Dyslexic Group Research Articles

CFD-14: detecting literacy and dyslexia risks in early and primary education

This study validates the CFD-14 questionnaire, designed for families to detect early risk of literacy difficulties and dyslexia in compulsory schooling. The sample included families of 1385 students from preschool (5 years old) and 1st to 6th grade of primary education, with a median age of 9 years and two months. The CFD-14 comprises 14 items reflecting common dyslexia indicators. Its one-dimensional factorial structure was confirmed, demonstrating reliability and criterion validity through five evidences: correlation of questionnaire scores with teacher and family assessments, comparison of CFD-14 scores between a dyslexic group (n = 13) and the general sample, analysis between families with and without a history of difficulties, and comparison between groups with persistent spelling errors and those without. A direct score at the 90th percentile was identified as the objective criterion to pinpoint students at risk of literacy difficulties.

Brain Laterality in Dyslexia Seen during Literacy Development and Early Training.

During the period in which children learn to read and write, a gradual shift from right to left hemisphere dominance for language is typically seen. However, in children with dyslexia, a deviant pattern is described in the literature. As part of a larger longitudinal study (The Bergen Longitudinal Dyslexia Study), the present study aimed to assess this development from an early age before children learn to read and write. Dichotic listening (DL), which is a non-invasive test, was used to assess the development of brain laterality in a Typical group and a Dyslexia group. The participants received yearly sessions of evidence-based literacy training at ages 5 to 7. The Typical group showed increasing ear scores and a shift from no ear advantage in the Pre-literacy stage (age 6), indicative of no hemisphere dominance, to a right ear advantage, indicative of a left hemisphere dominance, in the Emergent literacy stage (age 8) and the Literacy stage (age 11). The Dyslexia group showed a different pattern, with a significant right ear advantage at age 6, indicative of a right hemisphere dominance, and increasing ear scores at ages 8 and 11; however, no ear dominance was observed in the Literacy stage. The results point to an effect of relevant, evidence-based training affecting both right and left hemispheres in dyslexia, which should form a basis for further research.

Data-driven exploratory method investigation on the effect of dyslexia education at brain connectivity in Turkish children: a preliminary study

Dyslexia is a specific learning disability that is neurobiological in origin and is characterized by reading and/or spelling problems affecting the development of language-related skills. The aim of this study is to reveal functional markers based on dyslexia by examining the functions of brain regions in resting state and reading tasks and to analyze the effects of special education given during the treatment process of dyslexia. A total of 43 children, aged between 7 and 12, whose native language was Turkish, participated in the study in three groups including those diagnosed with dyslexia for the first time, those receiving special education for dyslexia, and healthy children. Independent component analysis method was employed to analyze functional connectivity variations among three groups both at rest and during the continuous reading task. A whole-brain scanning during task fulfillment and resting states revealed that there were significant differences in the regions including lateral visual, default mode, left frontoparietal, ventral attention, orbitofrontal and lateral motor network. Our results revealed the necessity of adding motor coordination exercises to the training of dyslexic participants and showed that training led to functional connectivity in some brain regions similar to the healthy group. Additionally, our findings confirmed that impulsivity is associated with motor coordination and visuality, and that the dyslexic group has weaknesses in brain connectivity related to these conditions. According to our preliminary results, the differences obtained between children with dyslexia, group of dyslexia with special education and healthy children has revealed the effect of education on brain functions as well as enabling a comprehensive examination of dyslexia.

Number sense deficits in children with developmental dyscalculia, dyslexia, co-occurring disorder and their typically developing peers

The aim of this study was to explore a number sense deficits in children with developmental dyscalculia, dyslexia, co-occurring disorder and their typically developing peers. A non-symbolic quantity comparison task was used in this study to examine whether children with dyscalculia have number sense deficits. Children aged 10–11 years old from nine primary schools in Taif city, Saudi Arabia, were selected to participate in this study. The children were divided into the dyscalculia group (n = 62), the dyslexia group (n = 60), and co-occurring disorder group (n = 65), and the typically developing peers group (n = 100).4 groups (dyscalculia, dyslexia, co-occurring disorder and typically developing peers group) × 2 stimulus ratio (6:7; 8:12). There were significant differences in non-symbolic quantity comparison tasks between children with dyslexia, co-occurring disorder, and typically developing peers. These results indicate that children with dyscalculia do have number sense deficiencies, but number sense deficiencies are not specific to children with dyscalculia.

Analysis of reading-task-based brain connectivity in dyslexic children using EEG signals.

Developmental dyslexia, a neurodevelopment reading disorder, can impact even children with average intelligence. The present study examined the brain connectivity in dyslexic and control children during the reading task using graph theory. 19-channel electroencephalogram (EEG) signals were recorded from 15 dyslexic children and 15 control children. Functional connectivity was estimated by measuring the EEG coherence at 19 electrode locations, and graph measures were calculated using the graph theory method. Reading task results identified deprived task performance in dyslexic children against controls. Graph measures revealed longer path length, reduced clustering coefficient and reduced network efficiencies (in theta and alpha bands) of dyslexic group. At the nodal level, we found a significant increase in delta strength (T4 and T5 electrode locations) and reduced strength in theta (T6, P4, Fp1, F8 and F3) and alpha bands (T4, T3, P4 and F3) during the reading task in dyslexic group. In conclusion, the present study identified distinct graph measures between groups when performing a reading task and showed possible evidence for compromised brain networks in dyslexic group.

Evaluation of the multiple-deficit hypothesis among dyslexic Arabic-speaking children.

This study examined the multiple-deficit hypothesis among Arabic-speaking elementary school students. A total of 90 students, divided into three main groups based on their performance on an Arabic word-reading task: dyslexic (n = 30), regular age-matched (n = 30), and 3rd-grade regular students, who were matched to the dyslexic group in regard to their reading proficiency level (n = 30). Participants underwent a nine-domain Arabic reading experiment that measured accuracy and fluency to evaluate general reading proficiency. The performance of Arabic dyslexic students was significantly worse than age-matched controls, but similar to young matched controls based on the reading level of each cognitive task. Moreover, dyslexic students showed deficits in three or more cognitive functions, depending on severity. This study adds to the limited empirical research on the double-deficit hypothesis and its extension to the multiple-domain model among young Arabic students.

Exploring the Impact of Matching E-Training Material to Arabic Dyslexia Type on Learners’ Reading Performance, Satisfaction and Behaviour

Abstract Dyslexia is a reading difficulty that can be found everywhere, regardless of a person’s ethnicity or race. The manifestation of dyslexia depends on the structure and orthography of a language. There is a lack of research into Arabic dyslexia, particularly the benefits of adaptive learning in this area. The study presented in this paper aimed to understand the impact on learners’ reading performance, satisfaction and behaviour when matching e-training material with learner attributes. The focus is on learners with short vowel dyslexia. The study was undertaken with 22 female primary school children in Saudi Arabia, all of whom were native Arabic speakers. These children were divided into two groups: a matched group (which included learners with short vowel dyslexia) and a mismatched group (which included learners with vowel dyslexia). An e-training system ‘DysTypeTrain2’ was designed and developed to support the study. A mixed-methods approach was used to collect both quantitative and qualitative data. The quantitative data were collected from (i) pre- and post-test results to calculate the improvement in reading performance and (ii) learner satisfaction scores. The qualitative data were collected from observations of learners’ behaviour. It was found that the learners’ reading performance and satisfaction improved in both experimental conditions (short vowel dyslexia group and vowel dyslexia group), regardless of their Arabic dyslexia type, indicating that the system was effective and the learning process was improved. Further, the learners were happy and excited about the system.

People with dyslexia or dyscalculia are less biased: Results of a preregistered study from over 450,000 people on the implicit association test

The implicit association test (IAT) provides a sensitive measure of attitudes to social dimensions such as race, gender or disability using a response speed procedure. The automatisation deficit account of dyslexia attributes the reading (and broader) difficulties of dyslexic people to reduced speed and strength of stimulus–response habit formation and, therefore, predicts reduced implicit bias for individuals with dyslexia. This novel prediction was tested using the ‘Project Implicit’ IAT database on attitudes to disability. Data from over 460,000 respondents was analysed, including 22,747 with physical disability (PD), 14,700 with dyslexia, and 1721 with dyscalculia. The dyslexia group did indeed show significantly less ‘Disability Bias’ than both the PD and no disability groups. Intriguingly, the dyscalculia group showed significantly less disability bias even than the dyslexia group. The results are interpreted within the learning framework of broader automatisation deficit and have ramifications for understanding both conditions and the processes of development of implicit bias in neurodiverse and neurotypical populations.

Evaluating the macular vascular complexes' density by OCTA for dyslexia

Aims/Purpose: To compare the vascular density of macular superficial and deep vascular complexes between dyslexic subjects and normoreaders at the fovea and parafovea.Methods: We performed a pilot study examining 60 eyes—36 of subjects with dyslexia and 24 of normoreaders as controls. Al the participants underwent an ophthalmological examination complemented with an optical coherence tomography angiography (OCTA) (Spectralis, Heidelberg Engineering, Germany), in which we measured the vascular density of the deep and superficial vascular complexes of the macula using an ETDRS123 pattern.Results: The deep vascular complex of the fovea was found to have a significant increase in the density of the different subfields of the inner and outer parafovea in the dyslexic group, as compared to the normoreaders. In contrast, no differences were found for the superficial vascular complex at any subfield.Conclusions: The increase in the deep vascular complex density of the macula could be associated with dyslexia.

Response to intervention as an identification strategy of the risk for dyslexia.

To develop on intervention process to identify children at risk of dyslexia, based on the Response to Intervention model. Specifically, to identify the pattern of changes in post-intervention performance in tasks of phonological awareness, working memory, lexical access, reading and writing; and to analyze which cognitive functions had a significant effect on the discriminating students at risk of dyslexia. Sample of 30 participants with Reading and writing difficulties, aged 8-11, from public/private schools, students from 3rd to 5th grade. Participants were submitted to a battery of cognitive-linguistic tests, before and after 12 intervention sessions. To monitor their performance, five reading and writing lists of words and pseudowords were applied. We qualitatively and quantitatively analyzed the differences in pre- and post-intervention performance of each participant; and among participants in the post-assessment, to understand the patterns of dyslexia vs non-dyslexia groups. There were statistically significant changes in: rapid automatized naming, narrative text comprehension, phonological awareness, rate and typology of hits/misses in reading and writing, and reading speed. Being the last three variables the most sensitive to discriminate the two groups, all with less post-intervention gains for the dyslexia group. The intervention focused on the stimulation of phonological skills and explicit and systematic teaching of graphophonemic correspondences contributed positively to the evolution of the group's participants. The intervention response approach favored the identification of children with a profile at risk for dyslexia, as distinct from children with other learning difficulties.

Resposta à intervenção como estratégia de identificação do risco para dislexia

ABSTRACT Purpose To develop on intervention process to identify children at risk of dyslexia, based on the Response to Intervention model. Specifically, to identify the pattern of changes in post-intervention performance in tasks of phonological awareness, working memory, lexical access, reading and writing; and to analyze which cognitive functions had a significant effect on the discriminating students at risk of dyslexia. Method Sample of 30 participants with Reading and writing difficulties, aged 8-11, from public/private schools, students from 3rd to 5th grade. Participants were submitted to a battery of cognitive-linguistic tests, before and after 12 intervention sessions. To monitor their performance, five reading and writing lists of words and pseudowords were applied. We qualitatively and quantitatively analyzed the differences in pre- and post-intervention performance of each participant; and among participants in the post-assessment, to understand the patterns of dyslexia vs non-dyslexia groups. Results There were statistically significant changes in: rapid automatized naming, narrative text comprehension, phonological awareness, rate and typology of hits/misses in reading and writing, and reading speed. Being the last three variables the most sensitive to discriminate the two groups, all with less post-intervention gains for the dyslexia group. Conclusions The intervention focused on the stimulation of phonological skills and explicit and systematic teaching of graphophonemic correspondences contributed positively to the evolution of the group's participants. The intervention response approach favored the identification of children with a profile at risk for dyslexia, as distinct from children with other learning difficulties.

Rhythm and Reading Abilities

This study was conducted to investigate the previously indicated causal relationship between reading impairment and difficulties in rhythm perception in an adult sample. In our study the comparison was made between the family risk for dyslexia and the no-risk for dyslexia groups to assess the possibility of shared risk factors. We hypothesized that a relationship exists between reading deficits and lower performance in rhythm perception within the family risk for dyslexia participant group. The participants were young adults (N = 119, aged from 20 to 48 years old). We assessed the reading abilities, rhythm perception performance and memory performance, and sensorimotor music reward experiences of our participants. Our results indicate that in adulthood rhythm perception appears to correlate with aspects of memory function, rather than with measures of reading fluency. Our results also suggest an indirect relationship between rhythm perception and word text reading fluency through short-term memory within the family risk for dyslexia group. A weak positive correlation between sensorimotor musical reward experience and pseudoword reading fluency was detected as well. We suggest family risk for dyslexia as an additional variable in future research.

Probing the phonological-coding deficit in dyslexia with vowel length perception

There is an established linkage between dyslexia and anomalous processing of speech sounds. We probed this in a Danish language context with vowel length tasks based on “kugle” ball /ku:lə/ and sequential deletions of the vowel portion to yield “kulde” coldness /kulə/. Vowel length continua are methodologically advantageous as they do not involve the perception of a sudden phonetic change that may instead tap other auditory processing abilities. Identification and discrimination tasks were administered to tertiary (n = 28), reading impaired (n = 26), and lower secondary students (n = 20), and the latter were approximately aged matched to the reading-impaired group. Identification functions derived from regression modelling of the responses showed that the dyslexics had significantly flatter curves than the other groups. Moreover, the secondary and dyslexic groups differed at the long vowel extremity of the continuum. Discrimination results showed that mean peak sensitivity of the tertiary students was higher than that of the secondary and dyslexic students. These results indicate that the phonological-coding deficit observed in dyslexics may be indexed by vowel length identification. Furthermore, identification results suggest that the nature of the phonological-coding deficit concomitant with dyslexia may stem from a lack of precision in processing the minimally modified longer vowel stimuli.

Disentangling dyslexia from typical L2-learning in emergent literacy.

The present paper assessed how dyslexia can be identified in school children with another language than their first language. Participants were school children with Norwegian as their second language (L2), and two groups of children with Norwegian as their first language (L1): a control group (L1-Con), and a dyslexia group (L1-Dys). All were 2nd and 3rd graders who had attended Norwegian schools from 1st grade on. None of the individuals in L1-Con or the L2 group were identified with any learning disability. However, slow literacy progress was seen in some L2-children. The children were tested individually within the symptomatic and cognitive levels. Results were analysed in two steps: (1) group comparisons; (2) L2 individual profiles and tentative L2 subgrouping. An unexpected L2 profile showed language scores below norm, coupled with some scores within and some scores above norm within the cognitive domain. Case assessment of the L2 group resulted in three subgroups: one comparable to L1-Con, one comparable to L1-Dys, and one with a result in between these two groups. Low linguistic scores cannot be considered valid markers of dyslexia in L2. Within the cognitive domain, a variety of low scores can indicate dyslexia, while high scores can be compensatory.

Resilience, Mental Flourishing, Character Strengths and Job Satisfaction of Adults with Dyslexia Compared to a Control Group

<p style="text-align: justify;">Dyslexia is traditionally regarded as a disability which has an impact on the learning process of reading, spelling and writing. This study attempts to explore the character strengths, flourishing, resilience, and perceptions of professional success and satisfaction of 477 Greek adults. The sample consisted of 30 adults with an official diagnosis of dyslexia, 103 adults who scored above the threshold limit in the Dyslexia Checklist, and 344 adults who did not report any leaning difficulty. The following instruments were employed in the study: the Brief Resilience Scale, the Flourishing Scale, and subscales of the Values in Action Inventory of Strengths 120 (creativity, perseverance, social intelligence and teamwork). The results show that the dyslexic group scored higher in creativity and teamwork in comparison to the control group. No statistical differences were observed in professional success and satisfaction between the groups. Level of education seems to correlate with creativity. The prediction models showed a negative correlation of social intelligence with suspected dyslexia and a very low prediction of flourishing and resilience on the basis of dyslexia status. Positive traits of dyslexia are worth further study. Identifying strengths among people with dyslexia might be helpful for implementing new educational interventions and strategies.</p>

An ensemble-based Machine learning technique for dyslexia detection during a visual continuous performance task

BackgroundDyslexia is a neurological disorder which affects the learning of individuals suffering from it, especially children. It causes reading and writing difficulties, leading to anger, frustration, poor self-esteem, and other negative emotions. Early diagnosis of dyslexia can be extremely useful for dyslexic children since their learning requirements can be correctly handled. MethodThis study aimed to propose an efficient method for dyslexia detection via evoked-related potentials (ERPs) during a Visual Continuous Performance Task (VCPT). To this end, after extracting the latency and amplitude of the event-related potential components and a statistical analysis between the two groups, the number of data dimensions is reduced by the KS-test and principal component analysis (PCA). This method used the ensemble learning classification technique to classify the normal and dyslexic groups, including five classifiers, namely a Support Vector Machine (SVM), Decision Tree, Linear Discriminant Analysis (LDA), K-nearest Neighbors (KNN), and Naive Bayesian. Moreover, we have used an 8-fold cross-validation method to assess how generalized the process is and, more importantly, to have a well-performed control on overfitting. ResultsAccording to this approach, the overall average classification accuracy is 87.5%, and the sensitivity and specificity are 81.2% and 93.7%, respectively. ConclusionThe suggested technique can improve children's education before they start school and have any skills in writing and reading. The most discriminative electrodes were found in the left hemisphere, which can be related to the Wernicke and Broca areas that have an essential role in the brain's reading, writing, and language-related functions.

Eye movements and the perceptual span in disordered reading: A comparison of schizophrenia and dyslexia

Increasing evidence of a common neurodevelopmental etiology between schizophrenia and developmental dyslexia suggests that neurocognitive functions, such as reading, may be similarly disrupted. However, direct comparisons of reading performance in these disorders have yet to be conducted. To address this gap in the literature, we employed a gaze-contingent moving window paradigm to examine sentence-level reading fluency and perceptual span (breadth of parafoveal processing) in adults with schizophrenia (dataset from Whitford et al., 2013) and psychiatrically healthy adults with dyslexia (newly collected dataset). We found that the schizophrenia and dyslexia groups exhibited similar reductions in sentence-level reading fluency (e.g., slower reading rates, more regressions) compared to matched controls. Similar reductions were also found for standardized language/reading and executive functioning measures. However, despite these reductions, the dyslexia group exhibited a larger perceptual span (greater parafoveal processing) than the schizophrenia group, potentially reflecting a disruption in normal foveal-parafoveal processing dynamics. Taken together, our findings suggest that reading and reading-related functions are largely similarly disrupted in schizophrenia and dyslexia, providing additional support for a common neurodevelopmental etiology.

RAN-related neural-congruency: a machine learning approach toward the study of the neural underpinnings of naming speed.

Naming speed, behaviorally measured via the serial Rapid automatized naming (RAN) test, is one of the most examined underlying cognitive factors of reading development and reading difficulties (RD). However, the unconstrained-reading format of serial RAN has made it challenging for traditional EEG analysis methods to extract neural components for studying the neural underpinnings of naming speed. The present study aims to explore a novel approach to isolate neural components during the serial RAN task that are (a) informative of group differences between children with dyslexia (DYS) and chronological age controls (CAC), (b) improve the power of analysis, and (c) are suitable for deciphering the neural underpinnings of naming speed. We propose a novel machine-learning-based algorithm that extracts spatiotemporal neural components during serial RAN, termed RAN-related neural-congruency components. We demonstrate our approach on EEG and eye-tracking recordings from 60 children (30 DYS and 30 CAC), under phonologically or visually similar, and dissimilar control tasks. Results reveal significant differences in the RAN-related neural-congruency components between DYS and CAC groups in all four conditions. Rapid automatized naming-related neural-congruency components capture the neural activity of cognitive processes associated with naming speed and are informative of group differences between children with dyslexia and typically developing children. We propose the resulting RAN-related neural-components as a methodological framework to facilitate studying the neural underpinnings of naming speed and their association with reading performance and related difficulties.

Comparison of children with and without dyslexia using functional head impulse test and pediatric balance scale.

The aim of this study is to compare functionality of vestibulo-ocular reflex (VOR) responses to evaluate the functional properties of the vestibular system and daily balance performance in children with dyslexia and children with normal development. Fifteen participants diagnosed with dyslexia were included in the study group (SG), and 15 healthy participants were included in the control group (CG). All groups underwent Functional Head Impulse Test (f-HIT) and Pediatric Balance Scale (PBS). f-HIT was performed with at least 15 head impulses at 4000-5000-6000°/s2 randomly to the right and left in the plane of the horizontal semicircular canal (SCC). Statistical analysis was performed using descriptive statistics and the Mann-Whitney U test. SG percentage values were obtained lower than CG percentage values. Comparisons between the two groups showed that there was a significant difference in all parameters (4000-5000-6000°/s2 and total) in the right-side stimulation, there was significant difference for 4,000 s2 and total correct answers in the left side. In addition, although there was no significant difference between the groups in terms of the PBS score, the SG scores were lower (p = 0.062). As a novel test, f-HIT, revealed the difference in functionality of vestibular performance in the dyslexia group. In the dyslexia group, f-HIT may be helpful in evaluating and monitoring the vestibular system.

Relationships Between First and Second Language Phonological Awareness and Rapid Automatized Naming in Chinese Children with Dyslexia

Relationships Between First and Second Language Phonological Awareness and Rapid Automatized Naming in Chinese Children with Dyslexia