Interrelationships between Reading Disability and Attention-Deficit/Hyperactivity Disorder

Evidence from a number of investigations suggests a considerable overlap between reading disability (RD) and attention deficit-hyperactivity disorder (ADHD). We investigate the relationship between RD and ADHD in a cohort of 186 children 7.5–9.5 years of age, recruited explicitly to address classification and definitional issues in these disorders. Using multivariate methods, we examine the hypothesis that RD and ADHD represent separate diagnostic entities that frequently co-occur in the same individual. The results suggest that RD is characterized by deficits within the language system, in particular a subcomponent within that system, phonological processing; in contrast, such linguistic deficits are not characteristic of ADHD unless ADHD is associated with RD. When children with both RD and ADHD are examined, both the linguistic deficits associated with RD and the behavioral characteristics associated with ADHD are apparent, but these deficits are not synergistic. We conclude that RD and ADHD represent separate disorders that frequently co-occur.     

Components of IQ Scores Across Levels of Measured Ability

Forty-three (43) students from the Talent Identification Program's Summer Residential Program living in North Carolina took the Wechsler Intelligence Scale for Children—Revised (WISC-R; Wechsler, 1974) during the program. The test was also administered to 50 other North Carolina Students who qualified for the SRP but did not attend, as well as 34 students who had not been identified as gifted. The scores were evaluated for normative and idiographic strengths and weaknesses on the 12 subtests of the WISC-R. The idiographic differences were calculated by comparison against the average score of only the 6 subtests in the same subscale of the test (Verbal or Performance) as well as against all 12 subtests on the test. It was found by means of the former comparisons that the gifted students showed significantly more idiographic strengths on the Verbal scales and weaknesses on the Performance scales than the academically competent sample.     

Paired-Associate Learning in Attention-Deficit/Hyperactivity Disorder as a Function of Hyperactivity-Impulsivity and Oppositional Defiant Disorder

A paired-associate learning (PAL) test was administered to 22 community volunteers without disruptive disorders and 197 children (7.5–13.5 years-old) presenting with the inattentive and combined subtypes of attention-deficit/hyperactivity disorder (ADHD) either in combination with or without oppositional defiant disorder (ODD). Participants were screened for learning disorders. In comparison to non-ADHD participants, children with ADHD achieved worse PAL and made errors rated as more acoustically and less semantically similar to the correct paired associates. These deficits were not related to hyperactivity–impulsivity or comorbid ODD. These results suggest that ADHD children are less competent at PAL and use less efficient learning strategies than their non-ADHD peers.     

COGNITIVE PROFILES OF READING-DISABLED CHILDREN:

Abstract— A comprehensive cognitive appraisal of elementary school children with learning disabilities showed that within the language sphere, deficits associated with reading disability are selective. Phonological deficits consistently accompany reading problems whether they occur in relatively pure form or in the presence of coexisting attention deficit or arithmetic disability. Although reading-disabled children were also deficient in production of morphologically related forms, this difficulty stemmed in large part from the same weakness in the phonological component that underlies reading disability. In contrast, tests of syntactic knowledge did not distinguish reading-disabled children from those with other cognitive disabilities, nor from normal children after covarying for intelligence.     

Use of a common software system for collaborative clinical research on attentional processes in schizophrenia and ADHD

MacArthur Network III, consisting of five nodes (locations) and over 100 investigators, was formed in 1983 to conduct collaborative clinical research on risk and protective factors associated with psychiatric disorders. The common measurement of attentional dysfunction associated with two specific disorders (schizophrenia and attention deficit-hyperactivity disorder) was a goal of a subgroup of 11 Network III investigators. In this paper, the experiences with five approaches for implementing common protocols on laboratory computers for collaborative clinical research are described. The reasons for selecting the approach provided by Schneider’s (1988) MEL system are presented and discussed.     

Functional neuroimaging studies of reading and reading disability (developmental dyslexia)

Converging evidence from a number of neuroimaging studies, including our own, suggest that fluent word identification in reading is related to the functional integrity of two consolidated left hemisphere (LH) posterior systems: a dorsal (temporo-parietal) circuit and a ventral (occipito-temporal) circuit. This posterior system is functionally disrupted in developmental dyslexia. Reading disabled readers, relative to nonimpaired readers, demonstrate heightened reliance on both inferior frontal and right hemisphere posterior regions, presumably in compensation for the LH posterior difficulties. We propose a neurobiological account suggesting that for normally developing readers the dorsal circuit predominates at first, and is associated with analytic processing necessary for learning to integrate orthographic features with phonological and lexical-semantic features of printed words. The ventral circuit constitutes a fast, late-developing, word identification system which underlies fluent word recognition in skilled readers.     

Longitudinal models of developmental dynamics between reading and cognition from childhood to adolescence

The authors applied linear dynamic models to longitudinal data to examine the dynamics of reading and cognition from 1st to 12th grade. They used longitudinal data (N=445) from the Connecticut Longitudinal Study (S. E. Shaywitz, B. A. Shaywitz, J. M. Fletcher, & M. D. Escobar, 1990) to map the dynamic interrelations of various scales of the Wechsler Intelligence Scales for Children--Revised (i.e., Full, Performance, and Verbal) and specific markers of the Woodcock-Johnson Psycho-Educational Battery--Revised reading cluster (i.e., Letter-Word ID, Decoding, and Comprehension). The results of these analyses indicate that (a) there is a positive dynamic relation between reading and cognition across the selected age range; (b) this dynamic relation is symbiotic, with positive influences in both directions; (c) the influence from cognition to reading is stronger when considering the Wechsler Intelligence Scales for Children Performance--Revised Performance scale and weaker with the Verbal scale; (d) when examining the different Reading subtests, the influences from cognition are more apparent for Letter-Word ID and Comprehension and are less perceptible for Decoding; and (e) the dynamics of reading and cognition appear to be of stronger magnitude during 1st to 3rd grade, less strong during 4th to 8th grade, and weaker from 9th to 12th grade.     

Neural Mechanisms in Dyslexia

ABSTRACT— Within the last two decades, evidence from many laboratories has converged to indicate the cognitive basis for dyslexia: Dyslexia is a disorder within the language system and, more specifically, within a particular subcomponent of that system, phonological processing. Converging evidence from a number of laboratories using functional brain imaging indicates that there is a disruption of left-hemisphere posterior neural systems in child and adult dyslexic readers when they perform reading tasks. The discovery of a disruption in the neural systems serving reading has significant implications for the acceptance of dyslexia as a valid disorder—a necessary condition for its identification and treatment. Brain-imaging findings provide, for the first time, convincing, irrefutable evidence that what has been considered a hidden disability is "real," and these findings have practical implications for the provision of accommodations, a critical component of management for older children and young adults attending postsecondary and graduate programs. The utilization of advances in neuroscience to inform educational policy and practices provides an exciting example of translational science being used for the public good.     

Yale Children's Inventory (YCI): An instrument to assess children with attentional deficits and learning disabilities I. Scale development and psychometric properties

The Yale Children's Inventory (YCI), a parent based rating scale, and the scales derived from it have been developed to identify and measure multiple dimensions of learning disabilities with particular emphasis on attentional deficits. Scale construction was based on factor analytic procedures. Measures of internal consistency, test retest reliability, and coefficients of congruence support the reliability and stability of the 11 scales. A discriminant function classified normal and learning disabled children with a relatively high rate of accuracy. The relationship and content of the three relevant YCI scales were compared to the DSM-III diagnostic categories for ADD. As operationalized, DSM-III criteria for hyperactivity formed a cohesive factor, while criteria for attention and impulsivity were not distinguishable from each other since they loaded together on a single factor. In contrast, the equivalent YCI scales for attention, impulsivity, and hyperactivity were found to be distinct.     

The angular gyrus in developmental dyslexia: task-specific differences in functional connectivity within posterior cortex

Converging evidence from neuroimaging studies of developmental dyslexia reveals dysfunction at posterior brain regions centered in and around the angular gyrus in the left hemisphere. We examined functional connectivity (covariance) between the angular gyrus and related occipital and temporal lobe sites, across a series of print tasks that systematically varied demands on phonological assembly. Results indicate that for dyslexic readers a disruption in functional connectivity in the language-dominant left hemisphere is confined to those tasks that make explicit demands on assembly. In contrast, on print tasks that do not require phonological assembly, functional connectivity is strong for both dyslexic and nonimpaired readers. The findings support the view that neurobiological anomalies in developmental dyslexia are largely confined to the phonological-processing domain. In addition, the findings suggest that right-hemisphere posterior regions serve a compensatory role in mediating phonological performance in dyslexic readers.