Atypical predictive processing during visual statistical learning in children with developmental dyslexia: an event-related potential study

Previous research suggests that individuals with developmental dyslexia perform below typical readers on non-linguistic cognitive tasks involving the learning and encoding of statistical-sequential patterns. However, the neural mechanisms underlying such a deficit have not been well examined. The aim of the present study was to investigate the event-related potential (ERP) correlates of sequence processing in a sample of children diagnosed with dyslexia using a non-linguistic visual statistical learning paradigm. Whereas the response time data suggested that both typical and atypical readers learned the statistical patterns embedded in the task, the ERP data suggested otherwise. Specifically, ERPs of the typically developing children (n?=?12) showed a P300-like response indicative of learning, whereas the children diagnosed with a reading disorder (n?=?8) showed no such ERP effects. These results may be due to intact implicit motor learning in the children with dyslexia but delayed attention-dependent predictive processing. These findings are consistent with other evidence suggesting that differences in statistical learning ability might underlie some of the reading deficits observed in developmental dyslexia.     

Performance of children with developmental dyslexia on high and low topological entropy artificial grammar learning task

Graph complexity as measured by topological entropy has been previously shown to affect performance on artificial grammar learning tasks among typically developing children. The aim of this study was to examine the effect of graph complexity on implicit sequential learning among children with developmental dyslexia. Our goal was to determine whether children’s performance depends on the complexity level of the grammar system learned. We conducted two artificial grammar learning experiments that compared performance of children with developmental dyslexia with that of age- and reading level-matched controls. Experiment 1 was a high topological entropy artificial grammar learning task that aimed to establish implicit learning phenomena in children with developmental dyslexia using previously published experimental conditions. Experiment 2 is a lower topological entropy variant of that task. Results indicated that given a high topological entropy grammar system, children with developmental dyslexia who were similar to the reading age-matched control group had substantial difficulty in performing the task as compared to typically developing children, who exhibited intact implicit learning of the grammar. On the other hand, when tested on a lower topological entropy grammar system, all groups performed above chance level, indicating that children with developmental dyslexia were able to identify rules from a given grammar system. The results reinforced the significance of graph complexity when experimenting with artificial grammar learning tasks, particularly with dyslexic participants.     

Prevalence,gender ratio and gender differences in reading‐related cognitive abilities among Chinese children with dyslexia in Hong Kong

Based on the data of the normative study of the Hong Kong test of specific learning difficulties in reading and writing, and the Test of visual‐perceptual skills (non‐motor)—Revised, 99 children aged between 6 and 10½ years were identified as children with dyslexia out of the normative sample of 690 children. By excluding 12 children known to score below average in IQ, 87 children, including 20 children not tested for IQ, could be regarded as children with dyslexia, yielding a prevalence rate of 12.6% and a boy:girl gender ratio of 1.6 to 1. The figures would become 9.7% and 2.0 to 1 if the 20 children were omitted from computation. However, gender imbalance could not be readily explained by gender differences in reading‐related cognitive abilities, as there were only minor and subtle differences. Regression analyses to evaluate the relative contribution of different cognitive abilities to reading and writing suggested that orthographic knowledge and naming speed were most important among children with dyslexia. Implications of the findings and the need for early intervention are discussed.     

Screening for Chinese Children with Dyslexia in Hong Kong: The use of the Teachers' Behaviour Checklist

Primary school teachers rated the frequency of occurrence of 65 reading‐related behavioural characteristics in a sample of 251 Grade 1 to Grade 6 Chinese school children in Hong Kong. These behavioural characteristics were in the areas of general performance, reading, dictation, writing, mathematics, language, memory, concentration, sequential ability, motor co‐ordination, spatial orientation, and social/emotional adjustment. Of these 12 areas, 10 yielded scale scores that could distinguish children with dyslexia from those without dyslexia, identified on the basis of their performance in five domains of literacy and cognitive skills. Using a summary score derived from the 10 relevant scales, an optimal cut‐off score was suggested to arrive at a balance between high sensitivity and an acceptable rate of false positives in screening for children with dyslexia. The need for cross‐replication in screening children with dyslexia using the behaviour checklist with different samples of school students is emphasised.     

Implicit sequence learning is preserved in dyslexic children

This study investigates the implicit sequence learning abilities of dyslexic children using an artificial grammar learning task with an extended exposure period. Twenty children with developmental dyslexia participated in the study and were matched with two control groups—one matched for age and other for reading skills. During 3 days, all participants performed an acquisition task, where they were exposed to colored geometrical forms sequences with an underlying grammatical structure. On the last day, after the acquisition task, participants were tested in a grammaticality classification task. Implicit sequence learning was present in dyslexic children, as well as in both control groups, and no differences between groups were observed. These results suggest that implicit learning deficits per se cannot explain the characteristic reading difficulties of the dyslexics.     

Hearing Matters More Than Seeing: A Cross-Modality Study of Statistical Learning and Reading Ability

ABSTRACT

There is growing interest in the link between implicit statistical learning (SL) and reading ability. Although learning to read involves both auditory and visual modalities, it is not known whether reading skills might be more strongly associated with auditory SL or visual SL. Here we assessed SL across both modalities in 36 typically developing children and 36 healthy adults using the classic triplet-learning paradigm. Auditory SL was significantly associated with sentence reading fluency (Woodcock Johnson III Test of Achievement) in the combined sample of children and adults after controlling for age and nonverbal intelligence. In further analysis of the child data, auditory SL was significantly associated with nonword reading accuracy (Woodcock Reading Mastery Test), a relationship which appeared to be mediated by phonological processing abilities (Comprehensive Test of Phonological Processing). These findings suggest that auditory SL might contribute more strongly to certain aspects of reading development compared to visual SL.     

Dyslexie font does not benefit reading in children with or without dyslexia

In two experiments, the claim was tested that the font “Dyslexie”, specifically designed for people with dyslexia, eases reading performance of children with (and without) dyslexia. Three questions were investigated. (1) Does the Dyslexie font lead to faster and/or more accurate reading? (2) Do children have a preference for the Dyslexie font? And, (3) is font preference related to reading performance? In Experiment 1, children with dyslexia (n?=?170) did not read text written in Dyslexie font faster or more accurately than in Arial font. The majority preferred reading in Arial and preference was not related to reading performance. In Experiment 2, children with (n?=?102) and without dyslexia (n?=?45) read word lists in three different font types (Dyslexie, Arial, Times New Roman). Words written in Dyslexie font were not read faster or more accurately. Moreover, participants showed a preference for the fonts Arial and Times New Roman rather than Dyslexie, and again, preference was not related to reading performance. These experiments clearly justify the conclusion that the Dyslexie font neither benefits nor impedes the reading process of children with and without dyslexia.     

Dyslexic children show deficits in implicit sequence learning,but not in explicit sequence learning or contextual cueing

Dyslexia is a specific learning disability characterized by difficulties with accurate and/or fluent word recognition and by poor spelling abilities. The absence of other high level cognitive deficits in the dyslexic population has led some authors to propose that non-strategical processes like implicit learning could be impaired in this population. Most studies have addressed this issue by using sequence learning tasks, but so far the results have not been conclusive. We test this hypothesis by comparing the performance of dyslexic children and good readers in both implicit and explicit versions of the sequence learning task, as well as in another implicit learning task not involving sequential information. The results showed that dyslexic children failed to learn the sequence when they were not informed about its presence (implicit condition). In contrast, they learned without significant differences in relation to the good readers group when they were encouraged to discover the sequence and to use it in order to improve their performance (explicit condition). Moreover, we observed that this implicit learning deficit was not extended to other forms of non-sequential, implicit learning such as contextual cueing. In this case, both groups showed similar implicit learning about the information provided by the visual context. These results help to clarify previous contradictory data, and they are discussed in relation to how the implicit sequence learning deficit could contribute to the understanding of dyslexia.     

Project DyAdd: Implicit learning in adult dyslexia and ADHD

In this study of the project DyAdd, implicit learning was investigated through two paradigms in adults (18–55 years) with dyslexia (n?=?36) or with attention deficit/hyperactivity disorder (ADHD, n?=?22) and in controls (n?=?35). In the serial reaction time (SRT) task, there were no group differences in learning. However, those with ADHD exhibited faster RTs compared to other groups. In the artificial grammar learning (AGL) task, the groups did not differ from each other in their learning (i.e., grammaticality accuracy or similarity choices). Further, all three groups were sensitive to fragment overlap between learning and test-phase items (i.e., similarity choices were above chance). Grammaticality performance of control participants was above chance, but that of participants with dyslexia and participants with ADHD failed to differ from chance, indicating impaired grammaticality learning in these groups. While the main indices of AGL performance, grammaticality accuracy and similarity choices did not correlate with the neuropsychological variables that reflected dyslexia-related (phonological processing, reading, spelling, arithmetic) or ADHD-related characteristics (executive functions, attention), or intelligence, the explicit knowledge for the AGL grammar (i.e., ability to freely generate grammatical strings) correlated positively with the variables of phonological processing and reading. Further, SRT reaction times correlated positively with full scale intelligence quotient (FIQ). We conclude that, in AGL, learning difficulties of the underlying rule structure (as measured by grammaticality) are associated with dyslexia and ADHD. However, learning in AGL is not related to the defining neuropsychological features of dyslexia or ADHD. Instead, the resulting explicit knowledge relates to characteristics of dyslexia.     

Evaluating the teaching and learning experience for the child with dyslexia in special and mainstream settings in Ireland

This study examines and evaluates special provision for pupils with dyslexia in three different settings: reading schools, reading units and mainstream support. The research focused on the teaching and learning context for pupils with dyslexia, the support teacher, the mainstream teacher and the experience of the student. The main participants were teachers and tutors supporting pupils with dyslexia, and the parents of these children. Survey methods included questionnaires, focus group discussions, interviews and quantitative data on pupils' reading attainment. In addition, a total of six schools, two representing each model of support, were selected as case studies. This article reports part of a larger survey, which evaluated the effectiveness of three models of special provision for children with dyslexia in primary school. The study shows that there are academic and social benefits for the child with dyslexia who is enrolled in a special setting. However, placement in a reading school or reading unit per se does not guarantee that a child will ‘catch up’ with his or her peers. The findings reported a similarity in the methods and practices teachers use in both mainstream and special settings. The discussion suggests that if teachers are to ‘catch them before they fall’ there are serious questions that must be asked about how we are teaching basic literacy skills. The findings suggest an urgent need for a more balanced approach to teaching reading and writing.     

Reading comprehension,working memory and higher-level language skills in children with SLI and/or dyslexia

This study examined (1) whether working memory and higher-level languages skills—inferencing and comprehension monitoring—accounted for individual differences among Chinese children in Chinese reading comprehension, after controlling for age, Chinese word reading and oral language skills, and (2) whether children with specific language impairment (SLI) or dyslexia showed deficits in these skills. Eighty-two Cantonese Chinese-speaking children between the age of 7; 8–9; 5 were assessed. Regression analyses on the full sample offered support for the first question. The children were also classified into four groups: Typically-developing (TD; N = 34), specific language impairment-only (SLI-only; N = 18), SLI-dyslexia comorbid (SLI-D; N = 22) and dyslexia-only (D-only; N = 8). Pair-wise comparisons focusing on the second question revealed that both the SLI-only and the D-only group performed worse than the TD group in reading comprehension after controlling for age and nonverbal intelligence. The SLI-only and the D-only group showed a different profile of deficits: only the SLI-only group performed worse than the TD group in working memory, comprehension monitoring, and inferencing. The SLI-D comorbid group did worse than the SLI-only, but not the D-only group, in reading comprehension. The SLI-D comorbid group did not do worse than either single diagnosis group in the higher-level language skills associated with reading comprehension. These findings suggested adopting different intervention approaches for reading comprehension difficulties in children with SLI versus children with dyslexia.     

Comparison of deficits in cognitive and motor skills among children with dyslexia

There is a growing body of evidence that children with dyslexia have problems not just in reading but in a range of skills including several unrelated to reading. In an attempt to compare the severity and incidence of deficits across these varied domains, children with dyslexia (mean ages 8, 12, and 16 years), and control groups of normally achieving children matched for IQ and for age or reading age, were tested on a range of primitive (basic) skills. The children with dyslexia performed significantly worse than the same-age controls on most tasks, and significantly worse even than the reading-age controls on phoneme segmentation, picture naming speed, word tachistoscopic word recognition, speeded bead threading and some balance tasks. The overall performance of the children with dyslexia is interpreted as showing less complete automatization than normal.     

Are preservice teachers prepared to teach struggling readers?

Reading disabilities such as dyslexia, a specific learning disability that affects an individual’s ability to process written language, are estimated to affect 15–20% of the general population. Consequently, elementary school teachers encounter students who struggle with inaccurate or slow reading, poor spelling, poor writing, and other language processing difficulties. However, recent evidence may suggest that teacher preparation programs are not providing preservice teachers with information about basic language constructs and other components related to scientifically based reading instruction. As a consequence preservice teachers have not exhibited explicit knowledge of such concepts in previous studies. Few studies have sought to assess preservice teachers’ knowledge about dyslexia in conjunction with knowledge of basic language concepts. The purpose of the present study was to examine elementary school preservice teachers’ knowledge of basic language constructs and their perceptions and knowledge about dyslexia. Findings from the present study suggest that preservice teachers, on average, are able to display implicit skills related to certain basic language constructs (i.e., syllable counting), but fail to demonstrate explicit knowledge of others (i.e., phonics principles). Also, preservice teachers seem to hold the common misconception that dyslexia is a visual perception deficit rather than a problem with phonological processing. Implications for future research as well as teacher preparation are discussed.     

Computer-based learning of spelling skills in children with and without dyslexia

Our spelling training software recodes words into multisensory representations comprising visual and auditory codes. These codes represent information about letters and syllables of a word. An enhanced version, developed for this study, contains an additional phonological code and an improved word selection controller relying on a phoneme-based student model. We investigated the spelling behavior of children by means of learning curves based on log-file data of the previous and the enhanced software version. First, we compared the learning progress of children with dyslexia working either with the previous software (n = 28) or the adapted version (n = 37). Second, we investigated the spelling behavior of children with dyslexia (n = 37) and matched children without dyslexia (n = 25). To gain deeper insight into which factors are relevant for acquiring spelling skills, we analyzed the influence of cognitive abilities, such as attention functions and verbal memory skills, on the learning behavior. All investigations of the learning process are based on learning curve analyses of the collected log-file data. The results evidenced that those children with dyslexia benefit significantly from the additional phonological cue and the corresponding phoneme-based student model. Actually, children with dyslexia improve their spelling skills to the same extent as children without dyslexia and were able to memorize phoneme to grapheme correspondence when given the correct support and adequate training. In addition, children with low attention functions benefit from the structured learning environment. Generally, our data showed that memory sources are supportive cognitive functions for acquiring spelling skills and for using the information cues of a multi-modal learning environment.     

Developmental Outcomes for Children at High Risk of Dyslexia and Children With Developmental Language Disorder

We followed children at family risk of dyslexia and children with preschool language difficulties from age 3½, comparing them with controls (N = 234). At age 8, children were classified as having dyslexia or Developmental Language Disorder (DLD) and compared at earlier time points with controls. Children with dyslexia have specific difficulties with phonology and emergent reading skills in the preschool period, whereas children with DLD, with or without dyslexia, show a wider range of impairments including significant problems with executive and motor tasks. For children with both dyslexia and DLD, difficulties with phonology are generally more severe than those observed in children with dyslexia or DLD alone. Findings confirm that poor phonology is the major cognitive risk factor for dyslexia.     

Preschool predictors of dyslexia status in Chinese first graders with high or low familial risk

The present 4-year longitudinal study examined preschool predictors of Grade 1 dyslexia status in a Chinese population in Hong Kong where children started learning to read at the age of three. Seventy-five and 39 Chinese children with high and low familial risk respectively were tested on Chinese word reading, oral language skills, morphological awareness, phonological skills, rapid naming, and print-related skills from age 4 to 6 and a standardized dyslexia test at age 7. Results showed that children of the high risk group performed significantly worse than the low risk group in Chinese literacy, phonological awareness, and orthographic skills at age 7. All the children with dyslexia had word reading difficulties in at least one preschool year. Results of the logistic regression showed that preschool verbal production, syllable deletion, and letter naming were the best predictors of dyslexia outcome at age 7. As in alphabetic languages, preschool oral language skills like verbal production, phonological skills, and print-related skills are the most significant predictors of children’s later reading difficulties.     

Orthographic processing efficiency in developmental dyslexia: an investigation of age and treatment factors at the sublexical level

Reading fluency beyond decoding is a limitation to many children with developmental reading disorders. In the interest of remediating dysfluency, contributing factors need to be explored and understood in a developmental framework. The focus of this study is orthographic processing in developmental dyslexia, and how it may contribute to reading fluency. We investigated orthographic processing speed and accuracy by children identified with dyslexia that were enrolled in an intensive, fluency-based intervention using a timed visual search task as a tool to measure orthographic recognition. Results indicate both age and treatment effects, and delineate a link between rapid letter naming and efficient orthographic recognition. Orthographic efficiency was related to reading speed for passages, but not spelling performance. The role of orthographic learning in reading fluency and remediation is discussed.     

Children With Dyslexia: Not Necessarily at Risk for Elevated Internalizing Symptoms

The risk for internalizing disorders in children with learning disabilities is frequently debated in the research community and empirical responses are equivocal. For educators and clinicians, the frequent assumption is that children with dyslexia also have at least subtle emotional problems. In this study, school-age children with reading problems and their siblings (N=79) were referred for neuropsychological evaluation. As part of the assessment process, parents, teachers, and the child were asked to rate the child’s level of internalizing symptoms on several behavior rating scales. Results from analyses of the data, using both discrepancy and reading cut scores for diagnosis of dyslexia, suggest that children with dyslexia are not at elevated risk for behaviors related to anxiety, depression, and somatization. Additionally, children at the lowest end of the reading distribution were no more likely to have significant internalizing symptoms than children with less impaired reading.     

Developmental dyslexia in an orthography of intermediate depth: the case of European Portuguese

Fifteen Portuguese children with dyslexia, aged 9–11 years, were compared with reading and chronological age controls with respect to five indicators related to the phonological deficit hypothesis: the effects of lexicality, regularity, and length, implicit and explicit phonological awareness, and rapid naming. The comparison between groups indicates that Portuguese children with dyslexia have a phonological impairment which is revealed by a developmental deficit in implicit phonological awareness and irregular word reading (where younger reading level controls performed better than dyslexics) and by a developmental delay in decoding ability and explicit phonological awareness (where dyslexics matched reading level controls). These results are discussed in relation to the idea that European Portuguese is written in an orthography of intermediate depth.