Issues in the definition and diagnosis of learning disabilities: a perspective on Guckenberger v. Boston University

This article reviews issues related to the definition of learning disabilities in the context of the Guckenberger v. Boston University case. Four major questions are addressed: (a) Who is learning disabled? (b) How should learning disabilities be assessed? (c) Who is qualified to make a decision about whether or not an individual has a learning disability? and (d) What accommodations should be provided by a postsecondary institution and how should they be selected? Although these are complicated and difficult questions, it is possible to develop a simple, reasonable classification system for learning disabilities, and to conduct assessments based on a coherent and relevant set of achievement tests in which individuals who score below a cutoff are considered learning disabled. Scores on IQ tests are irrelevant and not useful and may even be discriminatory. The issues of decision making regarding learning disabilities and appropriate accommodations remain significant dilemmas for the field; resolution of these issues seems virtually impossible without agreement on appropriate procedures for the definition, identification, and assessment of learning disabilities.     

What is the Role of Intelligence in the Identification of Specific Learning Disabilities? Issues and Clarifications

A fundamental assumption in the identification of specific learning disabilities (SLD) has been that the presence of a severe discrepancy between ability and academic achievement is a valid marker for the presence of a SLD. This assumption is based on the notion that discrepant low achievers constitute a unique group of children who are different in a number of ways from nondiscrepant low achievers. Several meta‐analytic reviews contrasting discrepant and nondiscrepant low achievers fail to reveal significant differences between these two groups on measures of phonetic analysis, pseudoword decoding, word identification, spelling, oral reading fluency and other measures of literacy development and related phonological processing skills. This paper discusses the role of intelligence in identifying children with SLD and presents data based on correlational analyses and hierarchical regression analyses showing that intelligence is not a strong predictor of reading achievement and does not predict responsiveness to remedial instruction. These data also indicate that direct measures of responsiveness to intervention (RTI) strongly predict later reading achievement in tutored children from 1st grade through 4th grade. The combined results suggest that RTI approaches to the identification of SLD may have greater utility than psychometric approaches based on IQ scores or individual profile analysis.     

Tourette syndrome and learning disabilities.

We reviewed the records of 42 consecutive cases of children with Tourette Syndrome (TS) who had IQs above 70, and contrasted the reading, reading comprehension, math, and spelling quotients with IQ scores to determine how many would meet criteria for a learning disability. The mean IQ of the 35 males and 7 females was 94.4 and was higher than the mean math score (82.8), spelling score (90.4), reading score (87.4), and reading comprehension score (85.3). Using a 1.5 standard deviation discrepancy, 51% met criteria for learning disability in at least one academic area; 21% had a 2-standard-deviation discrepancy. Children with TS frequently have learning disabilities, and assessment of academic achievement should be a routine aspect in the evaluation of such children.     

Contrasting Adult Literacy Learners With and Without Specific Learning Disabilities

Contrasting adult literacy learners with and without specific learning disabilities This study of 311 adult education (AE) learners found 29% self-reported having a specific learning disability (SLD). Significant differences in demographic, academic, and life experience variables between the adult learners with and without SLD included: prior participation in special education, having both an SLD diagnosis and a high school diploma, low reading scores, middle age, and negative perceptions about limitations due to reading abilities. A post-hoc regression analysis found SLD status significantly contributes to variance in reading level when controlling for age and IQ. From these findings we conclude that SLD status should be considered an educationally relevant variable in adult education that warrants a diagnostic or clinical teaching approach.     

Cerebellar tests differentiate between groups of poor readers with and without IQ discrepancy

A comprehensive test battery, including phonological, speed, motor and cerebellar tasks, was administered to the entire cohort of two schools for children with learning disabilities. Testing was undertaken blind without accessing the psychometric data on the children. Children were then allocated to a discrepancy group on the basis of their IQ, with the majority (n = 29) classified as nondiscrepant (IQ < 90) and a smaller set (n = 7), with IQ of at least 90, classified as discrepant (with dyslexia). Both groups showed significant deficits relative to age-matched controls on almost all the tests. On phonological, speed, and motor tasks, the nondiscrepant group were at least as severely impaired as the discrepant group. By contrast, on the cerebellar tests of postural stability and muscle tone, the nondiscrepant group performed significantly better than the children with dyslexia and close to the level of the controls. The findings indicate that cerebellar tests may prove a valuable method of differentiating between poor readers with and without IQ discrepancy. The findings are interpreted in terms of the cerebellar deficit hypothesis for dyslexia.     

The construct and predictive validity of a dynamic assessment of young children learning to read: implications for RTI frameworks

The purpose of this study was to examine the construct and predictive validity of a dynamic assessment (DA) of decoding learning. Students (N = 318) were assessed in the fall of first grade on an array of instruments that were given in hopes of forecasting responsiveness to reading instruction. These instruments included DA as well as one-point-in-time (static) measures of early alphabetic knowledge, rapid automatized naming (RAN), phonemic awareness, oral vocabulary, listening comprehension, attentive behavior, and hyperactive or impulsive behavior. An IQ test was administered in spring of second grade. Measures of reading outcomes administered in spring of first grade were accuracy and fluency of word identification skills and reading comprehension. Factor analysis using principal axis factor extraction indicated that DA loaded on a first factor that also included language abilities and IQ, which the authors refer to as the "language, IQ, and DA" factor. It was relatively distinct from two additional factors: (a) "speeded alphabetic knowledge and RAN" and (b) "task-oriented behavior." A three-level (children nested within classroom; classrooms nested within school) random intercept model with fixed effects predictors suggested that DA differed from word attack in predicting future reading skill and that DA was a significant predictor of responsiveness to instruction, contributing unique variance to end-of-first-grade word identification and reading comprehension beyond that explained by other well-established predictors of reading development.     

The validity of discrepancy-based definitions of reading disabilities.

This study addressed the validity of distinguishing children with reading disabilities according to the presence or absence of discrepancies between intelligence test scores and academic achievement. Three definitions of reading disability were used to provide criteria for five groups of children who (a) met a discrepancy-based definition uncorrected for the correlation of IQ and achievement; (b) met a discrepancy-based definition correcting for the correlation of IQ and achievement; (c) met a low achievement definition with no IQ discrepancy; (d) met criteria a and b; and (e) met none of the criteria and had no reading disability. Comparison of these five groups on a set of 10 neuropsychological tests corrected for correlations with IQ showed that group differences were small and accounted for little of the variability among groups. These results question the validity of segregating children with reading deficiencies according to discrepancies with IQ scores.     

Comparisons of cutoff and regression-based definitions of reading disabilities

This study addressed the issue of specificity in reading disability by comparing two approaches to defining and selecting children with reading disabilities. One approach defined reading disability according to cutoff scores representing appropriate levels of intelligence and reading deficiency, whereas the other approach adjusted these scores for their intercorrelation through regression procedures. Results revealed clear differences in which children were identified as reading disabled according to the two definitions. However, differences in neuropsychological performance between children whose reading scores were discrepant or not discrepant with IQ were small and nonspecific for both definitions. The results of this study show that children identified as reading disabled vary according to the definition employed; at this point, there is little evidence suggesting any specificity of reading disability according to definition.     

Growth in Precursor and Reading‐Related Skills: Do Low‐Achieving and IQ‐Discrepant Readers Develop Differently?

Poor readers who met low achievement and IQ‐discrepancy definitions of reading disability were compared with nonimpaired readers on their development of eight precursor and reading‐related skills to evaluate developmental differences prior to students’ identification as reading disabled. Results indicated no evidence for differences between the two groups of poor readers in the development of the eight skills, with three exceptions. Students in the IQ‐discrepant group demonstrated greater growth in letter sound knowledge, greater mean performance in visual‐motor integration at the beginning of first grade, and greater deceleration in rapid naming of letters. When compared to the nonimpaired group, low‐achieving readers demonstrated poorer performance and development in all skills, while the IQ‐discrepant readers demonstrated poorer performance and development in phonemic awareness, rapid naming of letters and objects, spelling, and word reading. The largely null results for comparisons between the two groups of poor readers challenges the validity of the two‐group classification of reading disabilities based on IQ‐discrepancy.     

A Critical Analysis of Siegel's Case for Revision of the Learning Disability Construct

In this paper I analyse Siegel's revisionist conceptualization of the learning disability concept. Siegel has attempted to demonstrate that the construct of learning disabilities is flawed because of its long‐term linkage with the variable of intelligence. The discrepancy formulation is the particular focus of her criticism. She has denigrated the use of IQ tests in LD diagnosis and argued that intelligence and reading measure many of the same abilities and therefore any difference between these two functions is confounded; that IQ is not a valid measure of reading potential in children with LD and normal populations; and that logical analysis and empirical research demonstrate that the concept of intelligence is redundant in any conception of learning disabilities. I present arguments against each of these propositions and several other matters raised in her paper. I propose two basic approaches to learning disabilities and give expression to these in two theoretical models, a simple categorical model (designated as Model C) and the underachievement model (Model D). I show that Siegel's interpretation is based on a weak version of Model C, but that this model fails to elucidate the essential meaning of the learning disability construct. I show that Model D is the more appropriate alternative. I contend that the application of standard regression procedures inherent in Model D would lead to a more appropriate definition of LD and that more stringent standards for the underachievement criterion would offset many of the problems that Siegel has highlighted in her paper.     

The irrelevance of IQ to the definition of learning disabilities: some empirical evidence

The relevance of IQ to the definition of learning disabilities is a much-debated issue. In this article, the effect of not using IQ in the identification of children with reading disabilities is demonstrated. Two classification procedures, differing in their use of IQ, are compared. The first conclusion is that abandoning IQ in classification has a very limited impact on the number of children identified as reading disordered. Our data demonstrate that, if IQ is used, more high IQ children are classified. Another finding pertains to the effect of a restriction of IQ range. The number of children classified as reading disordered is a function of the IQ range.     

Matthew effects in children with learning disabilities: Development of reading,IQ, and psychosocial problems from grade 2 to grade 8

Reading achievement, IQ, and behavior problems were assessed in second and eighth grade for a longitudinal sample of 57 children. Changes in these scores over time were compared for children with no learning disabilities versus children with math or reading disabilities (research-identified and/or school-identified). A widening of the group difference in IQ was seen between the math disabled and nondisabled groups, but otherwise the gaps between groups remained unchanged or narrowed over the six-year interval, indicating that hypothesized negative consequences of initial academic difficulties (“Matthew effects”) did not occur for most of the children with learning disabilities. Elevated rates of behavior problems were seen only for the group with math disabilities, suggesting that the type of learning disability needs to be taken into account in research on the association between academic and psychosocial problems.     

Etiological Factors in Reading Disability of the Academically Talented in Comparison to Pupils of Average and Slow-Learning Ability

Abstract

Etiological factors in reading disability for a high intelligence group were compared to those in average and low intelligence groups. All subjects were elementary and secondary pupils ranging from 7-1 to 15-10 in age. The twenty-six high intelligence subjects ranged from 113 to 128 in WISC IQ. The 146 subjects of average intelligence ranged from 88 to 112 in IQ. The thirty-four low intelligence subjects ranged from 70 to 87 in IQ. The subjects were administered several diagnostic tests to determine the etiology of their reading disabilities. When the etiological factors were divided into organic and functional categories, it was noted that the high intelligence group's disabilities were significantly more often functional in origin than those of the other two groups.     

Can reading disabilities be diagnosed without using intelligence tests?

Unlike conventional procedures, which use IQ in making diagnostic and eligibility decisions regarding learning disabilities, this demonstration study used listening comprehension and other reading-related tasks to make a differential diagnosis of reading disabilities. Tests of listening and reading comprehension were administered to 180 children from Grades 3 through 8. A regression equation was then derived to predict reading comprehension from listening comprehension. The regression equation was applied to the listening comprehension scores of seven children from Grades 3 to 8 who had reading difficulties, and their reading comprehension was predicted. Based on the discrepancy between their actual reading comprehension and the predicted reading comprehension, their reading difficulty was attributed to one of the following three factors: (a) poor decoding, (b) poor comprehension, or (c) a combination of poor decoding and poor comprehension. The validity of these diagnostic decisions was assessed by testing independently these children's word-decoding skill and reading speed. The results suggest that this diagnostic procedure has potential utility.     

How Should Reading Disabilities Be Operationalized? A Survey of Practicing School Psychologists

School psychologists' perceptions of how reading disabilities (RD) should be operationalized were examined and compared to those of journal editorial board members in the learning disabilities field ( Speece & Shekitka, 2002 ). Participants were practicing school psychologists drawn from the membership directory of the National Association of School Psychologists (NASP). The sample consisted of 549 participants and was generally representative of the demographic characteristics of NASP membership at large. Results indicated that over 75% of participants endorsed using treatment validity/response to intervention (RTI), cognitive processing, and phonemic awareness as components of RD operationalization. A large percentage (61.9%) also endorsed use of an IQ‐achievement discrepancy criterion. Statistically significant differences were found between the endorsements of this study's participants and those in the Speece and Shekitka (2002) study, with our participants reporting higher endorsement of RTI, cognitive processing, and IQ‐achievement discrepancy criteria.     

An investigation of the K-ABC,WISC-R,and W-JPB,part two,with learning disabled children

The purpose of this study was to examine the relationship of the Kaufman Assessment Battery for Children (K-ABC), the WISC-R, and the Woodcock-Johnson Psychoeducational Battery (W-JPB), Part Two, with children who experience learning disabilities. Correlational analyses were used to examine relationships among the WISC-R, K-ABC Mental Processing and Achievement scales, and the W-JPB Achievement scales. Thirty-four children with learning disabilities (mean age 8–11 years) received all three measures. Correlation coefficients indicated stronger and more consistent relationships between the WISC-R and W-JPB Achievement tests than between the K-ABC and W-JPB Achievement tests. Significant relationships between the WISC-R Full Scale IQ and the K-ABC Mental Processing Composite (MPC) revealed evidence of validity for this learning disabled sample. However, correlation coefficients among the K-ABC Achievement subtests and the W-JPB Achievement clusters indicated both convergent and discriminant validity. Thus, it is suggested that both the K-ABC MPC, for assessment of cognitive abilities, and the W-JPB Achievement clusters could be employed in discrepancy formulas for special education placement of children with learning disabilities.     

Differences required for significance between Wechsler verbal and performance IQs and WIAT subtests and composites: The predicted-achievement method

This paper provides tables of critical values for determining statistically significant discrepancies between Wechsler Verbal/Performance IQ and WIAT subtest and composite scores based on a predicted-achievement method. It is recommended that these tables be used when a statistically significant and diagnostically meaningful Verbal IQ-Performance IQ discrepancy exists rendering either of these IQs a better estimate of a student's ability than the Full Scale IQ. Issues regarding the use of discrepancy formulas in the assessment and diagnosis of learning disabilities are discussed, and basic considerations for using the critical values tables are provided.     

The Ability–Achievement Discrepancy: Does it Contribute to an Understanding of Learning Disabilities?

Federal legislation of the 1960s and 1970s extending educational services to learning disabled children contained a criterion requiring a severe discrepancy between an child's ability and achievement. Following a discussion of the historical context related to this decision, research related to discrepancy is reviewed using reading disabilities or dyslexia as the prototype. Topics examined include the relationship of IQ to various factors, including underlying cognitive weaknesses; varying IQ levels; stability of diagnosis; heterogeneity of the diagnostic category; genetic and neuroimaging findings; and appropriate standards of comparison. Research on the practical application of the discrepancy model is also reviewed. In general, there is little evidence to support its continued use. Three proposed alternatives are considered, and a possible model is offered that incorporates findings from research on diagnosis and intervention.     

Cognitive functioning as measured by the WISC-R: do children with learning disabilities have distinctive patterns of performance?

Patterns of performance on the Wechsler Intelligence Scale for Children-Revised (WISC-R) have been proposed as useful tools for the identification of children with learning disabilities (LD). However, most of the studies of WISC-R patterns in children with LD have been plagued by the lack of a typically achieving comparison group, by failure to measure individual patterns, and by the lack of a precise definition of LD. In an attempt to address these flaws and to assess the presence of patterns of performance on the WISC-R, we examined data from 121 children with typical achievement (TA), 143 children with reading disabilities (RD), and 100 children with a specific arithmetic disability (AD), ages 6 to 16 years. The results indicated that the RD and AD groups had significantly lower scores than the TA group on all the Verbal IQ subtests. Many of the children with AD and RD showed a significant difference between Verbal and Performance IQ scores, but so did many of the typically achieving children. Although there were some children with LD who showed the predicted patterns, typically, 65% or more of the children with LD did not. Furthermore, a proportion of the TA group-generally not significantly smaller than that of the RD and AD groups-showed discrepancy patterns as well. Our results indicate that the patterns of performance on intelligence tests are not reliable enough for the diagnosis of LD in individual children. Therefore, it might be more profitable to base the detection of an individual's LD on patterns of achievement test scores.     

Comparative functions of preschool learning style and IQ in predicting future academic performance

Early assessment programs frequently rely on intelligence tests for making predictions regarding children's future school performance. Unfortunately, IQ scores provide little information to those who must develop educational interventions tailored to the unique ways in which children respond to learning situations. Alternatively, measures of children's learning style focus on distinct patterns of learning-related behavior manifested in classroom settings. Each dimension of learning style is composed of observable skills that are potentially teachable or alterable through available instructional procedures. In order to examine the relative contributions of learning style dimensions, IQ, and their interactions to the prediction of subsequent performance, 100 kindergarten children were evaluated by teachers using the Study of Children's Learning Styles scale and were administered the Kuhlmann-Anderson Intelligence Test. Fifteen months later the children's first-grade achievement was determined through standardized tests and teacher-assigned grades in reading, language, and mathematics. Relationships between the predictor and criterion variables were studied through patterns of bivariate correlations, canonical variate loadings, and standardized regression weights. Although IQ was found the better predictor, learning styles accounted for appreciable and statistically significant proportions of the variability in later achievement. The learning style dimensions functioned differentially across areas of achievement to enhance overall prediction either by complementing or interacting with the predictions afforded by IQ. The results are examined in the light of earlier research on learning-related behavior.