Subtypes Of Learning-disabled Children Research Articles

Dysfunctional neural network of spatial working memory contributes to developmental dyscalculia

The underlying neural mechanisms of developmental dyscalculia (DD) are still far from being clearly understood. Even the behavioral processes that generate or influence this heterogeneous disorder are a matter of controversy. To date, the few studies examining functional brain activation in children with DD mainly focus on number and counting related tasks, whereas studies on more general cognitive domains that are involved in arithmetical development, such as working memory are virtually absent. There are several studies showing a close relationship between DD and spatial working memory [Camos, V. (2008). Low working memory capacity impedes both efficiency and learning of number transcoding in children. Journal of Experimental Child Psychology, 99(1), 37-57; McLean, J. F., & Hitch, G. J. (1999). Working memory impairments in children with specific arithmetic learning difficulties. Journal of Experimental Child Psychology, 74(3), 240-260; Rosselli, M., Matute, E., Pinto, N., & Ardila, A. (2006). Memory abilities in children with subtypes of dyscalculia. Developmental Neuropsychology, 30(3), 801-818; Siegel, L. S., & Ryan, E. B. (1989). The development of working memory in normally achieving and subtypes of learning disabled children. Child Development, 60(4), 973-980]. The relationship between these two mechanisms is still matter of debate, but this study follows the assumption that poor spatial working memory capacity may hinder the acquisition of spatial number representations in children with DD [Geary, D. C. (1993). Mathematical disabilities: Cognitive, neuropsychological, and genetic components. Psychological Bulletin, 114(2), 345-362; von Aster, M., & Shalev, R. S. (2007). Number development and developmental dyscalculia. Developmental Medicine and Child Neurology, 49(11), 868-873]. Using functional MRI the current study compares brain activity associated with spatial working memory processes in 8-10-year-old children with DD and normally achieving controls. Both groups showed significant spatial working memory related activity in a network including occipital and parietal regions. Children with DD showed weaker neural activation compared to the control group during a spatial working memory task in the right intraparietal sulcus (IPS), the right insula and the right inferior frontal lobe. Performance tests outside the scanner showed impaired working memory proficiency in children with DD. Bringing behavioral performance and neural activity together we found significant correlations of right IPS activity with performance on the verbal digit span forward and the spatial Corsi Block Tapping test. Our findings demonstrate for the first time an involvement of spatial working memory processes in the neural underpinnings of DD. These poor spatial working memory processes may inhibit the formation of spatial number representations (mental numberline) as well as the storage and retrieval of arithmetical facts.

Social biases toward children with speech and language impairments: A correlative causal model of language limitations

ABSTRACTThis study explores adults' attitudes toward children with limited linguistic competency. Four groups of adult judges participated in this study: kindergarten teachers, women matched for age and education level with the teachers, undergraduate college students, and speech-language pathologists. The judges listened to audiotaped samples of preschool children's speech. Two triads of children were formed, matched for age, gender, and intelligence, but differing in communication abilities. The adults responded to questionnaire items addressing child attributes (e.g., intelligence, social maturity) and parental attributes (e.g., education level, SES). Systematic biases were revealed toward children with limited communication abilities. The biases are interpreted as reflective of adults' expectations for children's language.It is argued that adults call upon a correlative causal model of language acquisition to interpret individual differences in children's language abilities. Negative social and academic consequences of such misinterpretations are discussed. The visual similarity of the error to the target word was also determined. The RD group at all ages produced significantly fewer phonologically accurate misspellings than the children with normal achievement scores, whether the constrained or the unconstrained scoring system was used. The AD-poor spellers and the RD group produced significantly fewer phonologically constrained, accurate misspellings than the NA group. Using the unconstrained measure, the AD-poor spellers at the youngest age level displayed as much difficulty using rudimentary sound-symbol conversion rules as the RD group, while at the older age levels, they did as well as the NA group. AD-good spellers performed as well as the NA group on both measures at all age levels. Children who were good readers and spellers (Good RS) were compared with children who were poor readers and spellers (Poor RS) and with children who were good readers and poor spellers (Mixed RS). Mixed RS produced significantly more phonologically and visually accurate misspellings than Poor RS. In summary, subtypes of learning-disabled children use spelling strategies that are significantly different from each other. RD children have the most difficulty acquiring the knowledge of soundspelling correspondence rules that are necessary for English spelling skills. The performance of AD children depends on the complexity of the scoring system, age, and spelling ability. Those students whose knowledge of sound-spelling correspondence rules is sufficiently well developed for reading but not for spelling (good readers/poor spellers) develop their phonetic skills more slowly than the good readers/good spellers. The understanding and use of phonological rules varies according to the subtype of learning disability, with children with a reading disability performing the most poorly at all age levels.

Visual and phonological spelling errors in subtypes of children with learning disabilities

ABSTRACTThis study investigated the hypothesis that children with a reading disability understand and use sound-spelling correspondence rules less frequently in spelling than children with other learning disabilities and normally achieving children. To test this hypothesis, spelling errors of children between the ages of 6 and 16 with a reading disability (RD), an arithmetic disability (AD), and normally achieving children (NA) were examined. Two groups of children with an arithmetic disability were included: those with good spelling skills (AD-good), and those with poor spelling skills (AD-poor). The accuracy of the spelling errors according to sound-spelling correspondence rules (phonological accuracy) of the children was determined using both a constrained system (inclusion of position cues) and an unconstrained system (in which positional cues were irrelevant). The visual similarity of the error to the target word was also determined. The RD group at all ages produced significantly fewer phonologically accurate misspellings than the children with normal achievement scores, whether the constrained or the unconstrained scoring system was used. The AD-poor spellers and the RD group produced significantly fewer phonologically constrained, accurate misspellings than the NA group. Using the unconstrained measure, the AD-poor spellers at the youngest age level displayed as much difficulty using rudimentary sound-symbol conversion rules as the RD group, while at the older age levels, they did as well as the NA group. AD-good spellers performed as well as the NA group on both measures at all age levels. Children who were good readers and spellers (Good RS) were compared with children who were poor readers and spellers (Poor RS) and with children who were good readers and poor spellers (Mixed RS). Mixed RS produced significantly more phonologically and visually accurate misspellings than Poor RS. In summary, subtypes of learning-disabled children use spelling strategies that are significantly different from each other. RD children have the most difficulty acquiring the knowledge of soundspelling correspondence rules that are necessary for English spelling skills. The performance of AD children depends on the complexity of the scoring system, age, and spelling ability. Those students whose knowledge of sound-spelling correspondence rules is sufficiently well developed for reading but not for spelling (good readers/poor spellers) develop their phonetic skills more slowly than the good readers/good spellers. The understanding and use of phonological rules varies according to the subtype of learning disability, with children with a reading disability performing the most poorly at all age levels.

The Development of Working Memory in Normally Achieving and Subtypes of Learning Disabled Children

Working memory has been proposed as an important component of reading and arithmetic skills. The development of working memory was studied in normally achieving and subtypes of learning disabled children. The performance of reading disabled (RD), arithmetic disabled (ARITHD), and attentional deficit disordered (ADD) children, age 7-13, was compared to normal achievers (NA) on 2 working memory tasks, 1 involving sentences and the other involving counting. There was a significant growth of working memory as a function of age. In addition, the RD children had significantly lower scores on both tasks. The ARITHD children had significantly lower scores only on the Working Memory--Counting task, and the ADD group had scores similar to the normally achieving children except at the youngest age level in the Working Memory--Sentences task. Thus, a reading disability appears to involve a generalized deficit in working memory. Children with an arithmetic disability do not have a generalized language deficit but have a specific working memory deficit in relation to processing numerical information. As children with ADD did not have deficits in these tasks, working memory may not have significant attentional components. An important component of the development of reading and computational arithmetic skills appears to be the growth of working memory for language and numerical information.

Psychosocial functioning of learning disabled children: Replicability of statistically derived subtypes.

The PIC scores of 132 learning-disabled children between the ages of 6 and 12 years were investigated using Q-factor analysis, four hierarchical-agglomerative clustering techniques, and one iterative partitioning clustering technique. Results revealed excellent correspondence between the subtypes derived by all grouping methods in terms of both misclassifications and mean PIC profile similarity of the subtypes across techniques. The mean PIC profile of one subtype indicated normal psychosocial adjustment; a second subtype exhibited evidence of significant internalized psychopathology; a third subtype had a mean PIC profile suggestive of externalized psychosocial maladjustment. These subtypes were virtually identical to three subtypes reported by Porter and Rourke (1985) in another study of learning-disabled children. The results indicate that learning-disabled children comprise a heterogeneous population in terms of psychosocial functioning and that subtypes of learning-disabled children with similar patterns of socioemotional adjustment can be recovered reliably from this population across samples and statistical grouping techniques.

Psychosocial functioning of learning-disabled children: replicability of statistically derived subtypes.

The PIC scores of 132 learning-disabled children between the ages of 6 and 12 years were investigated using Q-factor analysis, four hierarchical-agglomerative clustering techniques, and one iterative partitioning clustering technique. Results revealed excellent correspondence between the subtypes derived by all grouping methods in terms of both misclassifications and mean PIC profile similarity of the subtypes across techniques. The mean PIC profile of one subtype indicated normal psychosocial adjustment; a second subtype exhibited evidence of significant internalized psychopathology; a third subtype had a mean PIC profile suggestive of externalized psychosocial maladjustment. These subtypes were virtually identical to three subtypes reported by Porter and Rourke (1985) in another study of learning-disabled children. The results indicate that learning-disabled children comprise a heterogeneous population in terms of psychosocial functioning and that subtypes of learning-disabled children with similar patterns of socioemotional adjustment can be recovered reliably from this population across samples and statistical grouping techniques.

Academic consequences and longitudinal stability of behavioral subtypes of learning disabled children.

Academic consequences and longitudinal stability of behavioral subtypes of learning disabled children.

Academic consequences and longitudinal stability of behavioral subtypes of learning disabled children.

Academic consequences and longitudinal stability of behavioral subtypes of learning disabled children.

Classification and validation of behavioral subtypes of learning-disabled children.

Classification and validation of behavioral subtypes of learning-disabled children.

The Search for Subtypes of Specific Learning Disability

This month's Topical Review discusses recent research that has attempted to divide the general population of learning-disabled children into a variety of different subtypes. The research is important because it is the first sustained attempt to deal with one of the most troublesome problems in the field: the heterogeneity of learning-disabled children. Past failure to adequately conceptualize the variability within the LD population has produced heated debates over the “nature” of learning disabilities and has limited progress toward adequate diagnosis and treatment. Although we are still a long way from having an adequate taxonomy of learning disabilities subtypes, the research presented in this review certainly constitutes one of the first steps toward the attainment of that goal.---JKT This paper reviews and evaluates the current research on subtypes of learning-disabled children. Early research on LD subtypes used a clinical inferential approach to subdivide heterogeneous samples of children into various syndromes. More recently, several studies have appeared in which multivariate classification techniques have been used to group children empirically. Collectively, the evidence argues against a “single syndrome” theory of learning disability and demonstrates the feasibility of creating more homogeneous diagnostic groups within this broad and ill-defined category of exceptional children.

Neuropsychological Implications for Teaching the Learning Disabled

Since the early seventies many advances have been made in our understanding of brain-behavior relationships in children. Much of this knowledge can be attributed largely to the development of sophisticated research techniques and methodologies. The result of this research has led primarily to more reliable assessment and evaluation procedures that differentially diagnose neuropsychologically-based learning problems from those learning problems due to other factors. This special section on neuropsychology was developed from our recognition that the provision of appropriate education services to children with learning disorders must incorporate the recent insights gained about neuropsychological functioning. Only through the integration of behavioral, educational, and neuropsychological knowledge will children with learning problems be given the opportunity to achieve to their maximum capability in the classroom. In planning the contents of this special section for the journal of Learning Disabilities, our intent was to provide the reader with a neuropsychological perspective on educational, assessment, and intervention issues related to the teaching of learning-disabled children. Specifically, Gaddes discusses the neuropsychological theory of behavior and provides a rationale for the importance and validity of including a neuropsychological perspective in education diagnosis and treatment of learning disabilities. Obrzut and Hynd provide neurobiological and psychophysiological evidence as validity of how neurodevelopmental deficits contribute to learning disorders in children. Hartlage and Telzrow discuss how assessment data which derive a profile of neuropsychological strengths and weaknesses can be utilized as the basis for individualizing instructional programs for learning-disabled children. Fisk and Rourke provide evidence that demonstrates the reliability and internal validity for the classification of homogeneous subtypes of learning-disabled children with respect to their patterns of neuropsychological abilities and deficits. Obrzut and Hynd conclude the feature by suggesting that professionals with a neuropsychologial perspective working within an educational environment can provide a more fruitful integration of behavioral and educational data, as well as more appropriate and relevant educational intervention.

Central processing deficiencies in children: toward a developmental neuropsychological model.

Abstract A recent theoretical position (Goldberg & Costa, 1981) is employed as a framework for a neurodevelopmental model of central processing deficiencies in children. The model, which emphasizes differences between right-hemisphere and left-hemisphere systems, is shown to embrace a wide variety of behavioural phenomena that have been observed in normal children and in various subtypes of learning-disabled children. Dynamic factors operative within the development of both normal and disabled learning are addressed and incorporated.