Identifying, Assessing, and Treating Dyslexia at School

Stephen E.  Brock, John Davis and Catherine ChristoDevelopmental Psychopathology at SchoolIdentifying, Assessing, and Treating Dyslexia at School10.1007/978-0-387-88600-8_1© Springer Science+Business Media, LLC 2009

1. Introduction

Catherine Christo¹  , Stephen E. Brock   and John Davis²

(1)

Department of Special Education, Rehabilitation & School Psychology, California State University, Sacramento, 6000 J Street, Sacramento, CA 95819-6079, USA

(2)

Califonia State University, East Bay, 25800 Carlos Bee Blvd., Hayward, CA 94542-3095, USA

Catherine Christo (Corresponding author)

Email: christo@crus.edu

Stephen E. Brock

Email: brock_s@sbcglobal.net

If the 1990s were considered the decade of the brain (Bush, 1990), the second half of 20th century and the first decade of the 21st should be considered the era of reading research. During this time, a plethora of studies have identified how children learn to read. Education professionals now have a much greater understanding of reading development from developmental, neuropsychological, and instructional viewpoints. The results of this research have informed instruction for regularly progressing readers and provided much greater understanding of why reading may not develop along the expected trajectory for some readers. This information has not only increased our understanding of the reading process, but has also been informative for the identification of characteristics that put children at risk for reading failure and for the development of instructional interventions that promote reading success for struggling readers. This chapter begins with a review of why school professionals should read this book, and then defines dyslexia, answers common questions about dyslexia, and examines this disorder from the context of special education eligibility.

1.1 Why School Professionals Should Read This Book

Clearly, school professionals should be especially attentive to ensuring that all students learn how to read. The following facts illustrate the consequences of reading disabilities or dyslexia. Specifically, the paragraphs that follow describe how reading is essential to academic success and adult outcomes, is associated with delinquency, and is the most common learning disability referral. Moreover, failure to identify and address dyslexia early on can have a cumulative effect. This reality is especially disturbing given the fact that much progress has been made in the early identification of dyslexia and in the development of interventions that successfully address reading disabilities. Finally, this introduction also suggests that school professionals should be interested in this book given that there have been recent changes in how to most effectively respond to the needs of children at risk for dyslexia.

1.1.1 School Success and Adult Outcomes

Becoming a competent reader is essential to school and occupational success. Without adequate reading skills, students are limited in both academic and employment prospects (National Endowment for the Arts, 2004). Reading is a foundational skill that is critical in acquiring content knowledge in academic areas such as science and social studies. Students with poor reading skills are at increased risk of dropping out of school (Frieden, 2004). Additionally, adults with dyslexia and other learning disabilities face greater difficulties in many aspects of adult life such as relationships and health (Mellard & Woods, 2007).

1.1.2 Association with Juvenile Delinquency

Further highlighting the need for educators to be better informed about reading disabilities is the relationship between dyslexia and youth who have had trouble with the law. Specifically, dyslexia has been documented to be more prevalent among adjudicated youth than in the general population. For example, Shelley-Tremblay, O’Brien, and Langhinrichsen-Rohling (2007) report that though prevalence rates vary all … indicate that the rate of reading disabilities among juvenile delinquents is significantly higher than rates of reading disabilities among the general school-aged population (p. 381). O’Brien, Langhinrichsen-Rohling, and Shelley-Tremblay (2007) found that 34% of incarcerated youth had reading problems; while Finn, Stott, and Zarichny (1988) reported that 43% of the adjudicated youth were two or more grade levels behind in reading. Incarcerated youth with reading problems are also found to have higher recidivism rates than those with adequate reading skills (Archwamety & Katslyannia, 2000).

1.1.3 The Most Common Learning Disability Referral

Reading problems are the predominate concern for children identified as having learning disabilities. They have been estimated to account for at least 80% of the referrals for learning disability evaluation (Lyon et al., 2001). Furthermore, the President’s Commission on Excellence in Special Education (U.S. Department of Education, 2002) reports that over half the students receiving special education services had reading problems.

1.1.4 Importance of Early Identification and Intervention

Much progress has been made in early identification of children who are at risk for reading difficulties (Badian, 2000; Blachman et al., 2004; Foorman, Breier, & Fletcher, 2003; Shaywitz, 2003; Shaywitz & Shaywitz, 2004; Uhry & Clark, 2004). This has led to the development of measures that are useful in identifying children who exhibit risk factors for reading difficulties (Al Otaiba & Fuchs, 2002, 2006; Davis, Lindo, & Compton, 2007; Foorman, 2003; Schatschneider & Torgesen, 2004; Vaughn & Fuchs, 2003).

Along with studies designed to identify risk factors, there has been a considerable amount of research regarding the benefits of early interventions and the difficulties students face when they are not provided with these services (Torgesen, 2002b). The majority of children (around 70%) who are poor readers in the primary grades continue to read poorly (McCardle, Scarborough, & Catts, 2001; Scarborough, 1998a, 1998b). In a landmark study, Juel and Leavell (1988) followed children’s reading development during the primary grades and found that children who were poor readers in first grade remained poor readers in fourth grade, too. Stanovich (1986) used the term Matthew effect to describe the downward trajectory that poor readers experience in relation to normally developing peers if they do not receive adequate intervention. He described a trajectory wherein the gap between good and poor readers increases over time. Scarborough and Parker (2003) found that the gap did not necessarily increase in terms of standard scores, but that poor readers remained the same distance behind good readers. Other authors have also noted the virtual impossibility for poor readers to catch up if their reading trajectory is not changed within the first few years of schooling (Catts, Hogan, & Fey, 2003; Torgesen et al., 2001).

Conversely, the benefits of early intervention have been well documented (Foorman, 2003). For example, Denton and Mathes (2003) note that early intervention can be powerful in bolstering later student achievement. Torgesen (2002a, 2002b, 2004) has also demonstrated the positive impact of early intervention. Good classroom-level interventions are estimated to reduce the number of at-risk readers from 25% of the population to 6%. Further, more intensive, supplemental interventions can reduce the number of struggling readers to 3–4% (Foorman). In addition, recent research has demonstrated that brain functioning, observed through imaging studies of struggling readers, can be changed to more closely resembling typically developing readers following intervention (Shaywitz & Shaywitz, 2004; Simos et al., 2007). Achievement data accumulated through the Reading First program demonstrate improvements in reading for nearly every grade and subgroup (e.g., Hispanic, African American, disabled, English language learners, and economically disadvantaged; U.S. Department of Education, 2007).

1.1.5 Changes in How School Professionals Respond to Dyslexia

As a result of findings reflecting the effectiveness of early intervention, there has been a recent call for more efficient models for providing these interventions (Mellard & Johnson, 2008). While the value of early intervention for reading problems has been clearly established, many existing systems are not designed to provide sufficient intervention services to children until they are beyond the early primary years and are exhibiting more substantial academic deficits.

The cited research findings have also led to reconsideration of how special education eligibility is determined and whether only students deemed eligible for special education should receive the services needed to increase their likelihood of academic success. This has resulted in an approach to intervention and eligibility considerations, which relies on student response to intervention (RTI) for determining who is in greatest need of intervention services. RTI approaches have as key elements early intervention with research-based instructional programs and frequent monitoring of student progress. Such approaches hold promise for significantly reducing the number of children who will have ongoing reading problems.

However, even when implementing the most effective interventions there are still students who will struggle with learning to read. Characteristics of children less likely to respond to interventions have been identified (Fawcett & Nicolson, 2000; Muter, 1994). They include deficits in phonological awareness (Adams, 1990; Shaywitz, 2003; Torgesen, Wagner, Rashotte, Burgess, & Hecht, 1997), rapid naming (Lovett, Steinback, & Fritjers, 2000; Spring & Davis, 1988; Spring & Farmer, 1975; Wolf, 1991; Wolf, Bowers, & Biddle, 2000), and vocabulary (Al Otaiba & Fuchs, 2006). Methods of screening that operationalize these characteristics will be discussed further in Chap. 4.

1.2 Defining Dyslexia

To better understand the subject of this book and to set the stage for the chapters that follow, the following section reviews both the history of dyslexia and the current conceptualization of this developmental psychopathology.

1.2.1 History

Beaton (2004) provides a brief discussion of the first appearance of the term dyslexia as well as the condition that is currently associated with this term. According to Beaton, Sir Henry Broadbent was the first to mention this disorder in 1872, when he described patients who had lost the ability to read following brain injury. However, perhaps the most well-known early researcher on dyslexia was James Hinshelwood who published a series of papers describing cases of what was called word and letter blindness. Hinshelwood went on to report on a family within which were found several cases of such word blindness.

The first English language scholarly reference to what we now refer to as dyslexia was published in the British Medical Journal by Dr. W. Pringle Morgan in 1896. One of the major difficulties with this original conceptualization was its assertion that dyslexia was caused primarily by a vision or a visual processing problem.

Morgan’s perspective was the most prevalent until Orton’s (1928) work, which introduced the concept of strephosymbolia, or simply put – problems with reversing letters and words. He proposed that there was a relationship between cerebral dominance and reading, which opened the door to viewing reading problems as due to more than just visual processing. Researchers such as Johnson and Myklebust (1967); Satz, Raredin, and Ross (1971); Witelson (1976); and Witelson and Rabinovitch (1972) continued this research and began to publish articles addressing right-hemisphere/spatial processing issues and left-hemisphere/linguistic deficits as possible causes of dyslexia. More recently, Liberman and Liberman’s groundbreaking work at the Haskins Lab helped to identify difficulties in phonological processing as a root cause of reading problems (Liberman, 1999; Liberman, Shankweiler, Liberman, Fowler, & Fisher, 1977; Shankweiler et al., 1995). The presence of phonological processing problems in poor readers has been replicated in numerous studies (Fletcher, Lyon, Fuchs, & Barnes, 2007) and is now a well-established element of current conceptualizations of dyslexia.

1.2.2 Current Conceptualizations

The most frequently cited definition of dyslexia was developed by a working group of the International Dyslexia Association (IDA; Lyon, Shaywitz, & Shaywitz, 2003). This definition reads as follows:

Dyslexia is a specific learning disability that is neurobiological in origin. It is characterized by difficulties with accurate and/or fluent word recognition and by poor spelling and decoding abilities. These difficulties typically result from a deficit in the phonological component of language that is often unexpected in relation to other cognitive abilities and the provision of effective classroom instruction. Secondary consequences may include problems in reading comprehension and reduced reading experience that can impede growth of vocabulary and background knowledge. (p. 2)

There are several key points in this definition. First is the statement that dyslexia is of neurobiological origin. This statement indicates that to be considered dyslexia the reading difficulty must not be attributable to external environmental causes, such as poor instruction, and that the difficulty lies somewhere within the individual.

Second, the definition is very clear that dyslexia is related to problems at the word level (single word decoding) and not primarily an issue of understanding what was read (Vellutino, Fletcher, Snowling, & Scanlon, 2004). According to Fletcher et al. (2007) word level reading disability (WLRD) is synonymous with ‘dyslexia’ (p. 85). The role of phonological processing is also highlighted in this definition. As noted earlier, difficulties in phonological processing have been identified by numerous researchers as a central feature of reading disabilities and problems with reading development. Further discussion of phonological processing and its role in reading development will be provided in Chap. 2.

Third, the difficulties in reading are unexpected. Within this definition, dyslexia would not apply to students whose cognitive abilities were significantly below their age peers, or those who had not received adequate instruction in reading.

Finally, the definition notes that problems in single word decoding can lead to reading comprehension problems, and to limited growth in vocabulary and background knowledge. If children are not able to decode words effortlessly and automatically, they will have fewer resources to use in constructing meaning from text. In addition, an inability to correctly identify words along with slow and labored reading will impede comprehension. The effects of limited reading on vocabulary development and other academic skills have been described by Cunningham and Stanovich (1999).

Similar to the IDA definition, the National Institutes of Health’s (National Institutes of Health & Development, 2007) definition of dyslexia emphasizes problems with word recognition and notes that individuals with this disability may have poor spelling, handwriting, and reading comprehension. The NIH definition is as follows:

Reading Disability is a reading and language-based learning disability, also commonly called dyslexia. For most children with learning disabilities receiving special education services, the primary area of difficulty is reading. People with reading disabilities often have problems recognizing words that they already know. They may also be poor spellers and may have problems with decoding skills. Other symptoms may include trouble with handwriting and problems understanding what they read. About 15 percent to 20 percent of people in the United States have a language-based disability, and of those, most have dyslexia. (¶ 8)

Another commonly referenced conceptualization of dyslexia is offered within the Diagnostic and Statistical Manual of Mental Disorders (4th Edition, Text Rev.; DSM-IV; American Psychiatric Association [APA], 2000), which places Reading Disorder within the class of Disorders Commonly Diagnosed in Infancy, Childhood or Adolescence (pp. 39–134) and is one of four Learning Disorders (with the others being Mathematics Disorder, Disorder of Written Expression, and Learning Disorder Not Otherwise Specified [NOS]). Within the description of this learning disorder, dyslexia is noted as a term that can also be used for Reading Disorder (pp. 51–52). The DSM-IV-TR description also notes that oral reading of persons with dyslexia is characterized by distortions, substitutions or omissions (p. 52). Problems in fluency are also highlighted in the DSM-IV-TR description: both oral and silent reading are characterized by slowness and errors in comprehension (p. 52). This description of the reading of individuals with Reading Disorder highlights similar difficulties in word-level identification, fluency, and comprehension included in the definition of dyslexia put forth by the IDA (Lyon et al., 2003). Further discussion of dyslexia criteria will be explored in Chap. 5, which addresses the topic of diagnosis. Table 1.1 provides a summary of the components of each of the definitions of dyslexia discussed here.

Table 1.1

Comparisons of dyslexia definition elements

1.3 Common Questions About Dyslexia

Two questions are frequently asked about dyslexia. The first is whether dyslexia is simply the low end of the reading skill continuum, and the second is whether there are different types of dyslexia.

1.3.1 Is dyslexia Just the Low End of the Reading Skill Continuum?

An important issue in defining dyslexia is whether dyslexia represents a unique disorder or the lower end of a continuum of reading skill. When dyslexia is defined on the basis of discrepancies between IQ and reading achievement, arguments against dyslexia being a valid clinical entity include (a) difficulty in differentiating between poor readers with low and high IQs (Shaywitz, Escobar, Shaywitz, Fletcher, & Makuch, 1992; Stanovich, 1993), (b) similar deficits in the key area of phonological processing (Fletcher & Shaywitz, 1994; Stanovich & Siegel, 1994), and (c) similar response to reading intervention programs (Felton, 1992). Thus, if dyslexia is conceptualized as problems in word recognition that have as their proximal cause difficulties in certain aspects of phonological processing, garden variety poor readers (Gough & Tunmer, 1986) cannot be distinguished from students with dyslexia on the basis of IQ and achievement discrepancies. Their reading problems, their underlying deficits, and their RTI are not sufficiently different to warrant categorization.

However, separate from the questions of IQ and reading achievement discrepancies, there is something unique about readers who struggle with basic word recognition. Specifically, there is substantial evidence for a unique phonological processing deficit defining dyslexic readers (which will be addressed further in Chap. 2). Performance on phonological processing tasks distinguishes good and poor readers from an early age, and is predictive of students who will struggle with the development of basic reading skills (the use of such tasks to predict who is at risk for reading difficulties will be addressed further in Chap. 4). In addition, interventions targeting phonological processing have been shown to be powerful remediation approaches. Such strong evidence of a clearly defined processing deficit linked to reading problems gives credence to the conceptualization of dyslexia as a unique disorder and not simply the lower end of the reading skill continuum.

In addition to the behavioral manifestations of a phonological processing deficit, neuroimaging studies have