Dyslexia Research Articles

Reversal errors (e.g., confusing b with d, or R with Я) are common in beginning readers and often persist in individuals with developmental dyslexia due to mirror invariance—an evolutionary-old perceptual tendency of processing mirror images as equivalent. This study investigated whether dyslexic adults still struggle with mirror-image discrimination when processing reversible letters (i.e., differing only by orientation; e.g., d, b, p) and nonreversible letters (i.e., differing also in shape; e.g., f, t, r). In a masked priming lexical decision task, one letter of the prime was manipulated by letter-type (reversible, nonreversible) and prime-condition: identity (e.g., judo, zero), control (judo, zero), mirrored-letter (jubo, zero), or rotated-letter (jupo, zero). Both dyslexic and neurotypical readers showed identity priming effects: faster recognition of target-words preceded by identity than control primes. Neurotypical readers also showed mirror and rotation costs, regardless of letter-type: slower word recognition after mirrored- or rotated-letter primes than an identity prime. In contrast, and for nonreversible letters only, dyslexics were as fast in recognizing target-words preceded by identity as by mirrored-letter primes (qualified by Bayesian statistics). These findings suggest that, despite extensive reading experience, orthographic processing by dyslexic college students remains residually sensitive to mirror invariance.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-21092-5.

Developmental dyslexia is associated with deficient temporal auditory processing, which may play an important role in speech perception, language development, and subsequently, learning to read. Music activities may offer a way to support temporal auditory processing and language and reading development. We utilized change-related mismatch negativities (MMNs) of the electroencephalogram (EEG) to study the detection of temporal pattern violations in tone sequences in 28-month-olds, and its associations with dyslexia risk, language skills, and music activities. We also considered possible effects of two infant music-listening interventions. The MMN had diminished amplitudes in dyslexia risk compared to control children in the left hemisphere, and left-hemisphere dominance was only seen in the controls. Larger MMNs were associated with better language skills and higher amount of parent-reported shared music activities, but not with the infant music-listening interventions. The results demonstrate, in line with our hypotheses, deficient processing of temporal patterns in tone sequences in familial dyslexia-risk children. Together with the positive association with language skills, this supports the relevance of temporal auditory processing for language and reading development. The association of MMNs with the frequency of shared music activities at home suggests that active, joint music making might benefit temporal auditory processing.

Rapid decay of perceptual memory in dyslexia.

Deviant functional connectivity patterns in the EEG related to developmental dyslexia and their potential use for screening.

Developmental dyslexia (DD) has been related to deficits in multiple cognitive skills. Phonological processing deficits are the most frequently reported in opaque orthographies, but there are few studies of transparent orthographies, such as Spanish. The aim of this study was to comprehensively explore possible deficiencies in cognitive functions in Spanish-speaking Mexican children with DD, to determine whether these deficits can explain problems with decoding fluency and accuracy, and analyze whether they provide support for some of the explanatory hypotheses of DD. An extensive cognitive assessment was performed with Spanish-speaking readers: 40 children (20 girls) with DD (mean age 9.02 years, SD = 1.49) and 40 children (20 girls) who were typical readers (mean age 9.22 years, SD = 1.45). Our results showed that most of the children with DD presented deficits in multiple cognitive skills, although not all of these skills contributed to reading performance. These cognitive deficits were not equally distributed among all children and there was no cognitive skill in which all participants with DD showed poor performance. Our results demonstrated that recognition of letter orientation, phonological awareness, and rapid automatized naming were significant predictors of reading ability. These findings support the idea that reading is a multifactorial process involving many cognitive skills, and its disruption could arise from different causes. The main findings are discussed in relation to the major explanatory hypotheses of DD. (PsycInfo Database Record (c) 2025 APA, all rights reserved).

Research on interventions to improve morphological awareness in children with developmental dyslexia remains sparse. This study examines whether morphological awareness intervention enhances the morphological awareness skills of Chinese children with developmental dyslexia. Thirty elementary school children with developmental dyslexia (9-10 years old) from Beijing, China, participated in this study. Fifteen children were randomly assigned to an experimental group receiving morphological awareness intervention, while another fifteen were assigned to a control group. The intervention comprised ten sessions, each lasting 40minutes. Children's morphological awareness, including homophone awareness, compounding awareness, radical awareness, and homograph awareness, was assessed before and after the delivery of the intervention. Results showed that the experimental group demonstrated significantly improved morphological awareness, particularly in homophone awareness and compounding awareness, compared to the control group. However, no significant improvements were observed in radical awareness and homograph awareness. The findings provide preliminary evidence suggesting that morphological awareness develops through distinct facets, each exhibiting differing levels of responsiveness to targeted interventions.

Background/Objectives: Executive functioning (EF) and prospective memory (PM) difficulties have been documented in adults with developmental dyslexia. However, research has tended to focus on university students with a formal diagnosis, overlooking adults who may experience symptoms of dyslexia without ever being formally diagnosed. The present online study aimed to investigate the effects of dyslexia traits on EF and PM in a larger, community-based sample by prioritising the use of self-report measures that include and differentiate between underexplored aspects of EF and PM in the dyslexia literature. Methods: One hundred and eighty adult volunteers of a wide range of ages were included in the final analysis. Participants completed four self-report questionnaires with good pedigrees assessing dyslexia traits and ADHD symptomatology, as well as everyday experiences of five distinct EFs, PM and PM strategies. Results: Hierarchical regression analyses revealed that, after controlling for age and ADHD symptomatology, more self-reported dyslexia traits were associated with more frequent EF problems overall and lower confidence in PM Abilities. Elevated dyslexia traits were significantly associated with self-reports of more difficulties with time-management, organisation and self-restraint, but not with more difficulties with motivation and regulation of emotion. No significant associations were found between dyslexia traits and the self-reported use of PM-enhancing strategies. Conclusions: The findings are considered in the light of potential metacognition deficits and theoretical and practical implications are discussed.

Introduction. A study of world experience in the field of diagnostics of reading difficulties for adults shows that there are a number of standardized tests. However, their transfer to domestic practice is a methodological problem due to the variable understanding of the term «dyslexia»; the focus of most foreign tests on reading words, not texts; the uniqueness of the linguistic characteristics of different languages. The relevance of developing standardized text tasks for a valid quantitative assessment of the reading capabilities of adults in domestic practice is due to the need to create scientifically based diagnostic methods. The purpose of this article is to analyze international diagnostic tests for assessing adult reading and to describe the main characteristics of diagnostic tools for studying reading in the Russian-speaking segment of the population.Materials and methods. Validation of the results of a pilot study of written and speech activities of students of a pedagogical university (2015-2023) and analysis of the content of foreign reading tests for adults TOWRE, GORT, YAA-R, CC2A, BDT, DAST, MDDDT-A, TIL, SLS-Berlin, NART, and the Programme for the International Assessment of Adult Competencies (PIAAC) for people aged 16-65 years made it possible to determine the main provisions of the protocol for conducting a full-scale study of reading among Russian-speaking adults.Results. A protocol for a sample study of reading characteristics of Russian-speaking people aged 16-65 was developed, inclusion and exclusion criteria were defined. We constructed a diagnostic instrument «CHITOPUS: reading test for adults». It includes four texts for reading aloud and silently. Comparison of test material by parameters: style, volume, structural and lexical complexity, readability, as well as additional comparison of propositions in texts with implicit meaning showed a balance of lexical tasks by linguostylistic characteristics.Discussion and conclusions. Insufficient development of materials in domestic practice that allow for reliable assessment of various aspects of reading in adults actualizes the need to prepare diagnostic tools for studying reading. The key aspect of diagnostics will be the definition of normative reading parameters. This requires a systematic study of various reading characteristics, including speed, accuracy, method, expressiveness and understanding of the text read. It is important to establish reference indicators, deviation from which can be interpreted as a manifestation of a disorder, possibly developmental dyslexia. The study of reading characteristics will allow replenishing data on the profiles for Russian-speaking adults with dyslexia.

How do children with developmental dyslexia in Chinese integrate sentence–picture information?

Developmental dyslexia is a neurodevelopmental disorder marked by persistent literacy difficulties. Prevailing accounts attribute dyslexic issues to impaired phonological awareness, temporal processing difficulties, or limited cognitive resources. To examine these accounts in Italian, seventy dyslexic and typically developing adolescents were recruited. The participants completed a phoneme monitoring task, responding to target consonants in strong versus weak syllables of polysyllabic nonsense strings. Rhythm-related acoustic features (duration, rise-time, intensity, F0) were measured, and patterns encoding obstruent, sonorant, and geminate contrasts were assessed. Dyslexic participants showed reduced d′-sensitivity and accuracy for all linguistic contrasts, but no acoustic feature had an effect on their performance. Instead, phoneme monitoring was moderated by attentional resources: while the typically developing group improved with increased attentional resources, the dyslexic group did not. This finding suggests that dyslexia might involve an inefficient use of shifting attention during phonological processing, possibly due to a dissociation between the two domains.

Developmental Language Disorder (DLD) and Dyslexia frequently co-occur. Many studies suggest that children with Dyslexia may also struggle with oral language skills, while those with DLD may also face challenges in word decoding. Both groups of children typically exhibit deficits in phonological processing [phonological awareness, rapid automatized naming (RAN), verbal short-term memory (VSTM)] and verbal working memory (VWM). Despite the increasing number of comparative studies, few have systematically examined these overlaps in children at the early stages of literacy acquisition, and few studies have systematically assessed all oral language subsystems. This study investigates: (a) differences and similarities among children with DLD, children at Risk of Dyslexia (RfD), and typically developing children (TD) in phonological processing (phonological awareness—implicit and explicit—VSTM, RAN), VWM, oral language, and word decoding; (b) patterns of performance across groups; and (c) correlations between phonological processing and VWM skills with oral language and word decoding. The participants were 45 first graders (Mage = 6.8), equally divided into three groups (DLD, RfD, and TD children). Both special groups (DLD, RfD) performed significantly worse than the TD group across nearly all measurements. DLD children showed pronounced oral language and VSTM deficits, while RfD children primarily struggled with decoding and explicit phonological awareness. Group-specific correlations emerged. The findings are discussed in light of the theoretical models of the relationship between DLD and Dyslexia taking into account the specific developmental stage.

Distinct neural processing underlying visual face and object perception in dyslexia.

Development of foveal crowding in typically developing children and children with developmental dyslexia.

Phonological Processing Deficits in a Child with Developmental Dyslexia- A Case Report

Reading abilities and cognitive processing in grade 3 children with ADHD comorbid with developmental dyslexia.

Effectiveness of neuromodulation with tDCS on developmental dyslexia: A randomized, double-blind, controlled clinical trial.

Background/Objectives: Developmental dyslexia is characterised by neuropsychological processing deficits and marked hemispheric functional asymmetries. To uncover latent neurophysiological features linked to reading impairment, we applied dimensionality reduction and clustering techniques to high-density electroencephalographic (EEG) recordings. We further examined the functional relevance of these features to reading performance under standardised test conditions. Methods: EEG data were collected from 200 children (100 with dyslexia and 100 age- and IQ-matched typically developing controls). Principal Component Analysis (PCA) was applied to high-dimensional EEG spectral power datasets to extract latent neurophysiological components. Twelve principal components, collectively accounting for 84.2% of the variance, were retained. K-means clustering was performed on the PCA-derived components to classify participants. Group differences in spectral power were evaluated, and correlations between principal component scores and reading fluency, measured by the TILLS Reading Fluency Subtest, were computed. Results: K-means clustering trained on PCA-derived features achieved a classification accuracy of 89.5% (silhouette coefficient = 0.67). Dyslexic participants exhibited significantly higher right parietal–occipital alpha (P8) power compared to controls (mean = 3.77 ± 0.61 vs. 2.74 ± 0.56; p < 0.001). Within the dyslexic group, PC1 scores were strongly negatively correlated with reading fluency (r = −0.61, p < 0.001), underscoring the functional relevance of EEG-derived components to behavioural reading performance. Conclusions: PCA-derived EEG patterns can distinguish between dyslexic and typically developing children with high accuracy, revealing spectral power differences consistent with atypical hemispheric specialisation. These results suggest that EEG-derived neurophysiological features hold promise for early dyslexia screening. However, before EEG can be firmly established as a reliable molecular biomarker, further multimodal research integrating EEG with immunological, neurochemical, and genetic measures is warranted.

Many individuals with normal or even above-average intelligence experience difficulties in reading, writing, and speaking without any apparent sensory or educational causes. This condition is known as dyslexia, which often goes undetected early on and has a negative impact on language learning processes. This study aims to conduct an in-depth analysis of the types of dyslexia, its neurological causes, and effective intervention strategies to minimize language barriers for individuals with dyslexia. The study employs a qualitative approach with a case study design. The research subject consists of one individual with dyslexia who exhibits significant difficulties in reading, writing, and speaking. Data was collected through direct observation, in-depth interviews, and documentation related to the subject's language development. Research instruments include interview guides and structured observation sheets. Data was analyzed using thematic analysis techniques to identify patterns of language disorders and their causal factors. The results of the study indicate that dyslexia is a neurological disorder that affects the left hemisphere of the brain responsible for language processing. Two types of dyslexia were identified: developmental dyslexia, which is genetic, and acquired dyslexia, which results from brain damage. Although it cannot be cured, the disorder can be minimized through intervention and specialized learning strategies. The study concluded that early diagnosis and individualized learning approaches are crucial for supporting literacy skills in individuals with dyslexia. The implications of this research emphasize the importance of teacher training and the provision of specialized pedagogical strategies for students with diverse learning needs.

In the present study, 43 Italian school-age children (age range = 7-14 years, 16 females) with (N = 19) and without DD (N = 24) were presented with pairs of visual displays separated by varying interstimulus intervals and performed either a temporal integration or segregation task despite an identical visual input. Children with DD had lower accuracy and slower RTs for longer temporal intervals. Additionally, efficiency (combined accuracy and speed trade-off) increased as a function of age only in the DD group, most markedly for the integration condition. Results suggest that visual temporal processing deficits in DD may depend on short-term/working memory liability as well as the existence of possibly differentiated developmental trajectories for integration and segregation abilities.

Calibrated voxel data from fMRI for the detection of developmental dyslexia using hybrid CNN-SVM model