LD with a special emphasis on reading disorders

LD with a special emphasis on reading disorders - SPECIAL...

Info icon This preview shows pages 1–13. Sign up to view the full content.

View Full Document Right Arrow Icon
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 2
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 4
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 6
Image of page 7

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 8
Image of page 9

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 10
Image of page 11

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 12
Image of page 13
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: SPECIAL ARTICLE This is the ninth in a series of [0-year updates in child and adolescent psychiatry prics are selected in consultation with theAACAP Committee on Recertzfication, hoth for the importance of new research and its clinical or developmental significance. The authors have heen asked to place an asterisk hefiire the five or six most seminal references. . McD. Learning Disorders With a Special Emphasis on Reading Disorders: A Review of the Past 10 Years JOSEPH H. BEITCHMAN, M.D., AND ARLENE R. YOUNG, PHD. ABSTRACT Objective: To review the past 10 years of clinical and research reports on learning disorders. Method: The most com- mon and best-researched type of learning disorder is reading disability, which is the focus of this review. A selective review of the literature from Psychological Abstracts and Index Medicus from 1985 to the present was conducted. This review focused on conceptual and methodological issues, current assessment practices, epidemiology, correlates of brain function, biological factors, predictors of reading achievement, core deficits, comorbidity, reading development and instructional approaches, treatment, and outcome. Results: Definitional issues, still unresolved, bedevil the field with the debate between those for and those against discrepancy definitions of reading disabilities. Nevertheless, considerable progress has been made. Phonological processing problems are now considered the main core deficit responsible for reading disabilities. Correlates of brain function and possible genetic factors are noted. Comorbidity with externalizing and internalizing disorders is described, and some theories for the overlap are identified. Studies on the comorbidity with internalizing disorders are lacking. Good assessment practice and promising approaches to remediation are identified. Unless a concurrent disorder is present, the use of medication for the treatment of reading disabilities should be consid- ered experimental. Favorable outcomes are dependent on initial severity and a supportive home and school environ- ment. Conclusions: Much progress has been made in our understanding of learning disabilities, especially in reading disabilities. Resolution of definitional and conceptual issues will greatly assist research into assessment, treatment, and long-term outcome of learning disabilities with and without concurrent psychiatric disorders. Further research into the nature, extent, and correlates of comorbid learning disabilities and their treatment is much needed. J. Am. Acad. Child Adolesc. Psychiatry, 1997, 36(8):1020—1032. Key Words: learning disorder, reading disability, literature review, phono- logical processing, comorbidity. According to the U.S. Department of Education (1991), nearly half of all children receiving special edu— cation services are considered learning—disabled. This represents approximately 4% to 5% of the school—age Accepted August 26, 1996. Dr. Beitehman is Head Chib' and Family Studies Centre, Clarke Institute of Psychiatry, Thronto, Canada. Dr. Young is with the Department of Psychology Child and Family Studies Centre, Clarke Institute of Psychiatry The authors thank Beth Wilson, B. Sc, and Isabel Lam, 3.11., for their assis— tance in the preparation of this manuscript. Reprint requests to Dr. Beitchrnan, Child and Family Studies Centre, Chrke Institute of Psychiatry 250 College Street, Titronto, Canada M5 T 1R8. 0890—8567/97/3608—1020/$0.300/0© 1997 by the American Academy of Child and Adolescent Psychiatry. 1020 population. The number of children identified as learn- ing—disabled has grown considerably since 1975, when the Education for All Handicapped Children Act (Public Law 94—142) required states to provide “free and appropriate public education” to all children with exceptionalities. WHAT IS A LEARNING DISABILITY? The definition used to classify children as learning- disabled is a critical and frequently contentious issue with important implications for identification, service provision, and research. Although the DSM—IV intro— duced the term “learning disorder,” few scientific pub— . AM. ACAD. CHILD ADOLESC. PSYCHIATRY, 36:8, AUGUST 1997 lications have used this terminology, preferring the terms “learning disabilities” and “reading disabilities” instead. Consequently, these latter terms are used in this review. Several definitions of learning disabilities exist. These definitions vary across several dimensions includ- ing the emphasis placed on underlying etiology (e.g., CNS involvement or underlying processing factors), the importance of specific academic skill deficits, and the definition of underachievement as an aptitude—achieve— ment discrepancy or a more broadly defined age or grade level expectation. The most cited and utilized def— inition (Hammill, 1990) is that of the National Joint Committee on Learning Disabilities (NJCLD, 1987), which states: Learning disabilities is a general term that refers to a heterogenous group of disorders manifested by significant difficulties in the acqui— sition and use of listening, speaking, reading, writing, reasoning, or mathematical abilities. These disorders are intrinsic to the individ— ual, presumed to be due to central nervous system dysfunction, and may occur across the life span. Problems in self-regulatory behaviors, social perception, and social interaction may exist with learning dis— abilities but do not by themselves constitute a learning disability (NJCLD, 1987, p. 1). The diagnostic criteria for learning disorder, used for applying for medical insurance coverage of diagnostic and treatment services, are likely to be based on criteria described in the most recent version of the DSM. The DSM—I V divides learning disorders into disorders of specific academic skills and a “not otherwise specified” category. Those involving specific academic skills include reading disorder, mathematics disorder, and dis— order of written expression. The “not otherwise spec— ified” category captures disorders in learning that do not meet criteria for any specific learning disorder. Within each of the specific academic skill disorders, the diag— nostic criteria requires that an individual’s actual achievement in a specific academic skill is substantially below his or her expected achievement as determined by standardized ability measures and that the learning problems interfere with academic achievement or related activities of daily living. While this definition appears relatively straightfor— ward, serious conceptual and pragmatic issues remain. For example, the specific method used to define a dis- crepancy and the size of a discrepancy needed to qualify as “serious” is not specified. State guidelines vary from requiring a difference of between one to two standard deviations in achievement and ability scores. The spe- cific methods used to compute discrepancies differ, 1. AM. ACAD. CHILD ADOLESC. PSYCHIATRY, 36:8, AUGUST 1997 LEARNING DISORDERS REVIEW however, and each approach will identify a.somewhat different group of children as learning—disabled (Cone and Wilson, 1981; Reynolds, 1984). Thus, despite the consensus that learning disabilities impair a child’s abil— ity to achieve at an age-appropriate achievement level, recurrent conceptual and methodological issues arise with nearly all definitions. Despite these difficulties, useful guidelines are available for practical decision- making and assessment of learning disabilities (e.g., Sattler, 1989). We recommend that a child’s actual level of functioning be considered as a first step in diagnosis. If a child is not functioning below expected level for age i or grade, he or she is unlikely to require special help to remediate a disability and should not be referred to as learning-disabled even if his or her IQ and ability scores are discrepant. LEARNING DISABILITY SUBTYPES Interest in discovering subtypes within the heteroge— neous learning-disabled population dates back several decades (e.g., Johnson and Myklebust, 1967) and remains a lively and promising focus of current research. While numerous classification and subtyping systems have been proposed, there is common recognition of both language-based disabilities, which are associated primarily with problems in reading and spelling, and a nonverbal type of disability associated most strongly with problems in arithmetic. This later subtype is asso— ciated with a pattern of deficits in neurocognitive and adaptive functions most often attributed to the right hemisphere, including problems in spatial cognition, visuoperceptual/simultaneous information processing, and social—emotional functioning. These disabilities are often referred to as right hemisphere or nonverbal learn— ing disabilities (NVLD), but very similar conditions have been described under the names of “nonverbal per— ceptual—organization—output disorders” (Rourke and Finlayson, 1978), left hemisyndrome (Denckla, 1978), and social-emotional learning disabilities (Voeller, 1991). Incidence rates based on clinical samples suggest that no more than 10% of learning disabilities are non- verbal (Denckla, 1991). An epidemiological study that used patterns of academic performance for subtyping found that 1.3% of a sample of 9- and 10-year-olds showed specific (arithmetic only) difficulties and 2.3% had difficulties in both arithmetic and reading (Lewis et al., 1994). Consistent with results of other studies, spe- cific reading difficulties were most frequent (3.9%). 1021 BEITCHMAN AND YOUNG NVLD have been shown to persist into adulthood and even to worsen over time. Furthermore, they place the NVLD individual at risk for socioemotional distur— bances, especially internalizing disorders (Casey et al., 1991; Denckla, 1991; Semrud—Clikeman and Hynd, 1990). The abnormal language characteristics (e.g., poor prosody and pragmatics yet good vocabulary) and pronounced social difficulties of these children have lead some investigators (e.g., Semrud—Clikeman and Hynd, 1990) to question whether there is a continuum of this disorder with pervasive developmental disorders, Asperger’s syndrome, and/or schizoid personality dis— order. While further research is needed on this issue, cli— nicians should consider the possibility of NVLD when encountering children with these psychiatric disorders. As noted above, the most common and, conse— quently, most well-researched type of learning disability is reading disability. Given its prominence and impor— tance, the remainder of this review focuses on reading disabilities unless otherwise stated. CONCEPTUAL AND METHODOLOGICAL ISSUES Despite the common practice of defining reading dis- abilities on the basis of IQ discrepancies, the validity of this approach remains controversial. In examining dis- crepancy definitions of reading disability, comparisons of two groups of children with poor reading achieve- ment are of interest. Children who show a discrepancy between their measured intelligence (IQ) and level of attainment in reading are typically referred to as dys— lexic, reading—disabled, or specific reading retarded (SRR). These poor readers had been thought to be qual- itatively different from garden variety poor readers (see below) and thought to be overrepresented, or to form a “hump” at the bottom of the normal curve (Rutter and Yule, 1975). Alternatively, children may have academic achieve— ment consistent with age and IQ level. That is, children with below-average IQ scores also show poor academic performance, as expected given their IQ level. These children are considered to have general reading back— wardness (GRB) or to have garden variety poor reading. In a recent review, Fletcher et al. (1993) cited work from several research centers (Share et al., 1987; Taylor et al., 1979), including their own, in which the performance of GRB and SR groups were compared. On the basis of the small effect sizes and nonsignificant differences in the comparisons between groups, they concluded that 1022 these groups resemble one another on a variety of cog— nitive variables (e.g., Siegel, 1992), neuropsychological profiles (Fletcher et al., 1993; Pennington et al., 1992), and sociodemographic and family characteristics (Shaywitz et al., 1992a). In addition, these GRB and SRR children are less easily distinguishable from one another as they develop, when their acquisition of gen- eral knowledge and vocabulary is further delayed by limited exposure to reading materials (Stanovich, 1986). These limitations also negatively affect IQ. Despite these similarities between the two poor reader groups described above, some differences are’evi— dent. Specifically, the SRR group has been shown to have better language skills than the GRB group (Silva et al., 1985). In contrast to Rutter and Yule (1975), Shaywitz et al. (1992a) reported a more favorable prog— nosis and outcome for the SR children in comparison with the GRB children. Similarly, reports by Jorm et al. (1986), McGee et al. (1986), and Richman et al. (1982) suggest that behavior problems are more strongly related to GRB than SRR. CURRENT ASSESSMENT PRACTICES The fundamental bases for assessing learning disabil— ities involve the use of a valid measure of intelligence and an assessment of academic content areas including reading, mathematics, and spelling through achieve— ment tests (Sattler, 1988). The most widely used test of intelligence is the WISC-III (Wechsler, 1991). The VVISC—III contains 13 subtests which combine to form the Verbal scale, the nonverbal or Performance scale, and the Full Scale IQ. Despite the controversy regard- ing the discrepancy definition of learning disabilities, IQ testing remains an integral part of the assessment process. In particular, IQ tests have been repeatedly shown to be correlated with and predictive of school achievement, and consequently they may guide expecta— tions regarding rate of achievement for a particular child. Furthermore, IQ tests such as the VVISC—III pro— vide a profile of strengths and weaknesses, important to understanding the nature of a child’s learning style and helpful in planning remedial or treatment programs. Assessing an array of cognitive processes including ver— bal, visuospatial, and constructional and planning proc— esses is important. Characteristic features of V/ISC-III profiles among learning-disabled children include varia— bility among subtests and lower mean scale scores on certain groupings of subtests such as the Symbol Search, 1. AM. ACAD. CHILD ADOLESC. PSYCHIATRY, 36:8, AUGUST 1997 Coding, Arithmetic, and Digit Span subtests (Prifitera and Dersh, 1993). Patterns of scores on IQ tests are not diagnostic of learning disabilities, however, nor do they differentiate learning—disabled children from other exceptional children (Kaufman, 1994). Furthermore, a significant discrepancy between Verbal and Performance 1Q alone does not constitute grounds for a diagnosis of learning disabilities. Besides standardized tests of cognitive ability and academic achievement, a thorough examination will also include measures of component skills within academic domains. An assessment for reading disabilities, for example, should include measures of a child’s ability to read words both in isolation and in text, ability to sound out unfamiliar words, knowledge of word sounds and corresponding letters and letter patterns, and reading comprehension skills. Child and situational character— istics that may contribute to or complicate academic progress should be considered. These include self- esteem, attentional abilities, peer relations, and demands on the child in school and within the family. Finally, consideration should be given to strengths and resources within the child, family, school, and community, which can be used to design elfective interventions. EPIDEMIOLOGY Estimates of the prevalence rate of reading disorders depends on the particular definition used. The field had been dominated by the Isle of Wight studies of Rutter et al. (1970) and Rutter and Yule (1975), in which a bimodal distribution of reading disorders was found. The “hump” at the lower end of the distribution was thought to reflect specific reading disabilities with an average prevalence of 5%. While this concept of reading disability as a discrete entity was the putative wisdom for many years, it did not go unchallenged. For exam— ple, Van der Wissel and Zegers (1985) argued that the bimodal distribution described by Rutter and Yule (1975) arose artificially because of the reading test used. The studies of Shaywitz et al. (1992b) have added further support to the point of view that reading dis— abilities are not a discrete, all—or-none phenomenon. Shaywitz et al. (1992b) argued that reading ability is normally distributed. According to this point of view, no biological equivalent of reading disabilities exists and the number of reading-disabled children identified depends on the cutoff point chosen. The cutoff point chosen maybe taken to be one standard deviation below J, AM. ACAD. CHILD ADOLESC. PSYCHIATRY, 36:8, AUGUST 1997 LEARNING DISORDERS REVIEW the mean, two standard deviations below the mean, or another point depending on the specific purpose. Recent studies showing no significant differences in the rates of reading disabilities between the sexes chal— lenge the commonly held view that reading disabilities prevalence rates are greater among boys than girls (Flynn and Rahbar, 1994; Shaywitz et al., 1990). Previously reported differences may to be due to biased referral practices by schoolteachers, in which boys with disruptive behaviour are preferentially referred for assessment. Girls with similar reading problems but without disruptive behaviour in the classroom are often" overlooked for referral. However, studies showing no sex differences in reading disabilities prevalence rates are restricted to samples of young children, in the fifth grade or lower (Shaywitz et al., 1996). To test whether sex differences exist at other ages, studies with older children and adolescents must be conducted. READING DISABILITIES AND THE BRAIN With the advent of imaging technologies, it has be— come possible to identify some structural and func— tional characteristics of the brains of learning—disabled children. Given that reading disabilities are thought to be due to deficiencies in language competence, it is not surprising that most positive findings in neuroanatom— ical studies of learning—impaired individuals have found evidence in support of a left hemisphere deficit. Some of these findings have emerged in postmortem cytoarchitectonic samples and in studies using mag- netic resonance imaging scans. In these studies, the planum temporale has been found lacking in the expected asymmetry (L > R) in children with language and learning disorders (Galaburda et al., 1985; Hynd and Semrud—Clikeman, 1989), though difficulties in reliably identifying the boundaries of the planum con- tinue to impede attempts to replicate earlier findings (Jernigan et al., 1991). On positron emission tomographic studies involving language tasks, differences in the left hemisphere of learning—disabled subjects compared with non—learning— disabled subjects have been shown (Flowers, 1993). On the basis of cerebral blood flow studies, Flowers (1993) concluded that there is a left temporal component associated with both phonological and orthographic skills requiring fine auditory dis— crimination and an inferior left parietal component associated with word meaning. Finally, Galaburda et al. 1023 BEITCHMAN AND YOUNG (1985) and Kaufman and Galaburda (1989) found that the brains of reading—disabled individuals had significantly more focal dysplasias, particularly in the language regions that border the sylvian fissure, than those of normal controls. The search for neuroanatomical and neurofunctional differences between reading—disabled and nondisabled children has not been limited to studies of brain regions but also includes studies of differe...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern