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Dyslexia: what do paediatricians need to know?
OCCASIONAL REVIEW
Dyslexia: what do paediatricians need to know?
sufficient background knowledge of dyslexia so that he/she can make this contribution effectively. The obvious starting point in any paediatric consultation is to clarify the details of the presenting complaint but almost inevitably the child with a possible dyslexia is a challenge because there will be important aspects of the history that need to be established both from the teachers and the family. It is invaluable to establish at the outset of the consultation the route by which the child was referred for paediatric assessment. What was the referrer hoping to achieve? Was the referral instigated by the teacher or by the parents and the paediatrician should open discussion in a non-judgemental way which allows teachers and parents to air their concerns. The experience of one’s child failing academically is a difficult one. Parents of such children can all too often be met with opposition when what they need is reassurance that the problem is being taken seriously with all parties working together. Dyslexia is defined in the International Classification of Diseases in the following way: “Dyslexia or a specific reading disability is a difficulty learning to read, despite conventional instruction, adequate intelligence and sociocultural opportunity. It is dependent upon fundamental cognitive disabilities which are frequently of constitutional origin”. Dyslexia is a difficulty learning to read that is always present in the early years. The reading difficulty can however appear to ‘recover’ particularly for reading comprehension in more intellectually able children in secondary school. ‘Conventional instruction’ is often assumed to have taken place if the child has attended school regularly. However, this might be the area that the parents feel was inadequate and which might have led to them consulting a paediatrician. They may hold views that the teaching of reading in school was poor, or that it should have been ‘dyslexia-specific’ as their child’s difficulties came to light. They may feel that the instruction needed to be more intense or delivered on a one-to-one basis and are seeking to enlist the paediatrician as an advocate to achieve this. Alternatively, the teacher may have put in a huge amount of input, but the child’s difficulties remain and they are looking to the paediatrician for advice as to whether the child has any health or developmental predispositions that might have resulted in this persistent picture. There are also many complex theories around the causes of dyslexia and parents and teachers may consult a paediatrician because of their scientific training. They hope to get some interpretation of the efficacy of these treatments and are looking to be guided as to how to best support and manage the child’s dyslexia. The definition of dyslexia also refers to the concept of ‘adequate intelligence’ and this too may represent a significant challenge at a consultation. The so-called ‘discrepancy model’ whereby dyslexia is only defined if it is a specific difficulty and out of step from the child’s intelligence is contentious (Figure 1). Nevertheless, the term dyslexia is generally confined to a specific reading difficulty. Reading skills do vary along with intelligence in the normal population but in addition, dyslexic children fall within the normal distribution of reading skills when corrected for ability. Therefore, they do not form a ‘hump’ at the lower end of the normal distribution. However, there are a number of conditions which illustrate how an ability to decode
Anne O’Hare
Abstract Forty per cent of a child’s waking life is spent in school and one of the most intrusive impacts on the success or otherwise of this experience is that of reading difficulties. Developmental dyslexia has a high genetic contribution affecting 50% of children with dyslexic parents. The paediatrician may be consulted for a child with dyslexia to advocate, interpret predisposing factors in the child’s developmental and medical history and offer scientific interpretation of the vast range of theories and interventions proposed for dyslexia. The purpose of this article is to orientate the paediatrician to what they need to know, so that they can maximize their contribution in the care of children with developmental dyslexia within a multidisciplinary team. It will cover the epidemiology and definition, the underlying hypotheses and underpinnings as well as the clinical diagnosis and examination, the longer-term prospects for affected children and the role of interventions.
Keywords developmental dyslexia; phonological awareness; reading interventions; risk factors
Epidemiology and definition Dyslexia is a common condition affecting 10e15% of English speaking populations and is recognized more commonly in boys, who outnumber girls by 4:1. Dyslexia affects users of all written languages, but learning to read and write in English is particularly challenging because it has an opaque orthography and the relationship between letters and sounds is inconsistent and many errors are permitted. This is compounded by the later introduction of many subject and technical words which are multisyllabic and often contain Latin and Greek roots and affixes. The most prominent symptom in dyslexia is a relative inability to acquire word recognition in early school, resulting in problems marrying up the phoneme (speech sound) to the grapheme (its encoded or symbolic representation) on the page. This symptom should be an educational ‘flag’ with most children being recognized in early school, assessed and offered remediation and support within school with no resort to medical consultation outwith the usual universal health services. However, there are a number of exceptions to this pattern of identification and management, whereby paediatricians are approached by parents/carers, teachers and colleagues in other professions in order to contribute to the diagnosis and management of dyslexia. This article aims to give the paediatrician
Anne O’Hare MD FRCPCH Honorary Professor in the Section of Child Life & Health, University of Edinburgh, 20 Sylvan Place, Edinburgh EH91 UW, UK and Consultant Paediatrician at the Royal Hospital for Sick Children, Edinburgh, UK. Conflict of interest: none.
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Figure 1 Discrepancy between the spelling of a child with developmental dyslexia and their competence in visuo-motor figure drawing.
in reading is not synonymous with intelligence. Examples of this are children with a learning disability who ‘bark’ at print or children with autism spectrum disorders who are hyperlexical and in both these situations the child will not have the accompanying comprehension of what they are reading. Therefore, whilst adequate intelligence might appear in these examples to be irrelevant to the acquisition of reading, a low intelligence can impact on the so-called ‘top down’ skills in reading. The resulting poor world knowledge, vocabulary, attention and motivation may make successful reading acquisition more elusive for such children. Therefore it can be helpful to have some knowledge of the child’s intellectual/learning potential in the formulation of why he or she is experiencing difficulty learning to read. However, as dyslexia is regarded as a specific difficulty, it is an inappropriate term with which to label reading delay for children who have more general learning problems. However, the contrary situation can also arise whereby a child’s intellectual potential is underestimated and dyslexia discounted. Such a child might have a developmental phonological speech delay associated with the commonly accompanying delay in fine motor skills and the surface features of their poor speech and handwriting may lead the specific nature of their difficulty to be overlooked. The definition of dyslexia also encompasses sociocultural opportunities as an exclusionary factor and the paediatrician may be able to assist here by taking into consideration what is known about the context of the family and the child’s opportunities. Learning to read is a complex behavioural development and children who live in crowded homes with poor amenities or who have been ‘looked after’ have lower attainments in their academic skills from children with similar socioeconomic backgrounds. Also children who are neglected or abused can differentially experience more difficulties with speech and language development than other cognitive domains and this in turn can predispose them to reading difficulties. The mediators of poor reading for children with reduced sociocultural opportunities are highly complex and incorporate lack of parents’/carers’ reading to the child, anxiety which can interfere with concentration in school, motivation and application to read which is compounded by a disinterest in the child’s achievements from the parents or low expectations from the teacher. Possibly these are the reasons why dyslexia can appear to be a ‘middle class’ diagnosis as it
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might appear much more straightforward to exclude aspects such as poor sociocultural opportunities and inadequate instruction for children from these socioeconomic backgrounds. Finally, within the definition of dyslexia, there is the challenge of identifying ‘fundamental cognitive disabilities which are frequently of constitutional origin’. This may be the reason why the paediatrician is being consulted and is the most contentious area and so will be considered in some detail in the rest of this article, with some direction to extended reading. This challenge is much more for children with developmental dyslexia and it is important to remember that the brain and the environment work together to produce the neural networks for reading acquisition so although there may be constitutional cognitive disabilities, the poor reading difficulties can also be compounded by experiential factors. Acquired dyslexia is much less common than the developmental form. It can follow conditions such as dysphasia from acquired brain injury or visual difficulties such as onset ocular dyspraxia in ataxiaetelangiectasia and disconnection syndromes as seen in infarction of the splenium of the corpus callosum from ischaemia in the posterior cerebral artery territory following raised intracranial pressure. Conditions of acquired dyslexia are all individually rare but they should be suggested by the developmental trajectory, any evidence of regression and relevant and predisposing past medical histories. As there is frequently a presumption of mainstream education for these children, it is critical not to overlook the possibility of acquired dyslexia as a cause of poor academic attainment.
Causes of dyslexia There has been enormous progress made in understanding the pathogenesis of dyslexia with many contributions from carefully delineated neuropsychological and linguistic studies, complemented by information from the new techniques such as functional brain imaging (fMRI).
Phonological awareness Phonological awareness is appreciating the constituent speech sounds of a word and it has the largest body of evidence that it is an important deficit in dyslexia. Successful reading depends on skills in word identification combined with reading and language
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comprehension. The child needs to understand that the written words are ‘encoded’ or symbolized representations of the spoken words. Temple states that “dyslexia appears to involve a problem in learning to relate visual input to phonological representations” (Figure 2). Phonological representation allows the child to appreciate the constituent speech sounds of a word and then in turn, phonemic awareness is the ability to decompose words into these constituent sounds and map them onto orthographic or the written representation. Sight word learning depends on the child’s appreciation of alphabetic principles, that is to say that letters represent sounds. It is possible to learn to talk without this conscious appreciation of the individual phonemes but learning to read calls upon these skills. In turn, reading builds up the child’s capacity for both phonemic awareness and orthography and phonological representations, so that normal readers develop proficiency in language comprehension and fluent word identification and in that very process, build up their own underlying skills. In contrast, children with dyslexia compound their underlying weaknesses in these areas. Children with poor phonological awareness have problems in acquiring skills in speech sound combinations with rhyme and alliteration and syllable recognition and can be identified in nursery school. Their poor phonological representations are also contributed to by relative deficits in verbal short-term memory and verbal working memory. The former can be conceived as the skill that would be required to remember a forward digit span, whereas the latter refers to a manipulation in the so-called ‘mental workspace’ for a task such as a backward digit span. Verbal working memory is not synonymous with verbal intellect and it has a wide variability. However, dyslexic children with poor verbal working memory capacity struggle with maths as well as with literacy. Decreased phonological awareness is also accompanied by problems in rapid naming. Phonological awareness is now a generally accepted theory of dyslexia, although it is still unclear why some children develop their phonological skills later in the course of their dyslexia but that these skills remain less fluent, particularly in spelling and they still experience difficulty with orthographically irregular words. However, more controversy surrounds a related theory of rapid auditory processing which suggests that low level auditory
sensory processing difficulties underpin the poor phonological awareness. This hypothesis proposes that there are deficits in processing transient acoustic signals that impair the ability to discriminate phonemes or speech sounds and which in turn lead to the difficulty in establishing stable phonological representations. Adaptive computer game interventions that address the auditory processing deficits have been developed but with an equivocal evidence base. Other researchers have argued that these low level auditory deficits (and perhaps also low level visual deficits) are actually biological markers of dyslexia but are not causative.
Vision and reading The fact that dyslexia was originally known as ‘word blindness’ illustrates the importance assigned to the visual system as a potential underpinning of dyslexia. Although the strength of evidence in recent years has been clearly in support of phonological awareness problems in developmental dyslexia, there is still a good deal of work continuing into exploring vision and reading and some of this leads to postulated interventions which families and teaching staff may enquire about from the paediatrician. Particular attention has focused on the magnocellular system, sometimes known as the ‘transient system’ subserved by large neurones in the visual system that have a high conduction velocity and a high degree of sensitivity to movement and rapid change in the visual field. It has a role in saccadic eye movements and the visuo-attentional demands of encoding letter sequences. The difficulty in learning to read in dyslexia is hypothesized to exist because of disorders in these low level visual systems with involvement of abnormally developed thalamic magnocellular neurones, resulting in deficits in processing moving stimuli and thus impacting on the reading activity of saccadic eye movements. However, the magnocellular hypothesis has to be reconciled with the fact that dyslexics are impaired in reading single words and not just when they are tracking lines of text. Also children can learn to read normally whilst still having a transient system deficit and dyslexic children usually have no problems with visual acuity or visual masking under normal conditions. However, all readers do require greater luminosity as text gets smaller and closer together and visual processes do contribute some variance in predicting reading skills in poor readers. Many visual areas during reading show differences between controls and adults with dyslexia and there are 17 areas of the brain implicated in this way on functional brain imaging. The most replication is for the angular gyrus which is less active in dyslexic adults during rhyme detection but which shows greater activity during orthographic identification tasks. A number of observations have also been made about binocular control in children with dyslexia. Visual perceptual instability has been imputed for such children because they report the experience of small letters appearing to move around, change places and merge. Individuals with dyslexia, including adults and children, have also reported fading of text, blurring, movement of lines of text and report benefit from looking at text under grey and coloured overlays. It has been proposed that unintended eye movements are a particular problem for children if the eyes are converged at 30 cm for reading. The poor
Figure 2 “Dyslexia appears to involve a problem in learning to relate visual input to phonological representations” (Temple 2000).
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magnocellular function hypothesis proposes that individuals with dyslexia experience the line of the two eyes sight crossing and recrossing, thus objects seen by the two eyes move over each other and change places. Normally, the motion signals provided by each eye are fed back to the eye muscles to keep the eye steady under utro ocular control. However, a high instance of visual perceptual instability has been reported by some authors for children with reading problems. However, any causal relationship between reading and poor binocular coordination has not been established and the intervention efficacy of approaches employed to support visual difficulties and reading are equivocal. Intriguingly, there is also a biological model that challenges the contention that low level retinal magnocellular difficulties have a relationship to high level magnocellular performance. There is a condition of WilliamseBeuren syndrome associated with a hemideletion of chromosome 7q11.23 in which there is an impairment in retinal magnocellular pathways but no visual cortical disorder. Nevertheless, we know that nearly a quarter of children treated on an intense randomized controlled trial for phonological training will not improve their reading. Therefore it is likely that further work remains to be done to see how best to manage reading recovery for these children and this may involve continuing to examine the contribution of vision to reading.
dyslexic, and this is a risk which remains even if the child is adopted. The cognitive phenotype of this complex inherited learning disability is heterogeneous. Therefore a detailed family history of spoken and written language development across generations is helpful when trying to establish whether a reading difficulty arises from a developmental dyslexia. Speech and language delay and disorders are also very important in the pathogenesis of dyslexia. Children who enter school with receptive language impairments are at particular risk and, when followed up long-term, they underachieve academically compared to other children with similar nonverbal intellect. Some forms of speech and language disorder, such as verbal dyspraxia, are particularly intrusive to the acquisition of reading. Motor skills in children at risk for familial dyslexia are often delayed and many children in the school years will have clinical features of developmental coordination disorder. Comorbid conditions such as attention deficit hyperactivity disorder also have a raised prevalence in children with dyslexia.
Clinical examination The paediatrician may be seeing a child who is considered to have dyslexia because they are failing to improve in their reading with appropriate intervention but in fact they might have a more general learning difficulty or a speech and language impairment. An examination of their growth and body habitus to exclude conditions such as sex aneuploidies, occult neurocutaneous conditions and suboptimal head growth may all be appropriate. It can sometimes be quite difficult to confirm a history of regression because it may be a problem to obtain a true picture of the developmental trajectory of the reading difficulty and academic progress because a child has changed between teaching staff and it proves impossible to get a history from someone who has known the child in the classroom over time. However, any true picture of regression is clearly important to establish and rare neurodegenerative conditions such as Nieman Pick type C disease and adrenoleukodystrophy can present with progressive academic failure. Whilst vision and hearing deficits are not a cause of dyslexia, they are of course a cause of not being able to see text or to hear phonemes clearly. Sometimes a condition that results in progressive sensory impairment may cause confusion with dyslexia, particularly at the transition of children going up from primary to secondary school. A more contentious area might be what paediatricians should expect to do in the clinical examination for children who are otherwise normal, developmentally and physically. There are a number of straightforward aspects to consider, much of which can be established by talking to the teacher and parent, rather than having to examine these elements directly. This multidisciplinary addition to the paediatric contribution allows one to establish whether the child has an ability to understand the concepts and conventions about print. Do they know that words are made up of letters and that they are processed from left to right in written English and that they are demarcated by spaces. Does the child have letter level knowledge in terms of their phonological and orthographic awareness? Has the child had an assessment of their reading comprehension and word decoding level? The paediatrician may wish to directly measure elements of the child’s cognitive and linguistic skills such as assessing
Cerebellar hypothesis of dyslexia The cerebellar hypothesis proposes that there is a general learning disorder in dyslexia with a failure to automize reading and writing skills. Recent functional brain imaging in adults with dyslexia revealed that the right cerebellar declive and lentiform nucleus are the most significant areas in terms of differences between adult dyslexics and normally developed readers. These findings suggest that the brain phenotype in adults with dyslexia does relate to the different deficits of automization of language based processes such as grapheme/phoneme correspondence and rapid access to the lexicon for vocabulary. Many areas of the brain have been reported as differing between individuals with dyslexia and those who are unaffected, including the planum temporale, corpus callosum, thalamus and Wernicke’s area. However, the recent findings in the fMRI of the cerebellum involvement are intriguing for whilst they do not suggest that there are no other anatomical abnormalities associated with the linguistic deficits in dyslexia, they do fit with the increasing demonstration that the cerebellum is involved in learning sequences and in automization. These in turn support language processing and in conjunction with the abnormalities described in the lentiform nucleus, support the contention that dyslexia is a specific linguistic and reading automization impairment.
Clinical diagnosis The majority of children with dyslexia have the developmental form which has a very high genetic contribution. Linkage studies have implicated sites on chromosomes 6, 15, 1, 3, 16 and 19 with some of these sites linking solely for dyslexia and others for dyslexia in conjunction with specific language impairment. 50e60% of the variance in reading achievement and reading related abilities can be explained by genetic factors. There is a 50% risk for a child developing dyslexia if their parent is
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receptive vocabulary with the British Picture Vocabulary Scale to give a baseline against which their literacy difficulties can be interpreted. Phonological awareness and verbal memory can also be assessed. Verbal short-term memory can be measured with a forward digit span such as that found in the Aston Index, and the verbal working memory can be explored i.e. the child’s capacity to store and manipulate information in the mental auditory workspace, by the reverse digit span, again of something like the Aston Index (Figure 3). There are a range of assessments for phonological awareness; the JeromeeRosner Auditory Analysis and the Phonological Assessment Battery which look at aspects of phonological awareness such as alliteration, rhyming, semantic fluency and non-word reading. Dyslexia and developmental coordination disorder often coexist and handwriting difficulties can compound the problems of written language with a dyspraxic dysgraphia (an ‘uncertainty’ regarding the movements required to form letters, words and spacing). This can exacerbate the spelling orthography difficulties. Insights into coordination, motor sequencing and balance can be achieved through the neurodevelopmental examination of the sensory motor system using examination tools such as the Quick Neurological Screening Test. It is important not to overemphasize findings such as handeeye dominance and cross laterality difficulties as these have been incorrectly interpreted in the past as underpinning the dyslexia. There is no requirement to examine for low level sensory difficulties in terms of temporal processing or ‘scotopic sensitivity’ as their role in the causation of dyslexia remains equivocal.
skills may be mitigated by variations in cognitive and language skills. College students who are ‘recovered’ dyslexics may have reading comprehension that is the same as their age-matched student peers but, they have inaccurate and dysfluent word recognition and spelling skills. Some studies, however, have shown that adolescents with dyslexia have significant long-term impacts on their academic attainments with poor catch up in schools between the ages of 8e13 years. It has been argued that decoding instruction should not be thought of as an activity confined to early schooling. Many children, and particularly those with dyslexia, require ongoing instruction for word analysis and spelling, especially as they start to meet many multisyllabic words in their literature and text books as they enter early secondary school and many of these technical words will contain Latin and Greek roots and affixes.
Management Presuming that the non-dyslexic factors such as correcting refractive errors have been accounted for, the primary treatment for dyslexia is that of getting the reading instruction and environment right and this is under the auspices of the education department. The approach needs to incorporate alphabet knowledge activity and phonemic awareness. Identifying dyslexia can be helpful in its own right and contribute to reducing the child’s anxiety over their being to blame for the reading failure. Randomized controlled trials of phonological awareness training and of intensive small group interventions for reading have been shown to be effective. Sometimes it is appropriate to consider adding to these approaches in school by home-based programmes which build up the child’s capacity in phonological awareness. Visual treatments are more contentious. Eye movement exercises for unstable vergence may lead to improved perceptual abilities and saccade control but there is no adequate controlled trial to demonstrate how well this subsequently remediates the reading difficulty in dyslexia and also many children without dyslexia have similar unstable vergence. Similarly, there are still problems in interpreting whether there are any significant benefits to the use of coloured overlays or tinted glasses, which is work that is based on the reported observations by Mearns and Irlen of subjective benefit from coloured overlays reducing discomfort and difficulties with text. Randomized controlled trials of coloured overlays have not shown impressive improvements and most of the work has concentrated on reporting increase in the rate of reading and it is not clear how functional this change is in the long-term.
Prevention and prognosis Many general factors such as prematurity, birth asphyxia, developmental impairments of speech and language and coordination predispose children to failure when learning to read. The paediatrician can help identify when a child may be at risk of reading failure and discuss this with families to encourage a timely sharing of information with teachers and school to assist monitoring of the child’s entry into literacy. As developmental dyslexia is primarily associated with phonological skill deficiencies, vocabulary letter knowledge in late nursery and early primary school are recognized risk factors for reading difficulties. Some children with dyslexia do develop these phonological skills and they do learn to read but their spelling remains less fluent and they can struggle with orthographically irregular words e.g. confusing homophemes, that is to say words that sound the same but are spelt differently and have different meanings. The impact of these poor phonological
Fatty acid supplementation, reflex intervention, balance training [for dyslexia, dyspraxia and attention deficit (Ddat)] A number of interventions have been reported as beneficial in reading delay including some individuals with dyslexia, through the conduct of single randomized trials, Omega 3 fatty acid supplementation was reported to confer benefit in reading delay in children with developmental coordination disorder. Treatment replicating primary reflex movements advanced reading age for children with specific reading difficulties. Replicated randomized controlled trials have not yet been reported and the underlying potential mechanisms remain unclear.
Figure 3 Verbal memory and phonological representations/dyslexia.
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Muttey M, Stirling H, Spalding N. Quick neurological screening test. Revised Edn. Northumberland: Ann Arbour Publishers, 1978. O’Hare AE. A doctor’s perspective in specific learning difficulties (dyslexia). In: Reid Gavin, ed. Perspective on practice. Edinburgh: Moray House Publications, 1993: 65e80. Pernet CR, Poline JB, Demonet JF, et al. Brain classification reveals the right cerebellum as the best biomarker of dyslexia. BMC Neurosci 2009; 10: 67. doi:10.1186/1471-2202-10-67. Richardson AJ, Montgomery P. The OxfordeDurham study: a randomized controlled trial of dietary supplementation with fatty acids in children with developmental coordination disorder. Pediatrics 2005; 115: 1360e6. Thompson M. Aston index: A Classroom Test for Screening and Diagnosis of Language Difficulties. LDA; 1975. Vellutino F. Specific reading disability (dyslexia): what have we learned in the past four decades? J Child Psychol Psychiatry 2004; 45: 2e40.
Some approaches have been adopted into learning support strategies but the overall continuing approach to remediate reading difficulties incorporates primarily addressing the phonological and linguistic difficulties and enhancing educational intervention that draws on building up the skills that are causally associated with skilled reading success (www. teachernet.gov.uk).
Funding source No funding involved.
A
FURTHER READING Fawcett A. Report to the National assembly for Wales Enterprise and Learning Committee on issues surrounding the treatment for those with dyslexia, http://www.assemblywales.org/bus-home/buscommittees/bus-committees-third1/bus-committees-third-els-home/ bus-committees-third-els-agendas.htm?act¼dis&id¼63637&ds¼11/ 2007; 2007. Fredrickson N, Frith U, Reason R. Phonological assessment battery. Nelson: NFER, 1997. Grigorenko EL. Developmental dyslexia: an update on genes, brains and environments. J Child Psychol Psychiatry 2001; 42: 91e125. Henry MK. The decoding/spelling curriculum: integrated decoding and spelling instruction from preschool to early secondary school. Dyslexia 1997; 3: 178e89. Jerome- Rosner. Auditory analysis, Helping children overcome learning difficulties: a step by step guide for parents and teachers. New York: Walker and Company, 1975. Johnson S, Hennessy E, Smith R, et al. Academic attainment and special educational needs in extremely preterm children at 11 years of age: the EPICure study. Arch Dis Child Fetal Neonatal Ed 2009; 94: F283e9. Justice LM. Evidence-based practice, response to intervention, and the prevention of reading difficulties. Lang Speech Hear Serv Sch 2006; 37: 284e97. Khalid S, O’Hare AE. The association of abnormal cerebellar function in children with developmental co-ordination disorder and reading difficulties. Dyslexia 2002; 8: 234e48.
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Children with dyslexic parents have a 50% risk of experiencing reading difficulties. Developmental impairments of speech and language predispose to dyslexia. Children with dyslexia have poor phonological awareness and in their early years demonstrate difficulties in vocabulary development and alphabetic knowledge. The degree to which other features such as problems with visual systems, primitive reflexes and nutritional deficiencies remain controversial. The paediatrician can have a valuable role in helping to identify children at risk of dyslexia and contributing in a multidisciplinary team towards appropriate assessment and intervention. Referral for assessment and management from colleagues in speech and language therapy and occupational therapy may also contribute to the assessment and management of children with dyslexia and associated dysgraphia.
Ó 2010 Published by Elsevier Ltd.
Dyslexia: what do paediatricians need to know?
sufficient background knowledge of dyslexia so that he/she can make this contribution effectively. The obvious starting point in any paediatric consultation is to clarify the details of the presenting complaint but almost inevitably the child with a possible dyslexia is a challenge because there will be important aspects of the history that need to be established both from the teachers and the family. It is invaluable to establish at the outset of the consultation the route by which the child was referred for paediatric assessment. What was the referrer hoping to achieve? Was the referral instigated by the teacher or by the parents and the paediatrician should open discussion in a non-judgemental way which allows teachers and parents to air their concerns. The experience of one’s child failing academically is a difficult one. Parents of such children can all too often be met with opposition when what they need is reassurance that the problem is being taken seriously with all parties working together. Dyslexia is defined in the International Classification of Diseases in the following way: “Dyslexia or a specific reading disability is a difficulty learning to read, despite conventional instruction, adequate intelligence and sociocultural opportunity. It is dependent upon fundamental cognitive disabilities which are frequently of constitutional origin”. Dyslexia is a difficulty learning to read that is always present in the early years. The reading difficulty can however appear to ‘recover’ particularly for reading comprehension in more intellectually able children in secondary school. ‘Conventional instruction’ is often assumed to have taken place if the child has attended school regularly. However, this might be the area that the parents feel was inadequate and which might have led to them consulting a paediatrician. They may hold views that the teaching of reading in school was poor, or that it should have been ‘dyslexia-specific’ as their child’s difficulties came to light. They may feel that the instruction needed to be more intense or delivered on a one-to-one basis and are seeking to enlist the paediatrician as an advocate to achieve this. Alternatively, the teacher may have put in a huge amount of input, but the child’s difficulties remain and they are looking to the paediatrician for advice as to whether the child has any health or developmental predispositions that might have resulted in this persistent picture. There are also many complex theories around the causes of dyslexia and parents and teachers may consult a paediatrician because of their scientific training. They hope to get some interpretation of the efficacy of these treatments and are looking to be guided as to how to best support and manage the child’s dyslexia. The definition of dyslexia also refers to the concept of ‘adequate intelligence’ and this too may represent a significant challenge at a consultation. The so-called ‘discrepancy model’ whereby dyslexia is only defined if it is a specific difficulty and out of step from the child’s intelligence is contentious (Figure 1). Nevertheless, the term dyslexia is generally confined to a specific reading difficulty. Reading skills do vary along with intelligence in the normal population but in addition, dyslexic children fall within the normal distribution of reading skills when corrected for ability. Therefore, they do not form a ‘hump’ at the lower end of the normal distribution. However, there are a number of conditions which illustrate how an ability to decode
Anne O’Hare
Abstract Forty per cent of a child’s waking life is spent in school and one of the most intrusive impacts on the success or otherwise of this experience is that of reading difficulties. Developmental dyslexia has a high genetic contribution affecting 50% of children with dyslexic parents. The paediatrician may be consulted for a child with dyslexia to advocate, interpret predisposing factors in the child’s developmental and medical history and offer scientific interpretation of the vast range of theories and interventions proposed for dyslexia. The purpose of this article is to orientate the paediatrician to what they need to know, so that they can maximize their contribution in the care of children with developmental dyslexia within a multidisciplinary team. It will cover the epidemiology and definition, the underlying hypotheses and underpinnings as well as the clinical diagnosis and examination, the longer-term prospects for affected children and the role of interventions.
Keywords developmental dyslexia; phonological awareness; reading interventions; risk factors
Epidemiology and definition Dyslexia is a common condition affecting 10e15% of English speaking populations and is recognized more commonly in boys, who outnumber girls by 4:1. Dyslexia affects users of all written languages, but learning to read and write in English is particularly challenging because it has an opaque orthography and the relationship between letters and sounds is inconsistent and many errors are permitted. This is compounded by the later introduction of many subject and technical words which are multisyllabic and often contain Latin and Greek roots and affixes. The most prominent symptom in dyslexia is a relative inability to acquire word recognition in early school, resulting in problems marrying up the phoneme (speech sound) to the grapheme (its encoded or symbolic representation) on the page. This symptom should be an educational ‘flag’ with most children being recognized in early school, assessed and offered remediation and support within school with no resort to medical consultation outwith the usual universal health services. However, there are a number of exceptions to this pattern of identification and management, whereby paediatricians are approached by parents/carers, teachers and colleagues in other professions in order to contribute to the diagnosis and management of dyslexia. This article aims to give the paediatrician
Anne O’Hare MD FRCPCH Honorary Professor in the Section of Child Life & Health, University of Edinburgh, 20 Sylvan Place, Edinburgh EH91 UW, UK and Consultant Paediatrician at the Royal Hospital for Sick Children, Edinburgh, UK. Conflict of interest: none.
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Figure 1 Discrepancy between the spelling of a child with developmental dyslexia and their competence in visuo-motor figure drawing.
in reading is not synonymous with intelligence. Examples of this are children with a learning disability who ‘bark’ at print or children with autism spectrum disorders who are hyperlexical and in both these situations the child will not have the accompanying comprehension of what they are reading. Therefore, whilst adequate intelligence might appear in these examples to be irrelevant to the acquisition of reading, a low intelligence can impact on the so-called ‘top down’ skills in reading. The resulting poor world knowledge, vocabulary, attention and motivation may make successful reading acquisition more elusive for such children. Therefore it can be helpful to have some knowledge of the child’s intellectual/learning potential in the formulation of why he or she is experiencing difficulty learning to read. However, as dyslexia is regarded as a specific difficulty, it is an inappropriate term with which to label reading delay for children who have more general learning problems. However, the contrary situation can also arise whereby a child’s intellectual potential is underestimated and dyslexia discounted. Such a child might have a developmental phonological speech delay associated with the commonly accompanying delay in fine motor skills and the surface features of their poor speech and handwriting may lead the specific nature of their difficulty to be overlooked. The definition of dyslexia also encompasses sociocultural opportunities as an exclusionary factor and the paediatrician may be able to assist here by taking into consideration what is known about the context of the family and the child’s opportunities. Learning to read is a complex behavioural development and children who live in crowded homes with poor amenities or who have been ‘looked after’ have lower attainments in their academic skills from children with similar socioeconomic backgrounds. Also children who are neglected or abused can differentially experience more difficulties with speech and language development than other cognitive domains and this in turn can predispose them to reading difficulties. The mediators of poor reading for children with reduced sociocultural opportunities are highly complex and incorporate lack of parents’/carers’ reading to the child, anxiety which can interfere with concentration in school, motivation and application to read which is compounded by a disinterest in the child’s achievements from the parents or low expectations from the teacher. Possibly these are the reasons why dyslexia can appear to be a ‘middle class’ diagnosis as it
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might appear much more straightforward to exclude aspects such as poor sociocultural opportunities and inadequate instruction for children from these socioeconomic backgrounds. Finally, within the definition of dyslexia, there is the challenge of identifying ‘fundamental cognitive disabilities which are frequently of constitutional origin’. This may be the reason why the paediatrician is being consulted and is the most contentious area and so will be considered in some detail in the rest of this article, with some direction to extended reading. This challenge is much more for children with developmental dyslexia and it is important to remember that the brain and the environment work together to produce the neural networks for reading acquisition so although there may be constitutional cognitive disabilities, the poor reading difficulties can also be compounded by experiential factors. Acquired dyslexia is much less common than the developmental form. It can follow conditions such as dysphasia from acquired brain injury or visual difficulties such as onset ocular dyspraxia in ataxiaetelangiectasia and disconnection syndromes as seen in infarction of the splenium of the corpus callosum from ischaemia in the posterior cerebral artery territory following raised intracranial pressure. Conditions of acquired dyslexia are all individually rare but they should be suggested by the developmental trajectory, any evidence of regression and relevant and predisposing past medical histories. As there is frequently a presumption of mainstream education for these children, it is critical not to overlook the possibility of acquired dyslexia as a cause of poor academic attainment.
Causes of dyslexia There has been enormous progress made in understanding the pathogenesis of dyslexia with many contributions from carefully delineated neuropsychological and linguistic studies, complemented by information from the new techniques such as functional brain imaging (fMRI).
Phonological awareness Phonological awareness is appreciating the constituent speech sounds of a word and it has the largest body of evidence that it is an important deficit in dyslexia. Successful reading depends on skills in word identification combined with reading and language
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comprehension. The child needs to understand that the written words are ‘encoded’ or symbolized representations of the spoken words. Temple states that “dyslexia appears to involve a problem in learning to relate visual input to phonological representations” (Figure 2). Phonological representation allows the child to appreciate the constituent speech sounds of a word and then in turn, phonemic awareness is the ability to decompose words into these constituent sounds and map them onto orthographic or the written representation. Sight word learning depends on the child’s appreciation of alphabetic principles, that is to say that letters represent sounds. It is possible to learn to talk without this conscious appreciation of the individual phonemes but learning to read calls upon these skills. In turn, reading builds up the child’s capacity for both phonemic awareness and orthography and phonological representations, so that normal readers develop proficiency in language comprehension and fluent word identification and in that very process, build up their own underlying skills. In contrast, children with dyslexia compound their underlying weaknesses in these areas. Children with poor phonological awareness have problems in acquiring skills in speech sound combinations with rhyme and alliteration and syllable recognition and can be identified in nursery school. Their poor phonological representations are also contributed to by relative deficits in verbal short-term memory and verbal working memory. The former can be conceived as the skill that would be required to remember a forward digit span, whereas the latter refers to a manipulation in the so-called ‘mental workspace’ for a task such as a backward digit span. Verbal working memory is not synonymous with verbal intellect and it has a wide variability. However, dyslexic children with poor verbal working memory capacity struggle with maths as well as with literacy. Decreased phonological awareness is also accompanied by problems in rapid naming. Phonological awareness is now a generally accepted theory of dyslexia, although it is still unclear why some children develop their phonological skills later in the course of their dyslexia but that these skills remain less fluent, particularly in spelling and they still experience difficulty with orthographically irregular words. However, more controversy surrounds a related theory of rapid auditory processing which suggests that low level auditory
sensory processing difficulties underpin the poor phonological awareness. This hypothesis proposes that there are deficits in processing transient acoustic signals that impair the ability to discriminate phonemes or speech sounds and which in turn lead to the difficulty in establishing stable phonological representations. Adaptive computer game interventions that address the auditory processing deficits have been developed but with an equivocal evidence base. Other researchers have argued that these low level auditory deficits (and perhaps also low level visual deficits) are actually biological markers of dyslexia but are not causative.
Vision and reading The fact that dyslexia was originally known as ‘word blindness’ illustrates the importance assigned to the visual system as a potential underpinning of dyslexia. Although the strength of evidence in recent years has been clearly in support of phonological awareness problems in developmental dyslexia, there is still a good deal of work continuing into exploring vision and reading and some of this leads to postulated interventions which families and teaching staff may enquire about from the paediatrician. Particular attention has focused on the magnocellular system, sometimes known as the ‘transient system’ subserved by large neurones in the visual system that have a high conduction velocity and a high degree of sensitivity to movement and rapid change in the visual field. It has a role in saccadic eye movements and the visuo-attentional demands of encoding letter sequences. The difficulty in learning to read in dyslexia is hypothesized to exist because of disorders in these low level visual systems with involvement of abnormally developed thalamic magnocellular neurones, resulting in deficits in processing moving stimuli and thus impacting on the reading activity of saccadic eye movements. However, the magnocellular hypothesis has to be reconciled with the fact that dyslexics are impaired in reading single words and not just when they are tracking lines of text. Also children can learn to read normally whilst still having a transient system deficit and dyslexic children usually have no problems with visual acuity or visual masking under normal conditions. However, all readers do require greater luminosity as text gets smaller and closer together and visual processes do contribute some variance in predicting reading skills in poor readers. Many visual areas during reading show differences between controls and adults with dyslexia and there are 17 areas of the brain implicated in this way on functional brain imaging. The most replication is for the angular gyrus which is less active in dyslexic adults during rhyme detection but which shows greater activity during orthographic identification tasks. A number of observations have also been made about binocular control in children with dyslexia. Visual perceptual instability has been imputed for such children because they report the experience of small letters appearing to move around, change places and merge. Individuals with dyslexia, including adults and children, have also reported fading of text, blurring, movement of lines of text and report benefit from looking at text under grey and coloured overlays. It has been proposed that unintended eye movements are a particular problem for children if the eyes are converged at 30 cm for reading. The poor
Figure 2 “Dyslexia appears to involve a problem in learning to relate visual input to phonological representations” (Temple 2000).
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magnocellular function hypothesis proposes that individuals with dyslexia experience the line of the two eyes sight crossing and recrossing, thus objects seen by the two eyes move over each other and change places. Normally, the motion signals provided by each eye are fed back to the eye muscles to keep the eye steady under utro ocular control. However, a high instance of visual perceptual instability has been reported by some authors for children with reading problems. However, any causal relationship between reading and poor binocular coordination has not been established and the intervention efficacy of approaches employed to support visual difficulties and reading are equivocal. Intriguingly, there is also a biological model that challenges the contention that low level retinal magnocellular difficulties have a relationship to high level magnocellular performance. There is a condition of WilliamseBeuren syndrome associated with a hemideletion of chromosome 7q11.23 in which there is an impairment in retinal magnocellular pathways but no visual cortical disorder. Nevertheless, we know that nearly a quarter of children treated on an intense randomized controlled trial for phonological training will not improve their reading. Therefore it is likely that further work remains to be done to see how best to manage reading recovery for these children and this may involve continuing to examine the contribution of vision to reading.
dyslexic, and this is a risk which remains even if the child is adopted. The cognitive phenotype of this complex inherited learning disability is heterogeneous. Therefore a detailed family history of spoken and written language development across generations is helpful when trying to establish whether a reading difficulty arises from a developmental dyslexia. Speech and language delay and disorders are also very important in the pathogenesis of dyslexia. Children who enter school with receptive language impairments are at particular risk and, when followed up long-term, they underachieve academically compared to other children with similar nonverbal intellect. Some forms of speech and language disorder, such as verbal dyspraxia, are particularly intrusive to the acquisition of reading. Motor skills in children at risk for familial dyslexia are often delayed and many children in the school years will have clinical features of developmental coordination disorder. Comorbid conditions such as attention deficit hyperactivity disorder also have a raised prevalence in children with dyslexia.
Clinical examination The paediatrician may be seeing a child who is considered to have dyslexia because they are failing to improve in their reading with appropriate intervention but in fact they might have a more general learning difficulty or a speech and language impairment. An examination of their growth and body habitus to exclude conditions such as sex aneuploidies, occult neurocutaneous conditions and suboptimal head growth may all be appropriate. It can sometimes be quite difficult to confirm a history of regression because it may be a problem to obtain a true picture of the developmental trajectory of the reading difficulty and academic progress because a child has changed between teaching staff and it proves impossible to get a history from someone who has known the child in the classroom over time. However, any true picture of regression is clearly important to establish and rare neurodegenerative conditions such as Nieman Pick type C disease and adrenoleukodystrophy can present with progressive academic failure. Whilst vision and hearing deficits are not a cause of dyslexia, they are of course a cause of not being able to see text or to hear phonemes clearly. Sometimes a condition that results in progressive sensory impairment may cause confusion with dyslexia, particularly at the transition of children going up from primary to secondary school. A more contentious area might be what paediatricians should expect to do in the clinical examination for children who are otherwise normal, developmentally and physically. There are a number of straightforward aspects to consider, much of which can be established by talking to the teacher and parent, rather than having to examine these elements directly. This multidisciplinary addition to the paediatric contribution allows one to establish whether the child has an ability to understand the concepts and conventions about print. Do they know that words are made up of letters and that they are processed from left to right in written English and that they are demarcated by spaces. Does the child have letter level knowledge in terms of their phonological and orthographic awareness? Has the child had an assessment of their reading comprehension and word decoding level? The paediatrician may wish to directly measure elements of the child’s cognitive and linguistic skills such as assessing
Cerebellar hypothesis of dyslexia The cerebellar hypothesis proposes that there is a general learning disorder in dyslexia with a failure to automize reading and writing skills. Recent functional brain imaging in adults with dyslexia revealed that the right cerebellar declive and lentiform nucleus are the most significant areas in terms of differences between adult dyslexics and normally developed readers. These findings suggest that the brain phenotype in adults with dyslexia does relate to the different deficits of automization of language based processes such as grapheme/phoneme correspondence and rapid access to the lexicon for vocabulary. Many areas of the brain have been reported as differing between individuals with dyslexia and those who are unaffected, including the planum temporale, corpus callosum, thalamus and Wernicke’s area. However, the recent findings in the fMRI of the cerebellum involvement are intriguing for whilst they do not suggest that there are no other anatomical abnormalities associated with the linguistic deficits in dyslexia, they do fit with the increasing demonstration that the cerebellum is involved in learning sequences and in automization. These in turn support language processing and in conjunction with the abnormalities described in the lentiform nucleus, support the contention that dyslexia is a specific linguistic and reading automization impairment.
Clinical diagnosis The majority of children with dyslexia have the developmental form which has a very high genetic contribution. Linkage studies have implicated sites on chromosomes 6, 15, 1, 3, 16 and 19 with some of these sites linking solely for dyslexia and others for dyslexia in conjunction with specific language impairment. 50e60% of the variance in reading achievement and reading related abilities can be explained by genetic factors. There is a 50% risk for a child developing dyslexia if their parent is
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receptive vocabulary with the British Picture Vocabulary Scale to give a baseline against which their literacy difficulties can be interpreted. Phonological awareness and verbal memory can also be assessed. Verbal short-term memory can be measured with a forward digit span such as that found in the Aston Index, and the verbal working memory can be explored i.e. the child’s capacity to store and manipulate information in the mental auditory workspace, by the reverse digit span, again of something like the Aston Index (Figure 3). There are a range of assessments for phonological awareness; the JeromeeRosner Auditory Analysis and the Phonological Assessment Battery which look at aspects of phonological awareness such as alliteration, rhyming, semantic fluency and non-word reading. Dyslexia and developmental coordination disorder often coexist and handwriting difficulties can compound the problems of written language with a dyspraxic dysgraphia (an ‘uncertainty’ regarding the movements required to form letters, words and spacing). This can exacerbate the spelling orthography difficulties. Insights into coordination, motor sequencing and balance can be achieved through the neurodevelopmental examination of the sensory motor system using examination tools such as the Quick Neurological Screening Test. It is important not to overemphasize findings such as handeeye dominance and cross laterality difficulties as these have been incorrectly interpreted in the past as underpinning the dyslexia. There is no requirement to examine for low level sensory difficulties in terms of temporal processing or ‘scotopic sensitivity’ as their role in the causation of dyslexia remains equivocal.
skills may be mitigated by variations in cognitive and language skills. College students who are ‘recovered’ dyslexics may have reading comprehension that is the same as their age-matched student peers but, they have inaccurate and dysfluent word recognition and spelling skills. Some studies, however, have shown that adolescents with dyslexia have significant long-term impacts on their academic attainments with poor catch up in schools between the ages of 8e13 years. It has been argued that decoding instruction should not be thought of as an activity confined to early schooling. Many children, and particularly those with dyslexia, require ongoing instruction for word analysis and spelling, especially as they start to meet many multisyllabic words in their literature and text books as they enter early secondary school and many of these technical words will contain Latin and Greek roots and affixes.
Management Presuming that the non-dyslexic factors such as correcting refractive errors have been accounted for, the primary treatment for dyslexia is that of getting the reading instruction and environment right and this is under the auspices of the education department. The approach needs to incorporate alphabet knowledge activity and phonemic awareness. Identifying dyslexia can be helpful in its own right and contribute to reducing the child’s anxiety over their being to blame for the reading failure. Randomized controlled trials of phonological awareness training and of intensive small group interventions for reading have been shown to be effective. Sometimes it is appropriate to consider adding to these approaches in school by home-based programmes which build up the child’s capacity in phonological awareness. Visual treatments are more contentious. Eye movement exercises for unstable vergence may lead to improved perceptual abilities and saccade control but there is no adequate controlled trial to demonstrate how well this subsequently remediates the reading difficulty in dyslexia and also many children without dyslexia have similar unstable vergence. Similarly, there are still problems in interpreting whether there are any significant benefits to the use of coloured overlays or tinted glasses, which is work that is based on the reported observations by Mearns and Irlen of subjective benefit from coloured overlays reducing discomfort and difficulties with text. Randomized controlled trials of coloured overlays have not shown impressive improvements and most of the work has concentrated on reporting increase in the rate of reading and it is not clear how functional this change is in the long-term.
Prevention and prognosis Many general factors such as prematurity, birth asphyxia, developmental impairments of speech and language and coordination predispose children to failure when learning to read. The paediatrician can help identify when a child may be at risk of reading failure and discuss this with families to encourage a timely sharing of information with teachers and school to assist monitoring of the child’s entry into literacy. As developmental dyslexia is primarily associated with phonological skill deficiencies, vocabulary letter knowledge in late nursery and early primary school are recognized risk factors for reading difficulties. Some children with dyslexia do develop these phonological skills and they do learn to read but their spelling remains less fluent and they can struggle with orthographically irregular words e.g. confusing homophemes, that is to say words that sound the same but are spelt differently and have different meanings. The impact of these poor phonological
Fatty acid supplementation, reflex intervention, balance training [for dyslexia, dyspraxia and attention deficit (Ddat)] A number of interventions have been reported as beneficial in reading delay including some individuals with dyslexia, through the conduct of single randomized trials, Omega 3 fatty acid supplementation was reported to confer benefit in reading delay in children with developmental coordination disorder. Treatment replicating primary reflex movements advanced reading age for children with specific reading difficulties. Replicated randomized controlled trials have not yet been reported and the underlying potential mechanisms remain unclear.
Figure 3 Verbal memory and phonological representations/dyslexia.
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Muttey M, Stirling H, Spalding N. Quick neurological screening test. Revised Edn. Northumberland: Ann Arbour Publishers, 1978. O’Hare AE. A doctor’s perspective in specific learning difficulties (dyslexia). In: Reid Gavin, ed. Perspective on practice. Edinburgh: Moray House Publications, 1993: 65e80. Pernet CR, Poline JB, Demonet JF, et al. Brain classification reveals the right cerebellum as the best biomarker of dyslexia. BMC Neurosci 2009; 10: 67. doi:10.1186/1471-2202-10-67. Richardson AJ, Montgomery P. The OxfordeDurham study: a randomized controlled trial of dietary supplementation with fatty acids in children with developmental coordination disorder. Pediatrics 2005; 115: 1360e6. Thompson M. Aston index: A Classroom Test for Screening and Diagnosis of Language Difficulties. LDA; 1975. Vellutino F. Specific reading disability (dyslexia): what have we learned in the past four decades? J Child Psychol Psychiatry 2004; 45: 2e40.
Some approaches have been adopted into learning support strategies but the overall continuing approach to remediate reading difficulties incorporates primarily addressing the phonological and linguistic difficulties and enhancing educational intervention that draws on building up the skills that are causally associated with skilled reading success (www. teachernet.gov.uk).
Funding source No funding involved.
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FURTHER READING Fawcett A. Report to the National assembly for Wales Enterprise and Learning Committee on issues surrounding the treatment for those with dyslexia, http://www.assemblywales.org/bus-home/buscommittees/bus-committees-third1/bus-committees-third-els-home/ bus-committees-third-els-agendas.htm?act¼dis&id¼63637&ds¼11/ 2007; 2007. Fredrickson N, Frith U, Reason R. Phonological assessment battery. Nelson: NFER, 1997. Grigorenko EL. Developmental dyslexia: an update on genes, brains and environments. J Child Psychol Psychiatry 2001; 42: 91e125. Henry MK. The decoding/spelling curriculum: integrated decoding and spelling instruction from preschool to early secondary school. Dyslexia 1997; 3: 178e89. Jerome- Rosner. Auditory analysis, Helping children overcome learning difficulties: a step by step guide for parents and teachers. New York: Walker and Company, 1975. Johnson S, Hennessy E, Smith R, et al. Academic attainment and special educational needs in extremely preterm children at 11 years of age: the EPICure study. Arch Dis Child Fetal Neonatal Ed 2009; 94: F283e9. Justice LM. Evidence-based practice, response to intervention, and the prevention of reading difficulties. Lang Speech Hear Serv Sch 2006; 37: 284e97. Khalid S, O’Hare AE. The association of abnormal cerebellar function in children with developmental co-ordination disorder and reading difficulties. Dyslexia 2002; 8: 234e48.
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Children with dyslexic parents have a 50% risk of experiencing reading difficulties. Developmental impairments of speech and language predispose to dyslexia. Children with dyslexia have poor phonological awareness and in their early years demonstrate difficulties in vocabulary development and alphabetic knowledge. The degree to which other features such as problems with visual systems, primitive reflexes and nutritional deficiencies remain controversial. The paediatrician can have a valuable role in helping to identify children at risk of dyslexia and contributing in a multidisciplinary team towards appropriate assessment and intervention. Referral for assessment and management from colleagues in speech and language therapy and occupational therapy may also contribute to the assessment and management of children with dyslexia and associated dysgraphia.
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