developmental Perspective. Oxford. Blackwell
25 Snowling, M. J. (2001): Dyslexia: 2nd Edition. Oxford. Blackwell
26 Stanovich, K.E. (1988) Explaining the differences between the dyslexic and garden-variety poor reader: the phonological-core variable-difference model.
Journal of Learning Disabilities 21: pages 590 - 612
27 Frith, U. (1997): Brain, Mind and Behaviour in Dyslexia. In C. Hulme and M.J.
Snowling (Eds) Dyslexia: Biology, Cognition and Intervention, London: Whurr, pages 1 - 19
28 Elbro, C et al (1998) Predicting dyslexia from kindergarten. The importance of distinctness of phonological representations of lexical items. Reading Research Quarterly 33: pages 36 – 60.
29 Hulme, C et al (1995) Practitioner review: Verbal working memory development and its disorders. Journal of Child Psychology and Psychiatry, 36, pages 373 –98.
30 Stanovich K.E. et al (1997): Progress in the search for dyslexia subtypes. In C
Hulme and M. J. Snowling (Eds) Dyslexia: Biology, Cognition and Intervention,
London: Whurr, pages 108 - 130
31 Nicholson, R. I., Fawcett, A. J. (1990) Automaticity: a new framework for dyslexia research? Cognition 35(2): pages 159 - 182
32 Nicholson, R.I., Fawcett, A.J. (1995) Balance, phonological skill and dyslexia: towards the dyslexia early screening test. Dyslexia Review 7: pages 43 - 47
33 Fawcett, A.J. and Nicholson, R.I. (2000) in A. Fawcett (Ed) Dyslexia Theory and Good Practice London: Whurr, pages 89 – 105.
34 Stein J. F. et al Role of the cerebellum in visual guidance of movement
Physiological Reviews 72: pages 972 - 1017
35 Garzia R. P. et al (1993) Vision and Reading. J Opt Vis Dev 24: pages 4 - 15
36 Stein J. F. et al (2000) Controversy about the visual magnocellular deficit in developmental dyslexics. Trends in Cognitive Science 4: pages 209 - 211
37 Grigorenko, E. L. (2001) Developmental Dyslexia: an update on genes, brains and environments. Journal of Child Psychology and Psychiatry 42: pages 91-125
38 Miles, T. R. and Miles, E. (1984) Teaching needs of seven year old dyslexic pupils. Department for Education and Science, London
39 Chasty H. (1996) Review of Dyslexia: an avoidable national tragedy. Channel 4 documentary. Hopeline Videos, London
40 Grigorenko, E. L. (2001) Developmental Dyslexia: an update on genes, brains and environments. Journal of Child Psychology and Psychiatry 42: pages 91-125
41 Snowling M. J. (2000) in Dyslexia: 2nd edition. Oxford. Blackwell
42 Stanovich, K. E. (1986) Matthew effects in reading: Some consequences of individual differences in the acquisition of literacy. Reading Research Quarterly
16: pages 360 - 364
43 Stanovich, K. E. (1991) Discrepancy Definitions of reading disability: has intelligence led us astray?. Reading Research Quarterly 26: pages 7 - 29
44 Snowling, M. J. (2000) in Dyslexia: 2nd edition. Oxford. Blackwell
45 British Dyslexia Association @ www.bda.co.uk and associated publication
46 British Psychological Society (1999) dyslexia, Literacy and Phonological
Assessment: report of a Working Party of the Division of Educational and child
Psychology of the British Psychological Society, Leicester, BPS
47 Reason, R. (2001) Educational practice and dyslexia: The Psychologist 14, 6, pages 1 - 4
48 Nicholson, R.I. (2001) in A Fawcett (Ed) Dyslexia Theory and Good Practice
London: Whurr, (page 24)
49 Code of Practice on the Identification and Assessment of Special Educational
Needs (1998) DENI
50 Republic of Ireland Task Force on Dyslexia: 2001. Draft report