Diagnosis and treatment of reading disabilities based on the component model of reading: an alternative to the discrepancy model of LD.

Currently, learning disabilities (LD) are diagnosed on the basis of the discrepancy between students' IQ and reading achievement scores. Students diagnosed with LD often receive remedial instruction in resource rooms. The available evidence suggests that the educational policy based on this discrepancy model has not yielded satisfactory results. This has led researchers to try other paradigms, such as the component model and response to intervention, for dealing with children with reading disabilities. The component model of reading (CMR) described in the present article identifies the reading component that is the source of reading difficulty and targets instruction at that component. Study 1 describes the CMR and reports on its validity. Study 2 describes the successful outcome of a 7-year CMR-based reading instruction program. Compared to the discrepancy model, the CMR has demonstrated several advantages.

Developmental dyslexia: Is it different from other forms of reading disability?

A controversy whether developmental dyslexia is qualitatively different from other forms of reading disability has existed among reading specialists for many years. In the present study, the hypothesis that the etiology of dyslexia is different from that of other forms of reading disability because of differences in the components that malfunction was tested. A number of studies have shown that the two components that contribute to a large proportion of variance in reading are decoding and comprehension. It is, therefore, possible that a breakdown of different components could lead to different forms of disabilities. College students who were poor readers were assigned to two groups on the basis of their IQ. Conforming to the traditional criterion of dyslexia, those who had an IQ of 95 and above were considered as dyslexic. Those who had an IQ of 85 or below were placed in the Nonspecific Reading-Disabled group. These two groups of poor readers and a group of normal readers were administered a large number of reading-related tests. It was found that the two reading-disabled groups differed from each other in six of the seven areas assessed. There was very little overlap of scores between the two groups in these areas. The results were interpreted to suggest that poor decoding skill is the etiology of developmental dyslexia and that it differs from other forms of reading disability which are caused by generalized cognitive deficits.

Is there a visual dyslexia.

Traditionally, it has been speculated that weaknesses in the visual processing of cognitive aspects of the written word could lead to reading problems, and if so, such a condition would constitute a subtype of developmental dyslexia. This putative subtype has been referred to as visual dyslexia. In this article, the role of cognitive deficits that are visual in nature as a potential etiological factor of developmental dyslexia is examined. Following a brief history of the study of dyslexia, a critique of studies of visual dyslexia is presented. Subsequently, the nature of the visual processes involved in word- recognition is examined. Finally, three research studies that assessed the contribution of visual memory to word-recognition are presented. It is concluded that, even though defects in the physiological aspects of visual processing can lead to reading difficulties, at present little convincing evidence is available to conclude that a subtype of dyslexia caused by cognitive deficits associated with visual processing of information exists.

A decade of research with dyslexic college students: A summary of findings.

The major findings of several research projects that investigated dyslexic college students are summarized in this paper. Consistent findings of these investigations led to the following conclusions. 1) Developmental dyslexia is a syndrome made up of the following four symptoms: slow rate of reading, error-prone oral reading, poor written spelling, and grammatically incorrect writing; 2) all these symptoms could be traced to a poor mastery of the grapheme-phoneme relational rules; 3) developmental dyslexia can be found in subjects who appear to have adequate oral language skills; 4) ex-dyslexics who appear to be "poor spellers but good readers" have subtle reading deficits; and 5) the 20 dyslexic subjects investigated appear to constitute a homogeneous group which raises questions regarding dyslexia subtypes.

Is there a thing called dyslexia?

A controversy whether developmental dyslexia is qualitatively different from other forms of reading disability has existed among reading specialists for many years because poor readers, regardless of the labels attached to them, resemble each other symptomatically (i.e., in reading achievement). For this reason, it is difficult to establish a priori criteria based on symptoms to identify dyslexia and compare it with other forms of reading disability. One possible solution to this impasse is to see if poor readers differ in the etiology of their reading disability and, if they do, then to see whether one group of poor readers fits the traditional definition of dyslexia. This strategy was adopted in the present study. In this paper, it was hypothesized that the etiology of dyslexia is different from that of other forms of reading disability because there is a difference in the components that malfunction in dyslexia and other forms of reading disability. Studies have shown that the two components that account for a large proportion of variance in reading are decoding and comprehension. Previous studies also indicate that dyslexic children are deficient in decoding skills but not necessarily in comprehension. In this study, reading-disabled children were divided into two groups on the basis of their listening comprehension. Children whose listening comprehension was at or above grade level were placed in one group; poor readers with below-grade-level listening comprehension were placed in the second group. Both groups, however, were matched for reading comprehension. The two groups and a control group of normal readers were administered a number of tasks that were designed to assess the efficiency of the components of reading. It was found that poor readers with normal listening comprehension were deficient in tasks that involved grapheme-phoneme conversion (Component I, decoding). When tested on tasks that minimized decoding requirements, their reading comprehension was comparable to that of normal readers. In contrast, the group with sub-average listening comprehension was poor in measures of reading comprehension, even when decoding requirements were minimal. With the exception of very few children, this group also had adequate decoding skills. Because poor readers with normal listening comprehension had average or above average IQ, they conform to the traditional definition of dyslexia. Poor readers with below average listening comprehension had below average IQ and could be considered as "general reading backward." It was, therefore, concluded that the etiology of developmental dyslexia is different from that of general reading backwardness.

A cognitive tool to diagnose predominantly inattentive ADHD behavior.

Poor performance on tests of reading comprehension could be the result of weak word-recognition skills, inconsistent attention (ADD), or a combination of the two. Identifying the source of the reading disability (RD) reliably has been difficult because inconsistent attention interferes with reading and weak word recognition skill makes attention wander. The situation is further complicated by the fact that there are no objective diagnostic tests for ADD (Breggin, 1998; Diller, 1998). We proposed a new model of differential diagnosis of ADHD-I/RD and field-tested its utility in two studies. The new diagnostic procedure utilizes intra-individual differences seen in the performance of at-risk learners on tasks related to reading that vary in the degree of sustained attention required for successful performance. The hypothesis is that children whose attention is inconsistent would perform more poorly on tests such as listening comprehension, which require sustained attention, than on tests such as reading comprehension, which are more tolerant of inattention. Such differences will not be seen in the test scores of children who have only a reading disability because their performance on reading tests is determined more by the difficulty level of the tests than by the sensitivity of the tests to attention. The validity of this new model was evaluated by determining the relationship between differences seen in the scores of tests that differ in their attention requirement and the degree of inconsistency in sustained attention as measured by Conners' CPT. The results of the two studies indicate this to be a viable approach. The results of the second study are presented in this report.

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.

Not all reading disabilities are alike.

In this article, reading disability is defined broadly to refer to below-average achievement in reading comprehension as assessed by a standardized test. With our research we tried to answer the question of whether all children with reading disability share a common etiology of deficient phonology, or constitute heterogeneous groups. The answer to this question was sought in four studies that examined reading disabilities from the perspective of componential skills of reading. In Part 1, the results of the first study are reported. A principal-components analysis of the performance of 139 children from Grades 3, 4, and 6 on reading-related tasks yielded two factors: decoding and comprehension. However, factor analyses conducted for each grade separately indicated that orthographic skill and processing speed could possibly constitute a third component. The orthography-speed factor emerged as a factor only in the 6th grade. Part 2 of this article reports the findings of three studies that analyzed the componential skills profiles of poor readers. It was found that the poor readers constituted heterogeneous groups and that four different types of poor readers could be identified with deficiency in any one of the following skills: (a) decoding only, (b) comprehension only, (c) a combination of decoding and comprehension, and (d) a combination of orthographic processing and reading speed. It was also found that the criteria used in selecting poor readers influenced the distribution of the ratio of the four types of poor readers within any given group.

Separating genuine cases of reading disability from reading deficits caused by predominantly inattentive ADHD behavior.

Conventional methods of differentiating reading disability (RD) caused by deficits in decoding skills or comprehension from poor reading performance caused by inconsistent attention associated with attention-deficit/hyperactivity disorder (ADHD) have produced equivocal results. This study presents a model of differential diagnosis of attentional problems and RD that differs from these conventional approaches. The new diagnostic procedure uses intraindividual differences seen in the performance of at-risk learners on tasks related to reading that vary in their sensitivity to the sustained attention required for successful performance. The hypothesis is that children with inconsistent attention would perform more poorly on tests that require sustained attention, such as listening comprehension, than on tests that are more tolerant of inattention, such as reading comprehension. Such differences would not be seen in the test scores of children who have only RD, because their performance is determined more by the difficulty level of the reading tests than by the degree of sensitivity of the task to attention. The validity of this new model was evaluated by determining the capability of the differences seen in the scores of tests that differ in their sensitivity to sustained attention to predict the degree of inconsistency in sustained attention as measured by a continuous performance test. The data obtained from 39 children who are at risk for RD suggest that this is a viable model.

The paradoxical relationship between intelligence and reading disability.

Specific reading disability or developmental dyslexia is a condition wherein an individual with average or superior intelligence does not acquire normal reading skills. This paper provides a tentative explanation of the paradoxical relationship between the reading disability and intelligence. Study of 15 dyslexic college students showed that they were deficient in grapheme-phoneme conversion and that the decoding skill could be an autonomous, specific ability that is independent of the "g" factor as expressed in terms of IQ. The decoding skill appears to be a subroutine and may, in dyslexia, operate as a limiting factor that affects reading comprehension.

Dyslexia, an imbalance in cerebral information-processing strategies.

Reading ability seems to involve analytic-sequential processing of selected letters and a holistic-simultaneous perception of the salient features of the entire word. The dyslexic child, being normal in intelligence, is most likely deficient in either one of the two processes while being normal in the other. To test this hypothesis, 28 reading disabled children, on the basis of the nature of errors made in a writing from dictation task, were divided into groups: analytic-sequential deficient and holistic-simultaneous deficient. Further testing showed that the first group was poor in processing a sequence of digits but normal on holistic-simultaneous memory tasks. The opposite pattern of performance was shown by the second group. A control group of 14 normal readers did not show such an imbalance.

Directional scanning and cerebral asymmetries in processing visual stimuli.

A perceptual exploration task involving three horizontal linear arrays of stimuli was administered to 167 children ranging in age from 3 to 7 yr. It was found that the well organized, predominantly right-to-left responses of very young children were eventually replaced by left-to-right patterns. A tachistoscopic test showed that Ss who gave right-to-left responses to the linear arrays showed hemispheric asymmetry of perception. The results were interpreted as supporting the view that directional response tendencies are related to hemispheric asymmetry.

Componential model of reading (CMR): validation studies.

The three current models of identifying learning disabilities: discrepancy model, RtI, and Componential Model of reading are discussed in terms of their utility.

Cognitive component of componential model of reading applied to different orthographies.

Whether the simple view of reading (SVR) as incorporated in the componential model of reading (CMR) is applicable to other orthographies than English was explored in this study. Spanish, with transparent orthography and Chinese, with opaque orthography were selected because of their diverse characteristics. The first part reports a study of students from grades 2 and 3, whose home language and medium of instruction was Spanish, and were administered tests of decoding, listening, and reading comprehension. A comparison group of 49 children from Grade 2, 54 children from Grade 3, and 55 children from Grade 4, whose home language and instruction was English, were also administered tests of decoding, listening, and reading comprehension. Multiple regression analysis showed that approximately 60% of the variance in reading comprehension of Spanish participants and 50% of the variance in reading comprehension of English participants were explained by decoding and listening comprehension. Furthermore, the performance of third grade Spanish participants resembled that of fourth grade English-speaking participants. In the second study, 102 Chinese students from Grade 2 and 106 students from Grade 4 were administered tasks of Chinese character recognition, reading fluency, listening, and reading comprehension. Multiple regression analyses showed character recognition and listening comprehension accounted for 25% and 42% of the variance in Chinese reading comprehension at Grades 2 and 4 respectively. These results indicate that the simple view of reading is applicable to writing systems other than that of English.

A neuropsychological Key approach to diagnosis and remediation of learning disabilities.

Described a new approach in reaching clinical decisions with regard to learning disabled children. The method emphasizes a systematic deductive procedure and is presented in the form of a Key. The rationale for the diagnostic and remedial decisions reached at every node of the Key is explained and is supported by data derived from clinical and experimental studies in psychology and neurology.