1.1 Introduction and Scope of the Review
In March 2007, the HM Inspectorate of Education commissioned The SCRE Centre at the University of Glasgow to undertake a review of the literature on the background to dyslexia, the range of teaching approaches used to teach children with dyslexia and the effectiveness of the various approaches. This literature review comprises a brief overview of the main educational, psychological and biological evidence, research/evaluation reviews, web-based materials and other references available to the researchers.
The purpose of this review is to inform HM Inspectorate of Education’s evaluation of the educational provision for children with dyslexia in Scotland, due to take place between April and December 2007. This review shows that there is an extensive array of published research literature on dyslexia because it is arguably the most common form of neurobehavioral reading disability (Shaywitz, 2003).
This brief report also provides an overview of the key findings from national and international studies, and concludes with some implications and recommendations for the Scottish education system. A conceptual map of the research field and the approach to the review are given in Appendices A and B.
Reports in the medical literature of ‘word blindness’ go back to the time when books first became relatively widely available to the population in Europe and reading became popular (Morgan, 1896 cited in O’Brien et al, 2005). The broad concepts of developmental dyslexia1 and specific learning difficulties (SLD) are connected to particular problems with reading. There are two key developments that have underpinned a huge leap in general knowledge and understanding about dyslexia. Recent policy encouraging inclusion of pupils with additional needs in mainstream schooling in the UK and elsewhere has been linked with legislation designed to support the educational needs of all children and people with disabilities, including dyslexics (Pirrie et al, 2006). The other key development relating to dyslexia concerns recent findings in the field of biological research. These relate to the underlying mechanisms of dyslexia and brain behaviour. There is also a significant body of research about the genetic determination of dyslexia and the importance of environmental influences (Grigorenko, 2001; Snowling & Hayiou-Thomas, 2006).
Dyslexia is viewed as the most commonly recognised form of specific learning difficulty (SLD). Other neurodevelopmental syndromes also considered as ‘specific learning difficulties’ are: dyspraxia, specific language impairment (SLI) and hyperactivity and attention deficit (Deponio, 2005). An individual child may often exhibit more than one of these complex syndromes. It is argued that the co-occurrence of these disabilities may be caused by overlapping developmental pathways and interacting genetic and environmental influences (Duane, 2002). Dyslexia is also often linked to other conditions, such as Attention Deficit Hyperactivity Disorder (ADHD) and/or other specific and general reading difficulties (Pope & Whiteley, 2003).
Estimates of the prevalence of dyslexia vary across countries from around 10 per cent to 17.5 per cent. In the UK the figure has been reported in the literature to be as high as 20 per cent (Chan et al, 2004; Feeg, 2003; Grigorenko, 2001; Shaywitz, 2003). For the purpose of providing a basis for intervention including assessment and teaching of individuals with severe persistent word reading problems, the British Psychological Association have defined dyslexia as follows:
Dyslexia is evident 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.
(British Psychological Society, 2005, p. 18)
This is the working definition of dyslexia that is adopted in the present review. Describing dyslexia as relating to the processing of information that affects the development of literacy has proved to be a helpful starting point for identification purposes. According to Reid and Fawcett (2005), other broad characteristics of developmental dyslexia, which may persist to a greater or lesser extent in an individual over their lifetime, include:
Saint Augustine remarked with astonishment upon the fact that Saint Ambrose, the bishop of Milan, could read silently, without pronouncing any words aloud (Augustine, Confessions 6.3). Speculating on this remark, historians (Rudich, 1995, personal communication) have suggested that, in those times, the majority of readers only knew how to read aloud: they did not practice reading silently to themselves. It is plausible that comparative genetic studies of populations whose linguistic systems differ will reveal some clues about the evolutionary path of normal and/or dyslexic reading in modern civilisation.
(Grigorenko, 2001, p. 114)
This anecdotal quote aptly shows that the association between reading silently (comprehension) and verbalisation of words out loud has a complex history. In fact, until fairly recently the term ‘dyslexia’ was often only applied to individuals with otherwise good communication skills and high Intelligence Quotient (IQ). Nowadays in the UK this ‘discrepancy model’ is no longer generally accepted by educational psychologists (BPS, 2005; see Vellutino et al, 2004).
Dyslexia is characterised as a problem with word recognition when speaking out loud. These problems are not specific to particular languages and the Intelligent Quotient (IQ) of individuals concerned. It can take the form of problems with phonological skills and recognising how to use the conventional sound structure of words, and also an atypically slow speed of remembering how to say words (Grigorenko, 2001). The type of dyslexic difficulties can be linked to the child’s first language. The simpler and more consistent the mapping of the alphabetic letters/symbols to sounds in a language, the less risk there is of children suffering phonological problems. In fact, languages with more complex orthographies, such as English, have a greater occurrence of this type of dyslexia (Snowling & Hayiou-Thomas, 2006). The research literature has found this to be true for various languages with differing degrees of orthographic complexity, including German, Italian, French, Dutch, Danish, English and Chinese (Grigorenko, 2001).
A detailed description of types of dyslexia, from mild to severe, and including surface and phonological, is given in Ho et al (2004). Goswami (2002) emphasises that the ability to detect rhyme forms in speech is part of the normal development of pre-reading skills in young children in different languages and this ability can be less evident in some dyslexics. Longitudinal studies in Sweden, which followed young children with dyslexia through to adulthood, have provided evidence that early phonological deficits can persist through to adulthood (Svensson & Jacobson, 2006). In Cantonese, a specific problem children experience is often due to the speed of remembering words (Chan et al, 2004).
Before embarking on a discussion about the causes of dyslexia, a broad outline of the basic processes involved in reading is required. According to Vellutino et al, (2004) the complex processes to be acquired and to occur automatically in order to read fluently and comprehend language include:
… parents provide not only the home environment but also the genes that will affect the child’s language and literacy skills.
(Snowling & Hayiou-Thomas, 2006, p. 120)
Vellutino et al, (2004) provide a useful cognitive framework for understanding the causes of dyslexia according to the research findings over the past forty years in terms of deficiencies in:
Historically there have been some cultural differences between psychologists in their main focus when studying the causes of dyslexia. Grigorenko (2001), for example, points out that in Asia and France the emphasis was more likely to be on inadequate motivation and educational opportunities for students than was the case in the UK and the USA.
Recent literature on the hereditary basis of dyslexia and other specific reading difficulties suggests a high multi-factorial genetic component, a strong environmental component and also significant genotype-environment interactions (based on twin studies) (Grigorenko, 2001). Researchers have isolated various genes on different chromosomes using a molecular genetic technique, known as Quantitative Trait Loci (QTL) identification. Putative chromosomes linked to families with dyslexic individuals include the chromosomes 2, 13, 14, 15 and X (Jenkins, 2005). It is interesting that the X chromosome is implicated because males are typically four times as likely as females to be dyslexic. A number of different chromosomes have been implicated in various molecular genetic studies (Grigorenko, 2001). Moreover, the base rates of reading disability in boys are generally much higher in twins, ie twin boys were only 60 per cent as likely as singletons to have adequate literacy standards by the age of 14 (Hay et al, 1984). Adoption studies of dyslexics may be a next step in understanding the interactions between genetics, development and the environment in young children. It has also been argued that environmental factors, such as parents’ attitude to education, could be related to the literacy skills of adopted children (Petrill et al, 2005).
Initial diagnosis and treatment of dyslexia usually involves a staged intervention process with many different tests and an observation checklist typically involving the following adults:
In the UK, teachers and parents usually play a crucial role in the initial diagnosis. The treatment will inevitably depend on whether the dyslexia is regarded as severe or mild. For more details about screening tests used in connection with looking at the whole child, the reader is referred to McIntyre and Deponio (2003). A useful selection of published tests for dyslexia identification is also given in BPS (2005). Cognitive profiling followed by screening using behaviour checklists and literacy measures has been applied in a large-scale research study in Hong Kong. The type of testing produced some false positives and it depends on an arbitrary cut off, the appropriateness of which is open to debate in the literature (Ho et al, 2004; Snowling, 2005).
In England, there is some limited evidence that teachers have been resistant to using the term ‘dyslexia’ (Regan & Woods, 2000). Paradice (2001) points out the importance of establishing a common understanding of the research evidence between parents and professionals through initial discussions prior to a child’s diagnosis. This dialogue can be difficult to sustain due to a somewhat emotive debate about ‘dyslexia’ in the popular media (Levelt, 2001; Elliott, 2005). Indeed, there is research indicating that not all teachers in England agree that it is important to consider a child’s family history, in terms of reading difficulties and current parental reading skills, before making a diagnosis of dyslexia (Lawrence & Carter, 1999).
From the review of the literature, we found that there are some collaborative projects on dyslexia involving voluntary, government and private organisations in Scotland (Reid & Fawcett, 2005). Reid et al (2005) also found from their study that ‘all authorities in Scotland seemed to be engaged in some way in the area of dyslexia/SpLD’ (p. 212), yet, it can be observed that there is a dearth of published studies on diagnosis, treatment and best practice undertaken in the Scottish setting.
… the pressure imposed by an industrialised society on a child with developmental dyslexia to master reading is of remarkable magnitude…Yet, if a person then ‘escapes’ the pressure of educational institutions by ending his or her education, or dropping out of school, or foregoing reading, the difficulties suppressed and alleviated by the pressure of the environment resurface. (Grigorenko, 2001, p. 92
This quote paints a bleak picture of life for people of any age with dyslexia. Socio-economic status is consistently negatively correlated with oral language and literacy skills (Phillips & Lonigan, 2005). Vernon-Feagans (1996) found that children of disadvantaged families (on the Head Start programme) are behind their peers in terms of vocabulary size.
Not recognising their specific needs may lead to a sense of failure in children that persists into adulthood (Reid & Given, 1998). Some evidence of links between adolescents’ sense of self-esteem and achievement in school and whether or not they engage in activities detrimental to their own health was mentioned in a report by the Committee on Dyslexia of the Health Council of the Netherlands (Gersons-Wolfensberger & Ruijssenaars, 1997) and also elsewhere (Feeg, 2003). However, there is now some light at the end of the tunnel for educators because the recent behavioural genetics research indicates the importance of both genetic and environmental influences in both typical and atypical development of language and literacy skills (Snowling & Hayiou-Thomas, 2006). Although the magnitude of the contribution of shared book reading on a child’s print knowledge is not yet clearly defined, the contribution of the home literacy environment on variables related to a child’s early literacy development is not in dispute.
Snowling et al (2003) have emphasised the importance of early identification in pre-readers of a very young age of the precursors of dyslexic-type symptoms in order to facilitate the development of compensatory reading strategies. Indeed, Snowling and Hayiou-Thomas (2006) suggest that with appropriate intervention, children with average oral comprehension skills and classic dyslexia symptoms, and also children with specific learning impairments in both oral and written comprehension, should be able to respond to appropriate teaching interventions, and become relatively normal readers. Their model has been developed in response to new knowledge and understanding about co-occurring syndromes and assumes that ‘some poor readers, whose phonological difficulties are either severe or complex (co-occurring with non-phonological deficits), require a different form of intervention’ (p. 122). They propose that all intervention programmes should include fundamental skills that are important for reading comprehension.
West (1997) has emphasised the special visual and spatial talents exhibited by some dyslexics, not only in the expressive arts but also in engineering. More generally, Reid (2006, p. 31) discusses the need for teachers to be given professional development training in recognising and accommodating children’s different learning and emotional styles in order to implement successfully the inclusion agenda in Scottish schools.
Interventions previously reported as potential cures for dyslexia were often based on studies of children with multiple learning difficulties. The fact that many development and behavioural abnormalities often co-exist with dyslexia complicates the interpretation of some of the early research studies. Recent studies have concentrated on identifying the co-occurring characteristics, such as ADHD, which is one of the most likely factors to be associated with dyslexia (Pope & Whiteley, 2003). Various substances produced by genes have also been implicated, such as glactose (Goldstein & Obrzut, 2001). Indeed, the stimulation of the cognitive system using a Tactile Training Box (TTB) resulted in improvements to the psychomotor functioning and the reading skills of some dyslexics (Grigorenko, 2001). However, the dietary regime of the participants was not controlled and so one cannot exclude the possibility that dietary changes may have somehow influenced the reported findings.
Although not effective for improving word recognition, visual stimulation and tactile exercises have been used to improve reading comprehension and accuracy of dyslexics (Goldstein & Obrzut, 2001). Byl et al (1989) found that exercises, including throwing and catching balls, computational tasks, tongue-twisters and puzzles, and jumping and balancing, improved the spatial awareness of young boys with ADHD. The claims of a cure for dyslexia based on a specific exercise programme involving balance and visual focusing need further investigation (Pope & Whiteley, 2003).
There have been some major policies orientated directly towards dyslexic learners of all ages and circumstances in society (Reid & Fawcett, 2005). The DfES also commissioned a review of different approaches to dyslexia (Fawcett, 2002). Further details of some major policies are either given in the rest of the review or can be explored through the weblinks provided. These include:
The final section of this introduction presents a wide range of issues in order to highlight the complexity of the additional needs of dyslexic learners, and paying particular attention to the situation in Scotland. The Additional Support for Learning (Scotland) Act was introduced in 2004. The principles and aspirations of the Act are to broaden the support for children with special needs, including dyslexia and to co-ordinate and focus professional support with a view to improving the educational potential of all young children. The statutory duty to deliver additional support rests with the local authorities in Scotland, but support needs are typically identified in schools. The majority of support packages are initiated and co-ordinated by schools and managed on a day-to-day basis by teachers.
Parents are the ones who usually have concerns and demand entitlement for their dyslexic children (Amatangelo et al, 2001; Hales, 2001). Regan and Woods (2000) report that teachers were not keen on administering tests themselves, although they were not averse to the screening of their pupils by outside experts. The teachers in this study, which took place in England, saw the main purpose of the screening tests to be the confirmation and validation of national tests. It was also mentioned that the teachers had not made full use of educational psychologists, in terms of encouraging them to develop participatory assessment protocols involving teachers, the children, and their parents (Lawrence & Carter, 1999; Regan & Woods, 2000).
On a related issue, scant research has been carried out on children with dyslexia for whom English is an Additional Language (EAL), and also on how dyslexics respond to learning foreign languages. However, the following quote encapsulates some of the inherent problems noted in the available literature:
One dilemma which we face [in Scotland] is whether or not we should present all young people with a common modern language curriculum irrespective of any additional support needs which they may have, or deprive students of what may prove to be a worthwhile and satisfactory learning experience.
(Crombie, 1999)
Resolving the dilemma of how to identify dyslexia in multi-lingual children is still a challenge for experts working with children who are using more than one language at home and at school (Reid & Fawcett, 2005, p. 13). The BPS (2005) suggests a need for a culture-fair assessment and intervention.
Any review of dyslexia is not complete without mentioning dyscalculia (ie specific difficulties associated with learning mathematics) because ‘for some dyslexic students, "easy" things in Mathematics are hard and "hard" things can be easy’ (Henderson & Chinn, 2005, p. 302). Some of the examples where difficulties may arise include learning to count, recognise and say numbers and using everyday language to describe three-dimensional shapes (Henderson & Chinn, 2005).
In conclusion, the interaction between research findings, policy and teaching practices is a recurring theme in the literature about dyslexia.