Learning disability and hyperactivity: Deficits in selective attention

Differences in performance on a variety of cognitive measures and differences in patterns of ability between learning disabled (LD) and nonlearning disabled (non-LD) children were examined. Younger and older LD and non-LD children were administered tests of central and incidental learning and selective attention. Teacher ratings of classroom hyperactivity were also examined. LD children, particularly the younger ones, performed significantly more poorly than non-LD children on both attention/memory tasks. Performance on the two tasks was consistently interrelated for the non-LD children and less consistently so for the LD subjects. Hyperactivity was also related to poorer performance on the cognitive measures. Results are discussed in terms of components of selective attention.     

An examination of encoding and retrieval processes in reading disabled children

A choice reaction time experiment was performed in order to assess the information processing characteristics of 12-year-old reading disabled children. Eight reading disabled children were compared to a sample of nondisabled readers. The stimuli consisted of consonants presented in three memory load conditions. A Stimulus Quality manipulation was included in the design in order to assess the encoding process. The results of the research indicated that the rate of encoding differed between disabled and nondisabled readers. In addition, support for the hypothesis that disabled and nondisabled readers do not differ in terms of central processes was also obtained.     

学习不良儿童的策略信念与理解水平

使用结构访谈法对120名儿童(其中学习不良儿童60名)的策略信念与策略理解水平进行了研究。结果显示:学习不良儿童组与一般儿童组的差异更多体现在对具体策略的元认知因果解释水平上,他们更多持有较低水平的“信息获得”解释,而对照组儿童则更多持有较高水平的“信息加工”解释,提示对策略理解水平的差异可能是导致学习不良儿童难以将新学到的策略主动应用到其它情景中去的一个重要原因。     

Numerical and arithmetical cognition: a longitudinal study of process and concept deficits in children with learning disability

Based on the stability and level of performance on standard achievement tests in first and second grade (mean age in first grade = 82 months), children with IQ scores in the low-average to high-average range were classified as learning disabled (LD) in mathematics (MD), reading (RD), or both (MD/RD). These children (n = 42), a group of children who showed variable achievement test performance across grades (n = 16), and a control group of academically normal peers (n = 35) were administered a series of experimental and psychometric tasks. The tasks assessed number comprehension and production skills, counting knowledge, arithmetic skills, working memory, the ease of activation of phonetic representations of words and numbers, and spatial abilities. The children with variable achievement test performance did not differ from the academically normal children in any cognitive domain, whereas the children in the LD groups showed specific patterns of cognitive deficit, above and beyond the influence of IQ. Discussion focuses on the similarities and differences across the groups of LD children.     

Age-related differences in learning disabled and skilled readers' working memory

This study determines whether age-related deficits in learning disabled (LD) readers' working memory performance reflect delays in retrieval efficiency and/or storage capacity. The study compared LD and skilled readers' working memory performance (N=226) across four age groups (7, 10, 13, and 20) for phonological, visual-spatial, and semantic information under initial (non-cued), gain (cues that bring performance to an asymptotic level), and maintenance conditions (asymptotic conditions without cues). The important results were that LD readers' working memory performance was inferior to skilled readers on verbal and visual-spatial working memory tasks across all age groups and these differences increased on gain and maintenance conditions when compared to initial conditions. These reading group differences remained when age, reading, and mathematics were partialed from the analysis. The results support a general capacity explanation of reading group differences that is not totally dependent on reading skill. These differences in capacity reflect demands placed on both the accessing of new information and the maintenance of old information that extend beyond the phonological system.     

Working memory failures in children with arithmetical difficulties.

A large body of literature has examined the relationship between working memory and arithmetic achievement, but results are still ambiguous. To examine this relationship, we compared the performance of third and fifth graders with arithmetic difficulties (AD) and controls of the same age, grade, and verbal intelligence on a battery of working memory tasks, differentiating between different aspects of working memory. Children with AD scored significantly lower on active working memory tasks requiring manipulation of the to-be-recalled information (Listening Completion task, Corsi Span Backwards, Digit Backwards), but not in passive working memory tasks, requiring the recall of information in the same format in which it had been presented (Digit, Word, and Corsi Forwards Span tasks), nor in tasks involving word processing (word articulation rate, forwards and backwards word spans). A regression analysis showed that the best predictors of differences between AD children and the control group were the Corsi Span Backwards, the Listening Completion task, and the rate of articulation of pseudowords. The analysis of strategies used by children in mental calculation revealed the greater tendency of children with AD to rely on more primitive strategies: finger use never appeared as the most frequent strategy in skilled children, whereas it was the most used strategy in children with AD. Verbal and visual strategies appeared associated with successful performance in third graders, but in fifth grade, the most successful strategy was verbalization.     

Working Memory Failures in Children with Arithmetical Difficulties

A large body of literature has examined the relationship between working memory and arithmetic achievement, but results are still ambiguous. To examine this relationship, we compared the performance of third and fifth graders with arithmetic difficulties (AD) and controls of the same age, grade, and verbal intelligence on a battery of working memory tasks, differentiating between different aspects of working memory. Children with AD scored significantly lower on active working memory tasks requiring manipulation of the to-be-recalled information (Listening Completion task, Corsi Span Backwards, Digit Backwards), but not in passive working memory tasks, requiring the recall of information in the same format in which it had been presented (Digit, Word, and Corsi Forwards Span tasks), nor in tasks involving word processing (word articulation rate, forwards and backwards word spans). A regression analysis showed that the best predictors of differences between AD children and the control group were the Corsi Span Backwards, the Listening Completion task, and the rate of articulation of pseudowords. The analysis of strategies used by children in mental calculation revealed the greater tendency of children with AD to rely on more primitive strategies: finger use never appeared as the most frequent strategy in skilled children, whereas it was the most used strategy in children with AD. Verbal and visual strategies appeared associated with successful performance in third graders, but in fifth grade, the most successful strategy was verbalization.     

Selective attention in children with learning disabilities.

49 children, aged 11 to 14 yr., a learning disabled group and a normal group, performed a primary, reading-like, card-sorting task. After they completed the primary task, they were tested for memory of incidental materials presented during learning. While the normal children showed better recall of incidental materials related to the primary task, 24 children with disabilities showed superior recall of material irrelevant to the primary task. The results were discussed in terms of alternative "motivational" and "developmental lag" interpretations.     

III. WISC-R scatter indices: Useful information for differential diagnosis?

This study analyzed the WISC-R verbal-performance, full scale IQ, verbal IQ, and performance IQ scatter indices of 101 verified special education students. The results indicated that none of these measures discriminated among emotionally disturbed, learning disabled, minimally brain injured, and educable mentally retarded children. These scatter indices were also compared with analogous data collected from a nationwide, representative sample of normal children (Kaufman, 1976a, 1976b). Statistically significant differences were obtained between the two groups on verbal-performance, full scale IQ, and performance IQ scatter dimensions. Further analyses revealed, however, that 40% of the normal children exhibited as much or more scatter than the average special education student on each of these three scatter indices. There were no significant differences between the two groups on the verbal IQ scatter index. The results are discussed in terms of the limited utility of WISC-R scatter indices for the purpose of differential diagnosis.     

Event-related EEG oscillations to semantically unrelated words in normal and learning disabled children

Learning disabilities (LD) are one of the most frequent problems for elementary school-aged children. In this paper, event-related EEG oscillations to semantically related and unrelated pairs of words were studied in a group of 18 children with LD not otherwise specified (LD-NOS) and in 16 children with normal academic achievement. We propose that EEG oscillations may be different in LD NOS children versus normal control children that may explain some of the deficits observed in the LD-NOS group. The EEGs were recorded using the 10/20 system. EEG segments were edited by visual inspection 1000ms before and after the stimulus, and only correct responses were considered in the analysis. Time-frequency (1-50Hz) topographic maps were obtained for the increases and decreases of power after the event with respect to the pre-stimulus average values. Significant differences between groups were observed in the behavioral responses. LD-NOS children show less number of correct responses and more omissions and false alarms than the control group. The event-induced EEG responses showed significant differences between groups. The control group showed greater power increases in the frequencies 1-6Hz than the LD-NOS group from 300 to 700ms. These differences were mainly observed in frontal regions, both to related and non-related words. This was interpreted as a deficit in attention, both to internal and external events, deficits in activation of working memory and deficits in encoding and memory retrieval in the LD-NOS children. Differences between groups were also observed in the suppression of alpha and beta rhythms in the occipital regions to related words in frequencies between 8 and 17Hz from 450 to 750ms. LD-NOS children showed shorter durations of the decreases in power than the control group. These results suggest also deficits in attention and memory retrieval. It may be concluded that LD-NOS children showed physiological differences from normal children that may explain their cognitive deficiencies.     

Use of the dichotic listening technique with learning disabilities

Dichotic listening (DL) techniques have been used extensively as a non-invasive procedure to assess language lateralization among children with and without learning disabilities (LD), and with individuals who have other auditory system related brain disorders. Results of studies using DL have indicated that language is lateralized in children with LD and that the lateralized language asymmetries do not develop after age 6 nor are they affected by gender. Observed differences in lateralized language processes between control children and those with LD were found not due to delayed cerebral dominance, but rather to deficits in selective attention. In addition, attention factors have a greater influence on auditory processing of verbal than nonverbal stimuli for children with LD, and children with LD exhibit a general processing bias to the same hemisphere unlike control children. Furthermore, employing directed attention conditions in DL experiments has played an important role in explaining learning disabled children's performance on DL tasks. We conclude that auditory perceptual asymmetries as assessed by DL with children who experience LD are the result of the interaction of hemispheric capability and attention factors.     

WORD RECOGNITION SKILLS OF LEARNING DISABLED CHILDREN AND AVERAGE STUDENTS’

Abstract

The ability of learning disabled and average students’ to recognize and identify words was investigated. Two informal reading measures, the Sundbye Minimal Contrast Phonics Test and an oral reading sample, were administered to three groups. The groups were composed of learning disabled students evidencing reading problems (LD), average students matched with the learning disabled group on reading level and IQ (YN), and average students matched with the learning disabled group on chronological age and IQ (ON). The LD group and average readers did not differ on identification of symbol‐sound associations, word recognition proficiency, the ability to detect and correct word recognition errors, and the ability to use information within the text to recognize words. However, the LD and ON group differed on mean number of word recognition errors. Educational implications of the findings were discussed and a profile of the word recognition skills of learning disabled children was presented.     

Application of the verbal transformation effect with learning-disabled children

Verbal Transformations (VTs) are an illusory effect which results from hearing a tape recording consisting of one word repeated twice per second. VTs have been employed to ascertain auditory perceptual differences in normal subjects relative to chronological age. This research tested two groups of 10 male children (normal and learning disabled). Results showed a significant difference (p < .01) between the reported number of VTs per group, with normal subjects verbalizing more different words. LD results are compared to VT studies with geriatrics. A theory is presented to explain our findings based upon a defect in short-term memory.     

Numerical and arithmetical cognition: patterns of functions and deficits in children at risk for a mathematical disability.

Based on performance on standard achievement tests, first-grade children (mean age = 82 months) with IQ scores in the low-average to high-average range were classified as at risk for a learning disability (LD) in mathematics, reading, or both. These at-risk children (n = 55) and a control group of academically normal peers (n = 35) were administered experimental tasks that assessed number comprehension and production skills, counting knowledge, arithmetic skills, working memory, and ease of retrieving information from long-term memory. Different patterns of intact cognitive functions and deficits were found for children in the different at-risk groups. As a set, performance on the experimental tasks accounted for roughly 50% and 10% of the group differences in mathematics and reading achievement, respectively, above and beyond the influence of IQ. Performance on the experimental tasks thus provides insights into the cognitive deficits underlying different forms of LD, as well as into the sources of individual differences in academic achievement.     

Do semantic memory deficiencies underlie learning disabled readers' encoding processes?

This study investigates the extent to which learning disabled readers' atypical encoding relates to their deficiencies in semantic memory. Inferences related to ability group performance were based on the assumption that encoding involves the matching of incoming information against a featural representation of that information in semantic memory. To this end, learning disabled and nondisabled readers in two age groups were compared on dichotic listening recall tasks that included orienting and nonorienting instructions. Orienting instructions directed children's attention toward semantic, phonemic, or structural word features. Dependent measures were lateralization, free recall, retrieval organization, and selective attention. The efficiency of allocating attentional resources was inferred from correlations between central and incidental recall. Primary results included the following: Disabled and nondisabled readers' ear asymmetry differences were dependent upon age, orienting instructions, and type of word list; disabled readers' recall and organization scores were lower than skilled readers'; however, both ability groups benefitted from orienting instructions compared to nonorienting instructions; during orienting instructions, disabled readers were less able than skilled readers to divide their attention between target and nontarget word features, especially during interhemispheric processing conditions; and the relative efficiency of allocating attentional resources differed qualitatively between the two ability groups. The results suggest that ability group variations reflect the structure of the memory trace in interaction with ear presentation and encoding processes. It is inferred that disabled readers' inferior memory traces reflect the quantity and internal coherence of information stored in semantic memory as well as the means by which such information is accessed.     

Language skills in developmentally disabled children

Language measures of receptive and expressive vocabulary, story telling, and immediate verbal memory, as well as two perceptual tests, were administered to a group of developmentally disabled children, and three groups of normal children, one matched for chronological age, one for mean length of utterance, and one for performance on one of the perceptual tests. When diagnostic subgroups of “autism,” “childhood schizophrenia,” and “other severe disturbance” were formed using standard diagnostic tools, no language differences were found between diagnostic subgroups. When compared with the normal control groups, many of the language skills of the entire group of disabled children, and of the autistic children alone, were rather evenly delayed, showing only a relative sparing of the naming function, and a relative deficit on immediate verbal memory. Furthermore, a high correlation was found in a small subsample between the difficulty levels of morphemes in the disabled children and those reported for young normal children. Experienced special-education and early-childhood teachers could not discriminate the stories of the disabled children from those of young normal children. Analysis of the disabled children's error strategies, however, revealed features of their language not found in normal children's language: (1) extreme perseveration in test answers and stories, (2) attention to minor features of test stimuli, and (3) failure to adopt alternate, flexible communicative strategies. We conclude that the language acquisition of the developmentally disabled children is delayed but not deviant in its semantic and syntactic competence, and that current diagnostic practice does not differentiate linguistically distinct subgroups. We further argue that where developmentally disabled children do exhibit aberrant features of language, such deviance parallels similar features in other cognitive skills, and is not unique to language.     

Abstract categorization ability as a predictor of learning disability classification

Based on a theoretical analysis of the type of cognitive processing that should be sensitive to population differences, this study evaluated the diagnostic validity of a task measuring abstract categorization ability in six-, seven-, and eight-year-old learning disabled (LD) and non-LD peers. This research is part of a project, the major goal of which is the development of a cognitive-based preschool screening test for the early detection of children who may subsequently fail in school. Diagnostic validity is being evaluated within the context of the research strategy we have adopted. Data are presented that demonstrate that the component of abstract category knowledge that best discriminates LD children from non-LD peers, is knowledge of how members of abstract categories differ from each other. This is consistent with a priori predictions from theory.     

Attentional deficits in head-injured children: An information processing analysis

Attentional problems of closed head-injured (CHI) children were examined using an information processing (IP) approach. Based on Sternberg's (1969) additive factor method (AFM), the study examined attentional processes in terms of four stages and their corresponding task variables. A visual-spatial choice reaction-time task was undertaken with two groups of CHI children (severe and mild to moderate) and corresponding matched control groups. Results indicated that for this task both the CHI and the normal children exhibited a similar mode of linear, sequential information processing. It was found that the severe group was impaired not only in terms of slowed motor execution but also in terms of response selection. This group showed no impairment on the feature extraction, stimulus identification, and motor adjustment stages of processing. No evidence of impairment on any of the stages was found for the mild group. The utility of the AFM and implications of these findings are discussed with reference to CHI children and to neuropsychological assessment and rehabilitation.     

Differential constraints on the working memory and reading abilities of individuals with learning difficulties and typically developing children

This study examined the factors that constrain the working memory span performance and reading ability of individuals with generalized learning difficulties. In the study, 50 individuals with learning difficulties (LD) and 50 typically developing children (TD) matched for reading age completed two working memory span tasks. Participants also completed independent measures of the processing and storage operations involved in each working memory span task and Raven's Coloured Progressive Matrices. The results showed that despite an equivalent level of working memory span, the relative importance of the constraints on working memory differed between the groups. In addition, working memory span was not closely related to word recognition or sentence comprehension performance in the LD group. These results suggest that the working memory span performance of LD and TD individuals may reflect different working memory limitations and that individuals with generalized learning difficulties may approach cognitive tasks in a qualitatively different way from that of typically developing individuals.     

Children's metacognition: Exploring relations among knowledge,process, and motivational variables

Following a metamemory pretest, 60 first and third grade children (6 and 8 years of age, respectively) were divided into three treatment groups which received task-specific strategy instructions appropriate for three memory problems, general metacognitive information about subordinate and superordinate processing, or both strategy and metacognitive training. Maintenance and generalization versions of the memory tasks were given, followed by an attributional assessment of children's perceptions of the causes for specific success and failure outcomes. Post-training scores on the memory tasks showed that strategy training was highly successful. Metacognitive training appeared to have no effect on the metameory or strategy scores with one exception: metamemory and strategy use on the generalization task were significantly correlated only for children who received both metacognitive and strategy training. Apparently, children who were initially high in metamemory skills profited more from the comprehensive training package, using new metacognitive insights to aid the generalization of acquired strategies to the transfer tasks. Among strategy-trained children those who attributed success to effort were both more strategic and higher in metamemory than those who attributed task outcomes to noncontrollable factors such as ability or task characteristics. Results were discussed in terms of the interactive nature of knowledge, process, and motivational variables as determinants of strategy transfer.