The Education of Dyslexic Children from Childhood to Young Adulthood

ANRV331-PS59-14 ARI 17 August 2007 14:47 V I E E W R S I E N C N A D V A The Education of Dyslexic Children from Childhood to Young Adulthood Sally E. Shaywitz,1 Robin Morris,2 and Bennett A. Shaywitz3 1Department of Pediatrics, Yale University School of Medicine, New Haven, Connecticut 06510; email: [email protected] 2Department of Psychology, Georgia State University, Atlanta, Georgia 30302; email: [email protected] 3Departments of Pediatrics and Neurology, Yale University School of Medicine, New Haven, Connecticut 06510; email: [email protected] Annu. Rev. Psychol. 2008. 59:14.1–14.25 Key Words The Annual Review of Psychology is online at accommodations, classification, learning disabilities, neuroimaging, http://psych.annualreviews.org specific reading disability, reading remediation, reading This article’s doi: intervention 10.1146/annurev.psych.59.103006.093633 Copyright c 2008 by Annual Reviews. Abstract All rights reserved The past two decades have witnessed an explosion in our understand- 0066-4308/08/0203-0001$20.00 ing of dyslexia (or specific reading disability), the most common and most carefully studied of the learning disabilities. We first review the core concepts of dyslexia: its definition, prevalence, and developmental course. Next we examine the cognitive model of dyslexia, especially the phonological theory, and review empiric data suggest- ing genetic and neurobiological influences on the development of dyslexia. With the scientific underpinnings of dyslexia serving as a foundation, we turn our attention to evidence-based approaches to diagnosis and treatment, including interventions and accommodations. Teaching reading represents a major focus. We first review those reading interventions effective in early grades, and then review interventions for older students. To date the preponderance of intervention studies have focused on word-level reading; newer studies are beginning to examine reading interventions that have gone beyond word reading to affect reading fluency and reading compre- hension. The article concludes with a discussion of the critical role of accommodations for dyslexic students and the recent neurobiological evidence supporting the need for such accommodations. 14.1 ANRV331-PS59-14 ARI 17 August 2007 14:47 to decipher the code. Just how many are af- Contents fected, the basis of the difficulty, and most im- portantly, the most effective, evidence-based BACKGROUND AND approaches to educating dyslexic children and DEFINITION...................14.2 young adults were questions that had to wait Historical Roots .................. 14.2 until quite recently for resolution. We begin Definition: Core Constancy by reviewing the core concepts of dyslexia, Amid Refinements.............14.3 including its definition, epidemiology, cog- EPIDEMIOLOGY OF nitive model, and etiology, especially neuro- DYSLEXIA ...................... 14.5 biological influences. We next consider spe- Prevalence ....................... 14.5 cific evidence-based reading interventions for Developmental Course ........... 14.5 word-reading accuracy, fluency, and compre- Sex Differences in Dyslexia ....... 14.6 hension and then the exciting neurobiolog- COGNITIVE MODEL OF ical findings that together have given rise DYSLEXIA AND ITS to and must inform contemporary, evidence- IMPLICATIONS ................ 14.6 based approaches to the education of dyslexic Phonological Theory ............. 14.6 children. We conclude with a discussion Dyslexia in Different of the critical role of accommodations for Orthographies ................ 14.7 dyslexic students and the new neurobiolog- ETIOLOGY ........................ 14.8 ical evidence supporting the need for such Genetic Influences ............... 14.8 accommodations. Neurobiological Influences ....... 14.8 DIAGNOSIS AND TREATMENT ..................14.11 Historical Roots Diagnosis of Dyslexia .............14.11 Dyslexia has been described in virtually ev- Teaching Reading to Dyslexic ery ethnic group, language, and geographic Students ......................14.12 region. The original report, published as Early Intervention ................14.12 A on November Interventions for Older Students . .14.13 Case of Congenital Wordblindness 7, 1896, was prompted by the experience of Beyond Word Accuracy ...........14.13 a British physician, W. Pringle Morgan, with Treatment Resisters ..............14.15 his patient Percy F., age 14, for whom he pro- Response to Intervention .........14.15 vided the following description: Summary of Interventions ........14.16 Accommodations .................14.16 ...He has always been a bright and intel- ligent boy, quick at games, and in no way inferior to others his age. His great difficulty has been—and is now—his inability to BACKGROUND AND read. He has been at school or under tutors DEFINITION since he was 7 years old, and the greatest ef- forts have been made to teach him to read, For good readers, gaining meaning from print but, in spite of this laborious and persistent quickly and effortlessly, like breathing and training, he can only with difficulty spell out speaking, is a natural part of life. For these words of one syllable .... men and women, it is almost unimaginable Fluency: the ability how something that seems to come so nat- ...I might add that the boy is bright and to read words urally could be difficult for others. Without of average intelligence in conversation. His accurately, rapidly, doubt, since ancient times when man learned eyes are normal ...and his eyesight is good. and with good to use printed symbols to convey words and The schoolmaster who has taught him for intonation ideas, there have been those who struggled some years says that he would be the smartest 14.2 Shaywitz · Morris · Shaywitz ANRV331-PS59-14 ARI 17 August 2007 14:47 lad in the school if the instruction were en- speaking, reading, writing, and mathematics. tirely in oral ... (Morgan 1896, p. 1378). In contrast to this undifferentiated construct, the current definition explicitly categorizes Accommodations: What is so striking is the similarity of dyslexia as a “specific learning disability.” New Percy F. to the children we continue to see to adaptations within to the current definition over the previous the classroom, use of this day. Such clinical descriptions from ev- one is reference to dyslexia’s “neurobiologi- assistive technology, ery corner of the globe attest to the invari- cal origin,” reflecting the significant advances or provision of extra ance of dyslexia over both time and place. In in neuroscience, particularly the brain imag- time allowing learning-disabled his clinical vignette, Dr. Morgan captures the ing of reading and dyslexia that is discussed in essence of dyslexia: an unexpected difficulty in students to detail below. demonstrate their reading. New, too, is the incorporation of, and em- full knowledge phasis on, the importance of fluent reading: Decoding: Definition: Core Constancy Amid the ability to read text not only accurately, determining the pronunciation of a Refinements but also rapidly and with proper expression (Rep. Natl. Reading Panel 2000). Thus, the word by analyzing Current definition. The basic notion of the vowels and previous reference to “single word decoding” consonant dyslexia as an unexpected difficulty in read- is now supplanted by reference to “difficul- combinations within ing has remained constant across definitions ties with accurate and/or fluent word recogni- the word of dyslexia (Critchley 1970, Lyon 1995) as tion,” acknowledging converging data point- evidenced by the most current definition ing to the critical lack of the development of provided by a working group meeting in fluent reading as a hallmark of dyslexia that Washington, D.C., in 2002: persists into adolescence and then adulthood, even when accuracy improves. The lack of flu- Dyslexia is a specific learning disability that ent reading is observed clinically by reading is neurobiological in origin. It is character- that is effortful and slow; it is often consid- ized by difficulties with accurate and/or flu- ered the sine qua non of dyslexia, especially in ent word recognition and poor spelling and young adult and adult readers (Bruck 1998, decoding abilities. These difficulties typi- Lefly & Pennington 1991, Shaywitz 2003). cally result from a deficit in the phonological This renewed appreciation of the importance component of language that is often unex- of fluency should encourage its measurement; pected in relation to other cognitive abili- otherwise, many dyslexic children who can ties and the provision of effective classroom read accurately, but not fluently, will continue instruction ...(Lyon et al. 2003, p. 2). to go unnoticed (and untreated) within the Refinements from prior definitions. classroom (Katzir et al. 2006). Dyslexia (also referred to as specific reading As in the prior definition (Lyon 1995), disability) is a member of the family of emphasis is on the phonological weakness learning disabilities; in fact, reading disability giving rise to the reading (and speaking) is by far the most common learning disability, difficulties characterizing dyslexia. A range affecting over 80% of those identified as of studies has indicated phonological diffi- learning disabled (Lerner 1989). Although culties as the most robust (Fletcher et al. the recognition of dyslexia as a discrete entity 1994, Shaywitz et al. 1999, Stanovich & Siegel dates back over a century, the concept of a 1994) and specific finding (Morris et al. 1998) learning disability is relatively new. in dyslexic

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