Reading Disability Children Research Articles

Reading Disability in Children: Exploring the N400 and its Associations with Set-For-Variability

ABSTRACT The N400 event-related potential (ERP), a marker of lexical-semantic processing, can assess the neural basis of reading difficulties. This study examines 1) semantic processes in typically developing (TD) children and children with reading disabilities (RD) using N400 and Set-for-Variability (SfV) profiles and 2) correlations between N400 and SfV. Fifty-one children read congruent and incongruent sentences during EEG. Results showed RD children lacked an N400 effect and had delayed SfV. A negative correlation between SfV and N400 latency in the RD group indicated distinct semantic processing delays in these children.

ELECTROOCULOGRAPHY BASED READING SPEED ANALYSIS AS AN ASSISTIVE TOOL

Dyslexia is a well-known reading disorder that involves difficulty in fluent reading, decoding and processing of words despite adequate intelligence. It is common that the reading speed of dyslexic patients is lower than their normal counterparts, because of slow letter and word processing. Eye movements in dyslexic patients are significantly different from that of normal individuals, in terms of the presence of frequent fixations and stares in the former. This work proposes a Human Computer Interactive system to assist individuals having low reading speed to increase their reading speed by the analysis of eye movements. Eye movement data for different reading speeds is recorded using a laboratory developed Electrooculogram acquisition system. From the data, Adaptive Autoregressive (AAR) parameters, Band Power Estimates and Wavelet Coefficients are extracted as signal features. Reading speeds are classified using different pattern classifiers from which an average accuracy of 94.67% over all classes and participants is obtained using Radial Basis Function (RBF) Support Vector Machine (SVM) Tree classifier and AAR Parameters as features. Friedman test is done to select the best classifier. The trained classifier is used to recognize the reading speeds of a set of new normal individuals. If the reading speeds are less than a preset threshold, that individual is trained repeatedly for 10 days for improvement. An improvement of reading speed is observed by the decrease in the misclassification rate from 45.1% to 9.92% in 10 days for the fastest speed (1 sentence/2 s) over all the subjects. This work is carried out on healthy individuals. However, the results reveal that the proposed system may also be used for training and assisting children with dyslexia or other similar reading disabilities children.

Memory and comprehension deficits in spatial descriptions of children with non-verbal and reading disabilities.

The present study investigated the difficulties encountered by children with non-verbal learning disability (NLD) and reading disability (RD) when processing spatial information derived from descriptions, based on the assumption that both groups should find it more difficult than matched controls, but for different reasons, i.e., due to a memory encoding difficulty in cases of RD and to spatial information comprehension problems in cases of NLD. Spatial descriptions from both survey and route perspectives were presented to 9–12-year-old children divided into three groups: NLD (N = 12); RD (N = 12), and typically developing controls (TD; N = 15); then participants completed a sentence verification task and a memory for locations task. The sentence verification task was presented in two conditions: in one the children could refer to the text while answering the questions (i.e., text present condition), and in the other the text was withdrawn (i.e., text absent condition). Results showed that the RD group benefited from the text present condition, but was impaired to the same extent as the NLD group in the text absent condition, suggesting that the NLD children’s difficulty is due mainly to their poor comprehension of spatial descriptions, while the RD children’s difficulty is due more to a memory encoding problem. These results are discussed in terms of their implications in the neuropsychological profiles of children with NLD or RD, and the processes involved in spatial descriptions.

Anxiety and Depression in Children With Nonverbal Learning Disabilities, Reading Disabilities, or Typical Development

The main goal of the present study was to shed further light on the psychological characteristics of children with different learning disability profiles aged between 8 and 11 years, attending from third to sixth grade. Specifically, children with nonverbal learning disabilities (NLD), reading disabilities (RD), or a typical development (TD) were tested. In all, 15 children with NLD, 15 with RD, and 15 with TD were administered self-report questionnaires to assess different types of anxiety and depression symptoms. Both NLD and RD children reported experiencing more generalized and social anxiety than TD, the NLD children reported more severe anxiety about school and separation than TD, and the children with RD had worse depressive symptoms than those with NLD or TD.

The Neural Correlates of Reading Fluency Deficits in Children

Multiple studies have shown that individuals with a reading disability (RD) demonstrate deficits in posterior left-hemispheric brain regions during reading-related tasks. These studies mainly focused on reading sub-skills, and it remains debated whether such dysfunction is apparent during more ecologically valid reading skills, such as reading fluency. In this fMRI study, reading fluency was systematically varied to characterize neural correlates of reading fluency in 30 children with (RD) and without (typical developing children, TYP) a RD. Sentences were presented at constrained, comfortable, and accelerated speeds, which were determined based on individual reading speed. Behaviorally, RD children displayed decreased performance in several reading-related tasks. Using fMRI, we demonstrated that both TYP and RD children display increased activation in several components of the reading network during fluent reading. When required to read at an accelerated speed, RD children exhibited less activation in the fusiform gyrus (FG) compared with the TYP children. A region of interest analysis substantiated differences in the FG and demonstrated a relationship to behavioral reading performance. These results suggest that the FG plays a key role in fluent reading and that it can be modulated by speed. These results and their implications for remediation strategies should be considered in educational practice.

Similar alterations in brain function for phonological and semantic processing to visual characters in Chinese dyslexia

Dyslexia in alphabetic languages has been extensively investigated and suggests a central deficit in orthography to phonology mapping in the left hemisphere. Compared to dyslexia in alphabetic languages, the central deficit for Chinese dyslexia is still unclear. Because of the logographic nature of Chinese characters, some have suggested that Chinese dyslexia should have larger deficits in the semantic system. To investigate this, Chinese children with reading disability (RD) were compared to typically developing (TD) children using functional magnetic resonance imaging (fMRI) on a rhyming judgment task and on a semantic association judgment task. RD children showed less activation for both tasks in right visual (BA18, 19) and left occipito-temporal cortex (BA 37), suggesting a deficit in visuo-orthographic processing. RD children also showed less activation for both tasks in left inferior frontal gyrus (BA44), which additionally showed significant correlations with activation of bilateral visuo-orthographic regions in the RD group, suggesting that the abnormalities in frontal cortex and in posterior visuo-orthographic regions may reflect a deficit in the connection between brain regions. Analyses failed to reveal larger differences between groups for the semantic compared to the rhyming task, suggesting that Chinese dyslexia is similarly impaired in the access to phonology and to semantics from the visual orthography.

Cognition and literacy in English language learners at risk for reading disabilities.

This study explores the cognitive basis of reading disabilities (RDs) in Spanish-speaking children who are learning English as a second language. Children (N = 393) designated as English language learners (ELLs) or bilingual with and without RDs in Grades 1, 2, and 3 were administered a battery of cognitive (short-term memory, working memory, rapid naming, random letter and number generation), vocabulary, and reading measures in both Spanish and English. Four important findings emerged. First, children at risk for RD and ELL children share common problems in English phonological processing and naming speed, as well as on language general measures of working memory and ratings of classroom attention. Second, children at risk for RD in both bilingual and ELL samples share similar cognitive difficulties, but Spanish phonological processing partials out performance differences between RD and non-RD groups only in the bilingual sample. Third, differences among RD subgroups were isolated to measures of classroom inattention, English naming speed, and phonological processing. Fourth, performance as a function of language status and RD was related to a language general working memory factor. In general, the results support the notion that Language 1 phonological processing as well as a general working memory system underlie second-language acquisition and RD in children whose first language is Spanish.

Children with reading disability show brain differences in effective connectivity for visual, but not auditory word comprehension.

BackgroundPrevious literature suggests that those with reading disability (RD) have more pronounced deficits during semantic processing in reading as compared to listening comprehension. This discrepancy has been supported by recent neuroimaging studies showing abnormal activity in RD during semantic processing in the visual but not in the auditory modality. Whether effective connectivity between brain regions in RD could also show this pattern of discrepancy has not been investigated.Methodology/Principal FindingsChildren (8- to 14-year-olds) were given a semantic task in the visual and auditory modality that required an association judgment as to whether two sequentially presented words were associated. Effective connectivity was investigated using Dynamic Causal Modeling (DCM) on functional magnetic resonance imaging (fMRI) data. Bayesian Model Selection (BMS) was used separately for each modality to find a winning family of DCM models separately for typically developing (TD) and RD children. BMS yielded the same winning family with modulatory effects on bottom-up connections from the input regions to middle temporal gyrus (MTG) and inferior frontal gyrus(IFG) with inconclusive evidence regarding top-down modulations. Bayesian Model Averaging (BMA) was thus conducted across models in this winning family and compared across groups. The bottom-up effect from the fusiform gyrus (FG) to MTG rather than the top-down effect from IFG to MTG was stronger in TD compared to RD for the visual modality. The stronger bottom-up influence in TD was only evident for related word pairs but not for unrelated pairs. No group differences were noted in the auditory modality.Conclusions/SignificanceThis study revealed a modality-specific deficit for children with RD in bottom-up effective connectivity from orthographic to semantic processing regions. There were no group differences in connectivity from frontal regions, suggesting that the core deficit in RD is not in top-down modulation.

The Influence of "Hot" Executive Function on the Verbal Working Memory of Attention Deficit Hyperactivity Disorder (ADHD) and Reading Disability (RD) Children

The deficit of "cool" executive function (EF) associated with dorsolateral prefrontal cortex (DLPFC) in attention deficit hyperactivity disorder (ADHD) has been substantially confirmed. But whether ADHD children show the deficit of "hot" EF associated with orbital and medial prefrontal cortex (OMPFC) remains unknown, and till now no research made an explicit exploration for interaction models between the two EFs. Commonly different from some studies related to the children’s gambling task, in which the "hot" EF impeded "cool" EF, this study aims to explore the facilitation of the "hot" EF to "cold" EF in the entertaining verbal N-back task. Pure cognitive processions were involved in boring N-back task while both "hot" EF and "cold" EF were involved in the entertaining N-back task. Participants were 77 children age between seven and twelve, of whom 60 were classified as having ADHD and /or reading disability (RD). All the disorder participants were recruited at a clinic and normal children were recruited from a elementary school. A four-group mixed design consisting of reading disabilities only (RD, n=15), reading disabilities and ADHD (RD+ADHD, n=24), ADHD only (ADHD, n=21) and a comparison group (n=17) was utilized. In the experiment, two adapted N-back working memory paradigms were used to explore verbal working memory ability, one was a traditional N-back task, another was entertaining N-back task. There are the same difficulty and materials between the two tasks. The results indicate that ADHD and RD groups behaved worse than comparison group and no significant differences had been detected between ADHD and RD groups in the boring task. A significant increase in ADHD had been found when comparing entertaining task with boring task. No significant differences had been detected between ADHD and comparison groups. Also, no significant changes related to the task types had been found in RD children. All these findings suggest that ADHD and RD children both show verbal working memory problems, however they have different mechanisms. The "hot" EF facilitates the performance of ADHD in verbal working memory task while not to RD. These results support the Haber model indirectly. According to this model, "hot" EF modulates "cool" EF by a special pathway.

Contrasting deficits on executive functions between ADHD and reading disabled children

The object of this study was to analyze the executive functioning of children with attention deficit hyperactivity disorder (ADHD) or reading disability (RD) independent of their non-executive deficits. Three carefully diagnosed groups of children, aged between 7 and 12 years (35 ADHD, 22 RD and 30 typically developing children), were tested on a wide range of tasks related to five major domains of executive functioning (EF): inhibition, visual working memory, planning, cognitive flexibility, and verbal fluency. Additional tasks were selected for each domain to control for non-executive processing. ADHD children were impaired on interference control, but not on prepotent and ongoing response suppression. ADHD showed deficits on visual working memory, planning, cognitive flexibility and phonetic fluency. RD children were impaired on phonetic fluency. The only EF measure that differentiated ADHD from RD was planning. The present sample of ADHD children showed several EF deficits, whereas RD children were almost spared executive dysfunction, but exhibited deficits in phonetic fluency.

Growth in literacy and cognition in bilingual children at risk or not at risk for reading disabilities.

This study investigated growth in reading, vocabulary, and memory in children (ages 5 to 10) learning English as a second language identified at risk for reading disabilities (RD). A growth curve analysis showed that RD children were significantly below children not at risk in English and Spanish reading, Spanish short-term memory (STM), Spanish comprehension, and English and Spanish working memory (WM). RD children were also inferior on growth measures of English and Spanish WM and Spanish STM. Growth on measures of Spanish vocabulary, reading, STM, and WM accounted for 12% of the variance in predicting growth in English reading. However, only Spanish measures of WM growth contributed unique variance. The results show that growth in WM in the primary language predicts growth in second-language reading.

Cognitive Processing of Low Achievers and Children with Reading Disabilities: A Selective Meta-Analytic Review of the Published Literature

This article synthesizes some of the published literature comparing the cognitive functioning of children with reading disabilities (RD) and children with low reading and low intelligence (low achievers). Nineteen studies, which yielded 274 effect sizes (ESs), indicated that children with reading disabilities outperformed low achievers (LA) on measures of lexical knowledge, syntactical knowledge, and visual-spatial processing (ES means =.55,.87,.36, respectively), but not on measures of phonological processing [e.g., ES mean =.25 for pseudo-word reading, ES mean = -.06 for automaticity (rapid naming)]. Regression modeling indicated that the magnitude of effect size differences on cognitive measures between RD and LA children was significantly related to chronological age (older participants yield smaller effect sizes than younger participants) and verbal IQ (the greater the difference in IQ between RD and LA participants the larger the effect size). Model testing further supported the hypothesis that relative to other cognitive measures, children with RD share a common phonological core deficit with LA achievers. However, the results indicated that the deficits shared between these two groups are much broader than a phonological core. The results were discussed within the context of defining children with RD by discrepancy criteria and how advances in the classification of such children might occur.

Language abilities in children with attention deficit hyperactivity disorder, reading disabilities, and normal controls.

Research has demonstrated a high prevalence of language impairments (LI) and reading disabilities (RD) in children with attention deficit hyperactivity disorder (ADHD). Since RD is also associated with LI, it is unclear whether the language impairments are specific to ADHD or associated with comorbid RD. The language abilities of ADHD children with and without RD were investigated in a task requiring recall of a lengthy narrative, and in tests assessing knowledge of the semantic aspects of language. The study was conducted with 50 boys--14 ADHD, 14 ADHD + RD, 8 RD, and 14 normal controls, aged 7 to 11. Children with ADHD (ADHD-only, ADHD + RD) exhibited difficulties in organizing and monitoring their story retelling. Children with RD (RD-only, ADHD + RD) demonstrated deficits in receptive and expressive semantic language abilities on the language processing tests. The comorbid group (ADHD + RD) exhibited the deficits of both ADHD and RD children. The deficiencies of ADHD children are consistent with higher-order executive function deficits while the deficits of RD children are consistent with deficits in the basic semantics of language processing.

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.

Memory Abilities of Reading-Disabled Children with VIQ-PIQ Differences

Associations between VIQ and verbal memory and between PIQ and nonverbal memory have been found in neurologically impaired adults. This study examined the assumption that similar associations will hold for children with reading disabilities (RD) who demonstrate lower VIQ relative to PIQ and the converse. The Verbal and Nonverbal Selective Reminding Tests were administered to children aged 10 to 12 years. Thirteen RD children with VIQ < PIQ 14 RD children with PIQ < VIQ and 14 controls served as subjects. Contrary to predictions, memory functions were not found to parallel intellectual functions. The children with lower PIQ displayed poorer storage and retrieval of verbal information along with poorer retrieval of nonverbal information. These results suggest that children with reading disabilities who obtain relatively lower PIQ might be expected to experience more memory problems than children with lower VIQ regardless of modality of input.

II. Separate brain potential characteristics in children with reading disability and attention deficit disorder: Color and letter relevance effects

This experiment was on event-related potential (ERP) indicants of the selective neural processing of black vs. white and letter vs. nonletter stimuli in boys (8–12 years of age) with and without a reading disability (RD) and/or attentional deficit disorder (ADD). Selective neural processing was measured by the increase or difference in ERP amplitude in response to stimuli that were relevant as compared to irrelevant to the color or letter attention task. The 52 children that participated in the study constituted four groups: 25 normal reading children (17 without ADD and 8 with ADD), and 27 RD children (11 without ADD and 16 with ADD). ERPs were recorded over the left and right occipital, central, and frontal regions. Selective neural processing due to stimulus relevance was reduced in boys with RD as compared to normal readers. This reduced selectivity was indicated by a predominantly symmetrical reduction in the magnitude of a positive difference potential over the central regions, between 300 and 360 msec, and then by a left greater than right hemisphere reduction in the magnitude of a positive difference potential over the occipital regions, at about 400 msec. Task relevance increased the within-subject and condition variability of this occipital positive component and this effect was greater for boys without than with RD, particularly over the left hemisphere. Selective neural processing due to stimulus relevance was greater in boys with ADD as compared to those without ADD. This was indicated by an increase in the magnitude of a positive difference potential between 320 and 400 msec over the central and frontal regions and a slow, late, negative difference potential between 600 and 800 msec over the central and occipital regions. These ADD effects tended to be greater over the right than left hemisphere. The unique polarity, scalp distribution, and time course of the effects of RD as compared to ADD on ERPs to relevant stimuli clearly indicated these two disorders, in part, involve different underlying brain deficits.

Developmental trends within memory‐deficient reading‐disability subtypes

This study examined memory patterns of children from three memory‐deficient reading‐disability (RD) groups that differed according to patterns of abstract reasoning and perceptuomotor functions. The investigation examined differences on a verbal learning task among four different age groups and among different neuropsychological subtypes. Results suggested that performances of the subtypes varied across trials and that each group benefited from repeated trials of the task. Developmental trends were also noted. Findings suggest that some RD children may not consistently utilize verbal strategies for coding/retrieval of information. Furthermore, remedial interventions need to consider both developmental and neuropsychological factors.

Bisensory memory in normal and reading disability children

Normal and reading disability children were tested for memory of item and order information in a sequential memory task with auditory and visual stimuli. There were three auditory visual digit pairs on each trial, with a 1-sec delay between successive pairs. Either one auditory-visual pair (pair condition) or two digits from one modality (modality condition) were tested. More errors were made in the pair than in the modality condition on a measure of item information but not on a measure of order information. Reading disability children made more errors than normal children, but there were no Reading Group by Condition interactions. These results suggest that: (a) the reading groups differed on general information-processing capabilities, but (b) both reading groups have the same degree of difficulty with organization of temporal-modality information.

Learning problems: Clinical findings in reading disability children–special cases of intellectual inhibition.

Learning problems: Clinical findings in reading disability children–special cases of intellectual inhibition.