We provide a commentary on current debates about the definition of dyslexia. We agree with others that dyslexia is best thought of as a dimensional disorder with the best established causal risk factor being a deficit in phonological processing. Dyslexia is particularly common in children from families with a history of dyslexia and in children with preschool language difficulties. We argue that definitions may differ depending upon their purpose. Traditional discrepancy definitions may be useful for research purposes, but when considering the provision of educational services discrepancy definitions are not useful since all children with reading difficulties require reading intervention regardless of their level of IQ.

We address defining and identifying students with dyslexia within the context of multi-tier systems of support (MTSS). We review proposed definitions of dyslexia, evidence for proposed definitional attributes, and emphasize the role of instructional response in identifying students with dyslexia. We identify dyslexia as individuals with specific deficits in reading and spelling single words combined with inadequate response to evidence-based instruction. We propose a hybrid identification process in which assessment is utilized within school-wide MTSS allowing for integration of routinely collected progress monitoring data as well integrating with more formal diagnostic measures. This proposed "hybrid" method demonstrates strong evidence for valid decision-making and directly informs instruction. We close proposing a revised definition of dyslexia that incorporates these elements.

Here we build from the central strength of the existing definition of dyslexia-its emphasis on neurobiological origins-and proffer a set of seven core principles for a new, more comprehensive conceptualization of dyslexia. These principles derive from two major research directions: (1) the still evolving history of attempts to explain dyslexia, including in varied writing systems; and (2) the study of the reading brain circuit, its development, and its genetic and environmental influences. What emerges from connecting these two directions is a dynamic conceptualization of dyslexia that incorporates the extensive research on the heterogeneity of dyslexia and the interdependent contributions of multiple biological and socio-cultural risk and preventive factors. A new definition of dyslexia, therefore, needs to transcend both past unitary characterizations and past assumptions based largely on the English orthography. Such a conceptualization references the ways that different languages interact with the reading brain circuit to produce different sources of reading failure. Similarly, the characteristics and consequences of dyslexia that have been considered as secondary sequela (e.g., reduced reading comprehension, social-emotional issues) should be part of a more comprehensive narrative. Of critical importance, any definition of dyslexia should clarify persisting misconceptions that associate dyslexia with a lack of intelligence, potential to learn, or talents. Thus, the overall purpose of such a definition should serve as an instrument of knowledge and an enduring reason for pursuing growth in reading for the individual, the educator, and the public.

Two decades after the International Dyslexia Association (IDA) adopted the 2002 consensus definition of dyslexia, this special issue of the Annals of Dyslexia revisits that definition in light of advances in scientific understanding and evolving needs. Through contributions from leading researchers and interdisciplinary teams, the issue examines the strengths and limitations of the definition as it has been applied in research, policy, and practice. Key themes emerged, which included reconsidering the need to include the neurobiological basis of dyslexia in the definition, the intersection of literacy challenges and mental health, and the role of context in shaping how dyslexia is defined. Contributors to this special issue also reflected on how the definition serves different audiences, including educators, policymakers, and families. As the IDA embarks on a thoughtful reassessment of the 2002 definition, this collection of articles offers insights to guide the path forward, ensuring the definition remains a robust tool for research, identification, intervention, and advocacy in the coming years.

In offering a commentary upon the IDA definition, we address its main components in turn. While each is technically accurate, we argue that, when taken together, the definition, or more accurately, the use to which it is often put, becomes problematic. We outline different current conceptions of dyslexia and conclude that the operationalisation of the definition for diagnostic purposes often results in scientifically questionable diagnoses and inadvertently leads to significant educational inequity. We propose a simpler definition that describes the primary difficulty, avoids reference to causal explanation, unexpectedness, and secondary outcomes, and redirects practitioner and policymaker focus to the importance of addressing and meeting the needs of all struggling readers.

This commentary article describes the results of a Delphi Method discussion between an interdisciplinary team of state dyslexia policy implementers. The authors argue that the International Dyslexia Association (IDA) definition of dyslexia from 2001 skews toward the perspectives of the research community, inadvertently creating implementation challenges for school practice. The article describes how the authors reached this determination; why they believe Vaughn et al.'s (Annals of Dyslexia, 2024) proposed definition marks an improvement over the 2001 IDA definition; and the need for continued support in the dyslexia policy implementation process, including knowledge dissemination efforts and updates to other relevant policy documents. This collaboration between policymakers, educators, and researchers contributes to the special issue by considering how the definition of dyslexia is situated in policy and practice. In so doing, it addresses a longstanding gap in academic research on how policy implementers understand and use the IDA definition.

Excessive crowding in the visual periphery has been demonstrated in children with developmental dyslexia (DD). However, less is known about crowding in the fovea, even though foveal crowding is at least equally important, as reading is mostly accomplished through foveal vision. Here we used a special set of digit stimuli (Pelli fonts) to measure foveal crowding in DD and DD + ADHD children, and compared it to that in TD (typically developing) and ADHD children. We also used the Chinese reading acuity charts (C-READ) to assess the maximum reading speed and reading acuity, along with tests to evaluate cognitive attributes including phonological awareness, rapid automatized naming, morphological awareness, and orthographic knowledge. The results indicate significantly stronger foveal crowding in the DD and DD + ADHD groups, as well as in the ADHD group, than in the TD group. Furthermore, the DD and DD + ADHD groups exhibited poorer maximum reading speed and reading acuity compared to the ADHD and TD groups. Within the two DD groups, the slower maximum reading speed and higher reading acuity can be predicted by stronger foveal crowding. In addition, the DD and DD + ADHD groups performed the worst in four cognitive skills, with the DD group showing negative correlations between foveal crowding and performances across all these skills. Our findings thus move beyond previously well-documented peripheral crowding in dyslexia, and the easy administration of the Pelli-font-based crowding test may be useful for early diagnosis of developmental dyslexia in young children.

While developmental dyslexia has been extensively studied in children, research on adults is still rather limited. This paper aims to bridge the gap in existing research by presenting the findings of a study that examined the reading and spelling skills of adults with dyslexia and assessed the effectiveness of a linguistic intervention designed to improve their literacy abilities. To address this issue, we first compared the profiles of 44 adults with dyslexia (age range: 16-30 y.o.) and 44 age-matched typical readers across tasks assessing reading, spelling, phonological awareness, morphological awareness and lexical access in Italian. The findings underscored pervasive impairments in dyslexia across all measured dimensions, reaffirming the persistent nature of language and literacy challenges into adulthood. In pursuit of the second objective, the study explored the potential for literacy skill improvement in adults with dyslexia through the implementation of a specialized intervention proposed to 24 dyslexic adults and delivered via a web application. The intervention program yielded positive outcomes in the experimental group, demonstrating significant improvements in word and text reading, spelling, and speed of phonological elaboration. This study, hence, contributes not only to our understanding of developmental dyslexia in adulthood but also emphasizes the tangible benefits of targeted linguistic interventions, thereby offering practical implications for the amelioration of literacy skills in this population.

This study examined six reading intervention teachers' implementation of the SPELL-Links to Reading and Writing intervention with students in Grades 2 and 3. The purpose was to explore the extent to which teachers who received a one-day training session without ongoing coaching support were able to implement the intervention with fidelity. It also aimed to better understand the determinants (i.e., barriers and facilitators) of teachers' implementation and their perceptions related to the importance, feasibility, and effectiveness of the intervention. Data from four sources (implementation logs, implementation observations, interviews, and surveys) were collected and analyzed. Participating teachers did not implement the intervention at the intended dosage of 4 days per week, but they did demonstrate high adherence and quality on average. Several barriers to implementation were identified, including intervention training, intervention content and structure, compatibility with existing practices, and alignment with goals. Notable facilitators of implementation were teacher capability and peer support. Teachers had varying perceptions of the intervention, with neutral satisfaction on average. These findings indicate a need for further research on determinants of intervention implementation as they may be crucial in supporting teachers' implementation fidelity.

Early identification plays a crucial role in providing timely support to students with learning disabilities, such as dyslexia, in order to overcome their reading difficulties. However, there is significant variability in the methods used for identifying dyslexia. This study aimed to explore and understand the practices of dyslexia identification in the UK. A survey was conducted among 274 dyslexia professionals, including educational psychologists and dyslexia specialists, to investigate the types of assessments they employ, their approach to utilizing assessment data, their decision-making processes, and their conceptualization of dyslexia. Additionally, the study examined whether these professionals held any misconceptions or myths associated with dyslexia. Analysis of the survey data revealed substantial variability in how professionals conceptualize dyslexia, as well as variations in assessment methods. Furthermore, a significant proportion of the survey respondents subscribed to one or more misconceptions regarding dyslexia; the most common misconception identified among professionals was the belief that children with dyslexia read letters in reverse order. The findings highlight the need for standardized approaches to dyslexia identification and debunking prevailing misconceptions. The implications of these findings are discussed, emphasizing the importance of informed policy and practice in supporting students with dyslexia. Recommendations are provided to enhance consistency and accuracy in dyslexia identification, with the aim of facilitating early intervention and support for affected students.

Due to pandemic-induced lockdown(s) in 2020, dyslexia treatment was forced to move to online platforms. This study examined whether Dutch children who received online treatment progressed as much in their reading and spelling performance as children who received the usual face-to-face treatment. To this end, 254 children who received treatment-as-usual were compared to 162 children who received online treatment with Bayesian methods. The advantage of a Bayesian approach is that it can provide evidence for and against the null hypothesis whereas frequentist approaches only provide evidence against it. We found that children in the online treatment condition received slightly fewer treatment sessions but progressed equally after controlling for the number of sessions compared to the treatment-as-usual condition. These results have clinical and practical implications as they show that reading treatment can be successfully delivered online.

This study examined the cognitive-linguistic and literacy-related correlates of dyslexia in three Chinese cities and the English word reading and mathematics performances of Chinese children with dyslexia. Chinese children with/without dyslexia were measured with an equivalent test battery of literacy and mathematics in Beijing, Hong Kong, and Taipei. Univariate analysis results suggested that phonological sensitivity distinguished those with and without dyslexia across all three cities in group comparisons. In Taipei and Hong Kong, morphological awareness, delayed copying, and spelling also distinguished the groups. Logistic regression analyses demonstrated that Chinese character reading, as directly compared to Chinese word reading, also distinguished the groups particularly well. In addition, in Beijing and Hong Kong, children with dyslexia performed significantly less well in English word reading than those without dyslexia. In Hong Kong and Taipei, children with dyslexia also had difficulties in mathematics performance. Findings highlight the fundamental importance of some cognitive-linguistic skills for explaining Chinese dyslexia across cultures, the utility of recognizing the individual Chinese character as a foundational unit of analysis in Chinese across cultures, and the generalizability of the comorbidity of both English as a second language (L2) and mathematics with dyslexia in Chinese children in both Beijing and Hong Kong.

Learning to read is a middle-distance race for children worldwide. Most of them succeed in this acquisition with "normal" difficulties that ensue from the progressive (re)structuring of the phonological and orthographic systems. Evidence accumulated on reading difficulties in children with developmental dyslexia (DYS children, henceforth) shows a pervasive phonological deficit. However, the phonological deficit may not be due to degraded phonological representations but rather due to impaired access to them. This study focused on how and to what extent phonological syllables, which are essential reading units in French, were accessible to DYS children to segment and access words. We tested the assumption that DYS children did not strictly have pervasive degraded phonological representations but also have impaired access to phonological and orthographic representations. We administered a visually adapted word-spotting paradigm, engaging both sublexical processing and lexical access, with French native-speaking DYS children (N = 25; M = 121.6, SD = 3.0) compared with chronological age-matched peers (N = 25; M = 121.8, SD = 2.7; CA peers henceforth) and reading level-matched peers (N = 25; M = 94.0, SD = 4.6; RL peers henceforth). Although DYS children were slower and less accurate than CA and RL peers, we found that they used phonological syllables to access and segment words. However, they exhibit neither the classical inhibitory syllable frequency effect nor the lexical frequency effect, which is generally observed in typically developing children. Surprisingly, DYS children did not show strictly degraded phonological representations because they demonstrated phonological syllable-based segmentation abilities, particularly with high-frequency syllables. Their difficulties are rather interpreted in terms of impaired access to orthographic and phonological representations, which could be a direct effect of difficulties in generalizing and consolidating low-frequency syllables. We discuss these results regarding reading acquisition and the specificities of the French linguistic system.

Rapid automatized naming (RAN) has surged in popularity recently as an important indicator of reading difficulties, including dyslexia. Despite an extensive history of research on RAN, including recent meta-analyses indicating a unique contribution of RAN to reading above and beyond phonemic awareness, questions remain regarding RAN's relationship to reading. Specific questions exist regarding how PA mediates that relationship and how best to use data from RAN measures to identify risk for reading failure. Through multiple studies, we demonstrate that RAN is not merely subsumed by skills typically assessed when conducting universal screening for reading difficulties (i.e., phonemic segmentation fluency and letter naming fluency), but contributes unique information above and beyond these measures. Additionally, we discuss the process for the development of cut points for risk for Acadience RAN, along with guidance regarding how educators can interpret RAN scores as an indicator of risk for future reading difficulties. The results presented here support the idea that difficulties associated with RAN are not merely reflections of difficulties with other early literacy skills typically assessed during universal screening, but constitute separate and distinct difficulties that may precipitate later reading problems.

Dyslexia, characterized by word reading and spelling deficits, has historically been viewed through a medical model of disability. However, a countermovement has emerged, emphasizing the strengths and abilities of neurodiverse individuals, including those with dyslexia. The concept of neurodiversity, which was initially introduced to help inform understanding of a mild form of autism, has expanded to include dyslexia. The expansion has occurred alongside a similar portrayal of dyslexia as an advantage that comes with specific gifts, creating a positive stereotype. While intended to empower individuals with dyslexia, the translation of the concept of neurodiversity to dyslexia in this way can inadvertently stigmatize and isolate those who do not fit this positive stereotype of dyslexia. This review, following a perspective review article format, synthesizes existing literature on the purported gifts of dyslexia and the implications of both negative and positive stereotypes on the well-being of individuals with dyslexia. The findings of this review underscore the importance of dispelling myths about dyslexia and advocating against the use of stereotypes, both negative and positive, in portraying dyslexia. Doing so will help remove the harmful effects of stigmatization, stereotype threat, and the potential of a fixed mindset inherent to being stereotyped.

Reading proficiency is important because it has life-long consequences and influences success in other academic areas. Many students with behavior problems are poor readers and many students with learning disabilities have more behavior problems than their typical peers. We conducted a correlational meta-analysis to examine the association between reading and externalizing behavior in students ages 5-12. We identified 33 studies that reported 88 effect sizes. Using a random-effects linear regression model with robust variance estimation, we found a significant, negative correlation (r= -0.1698, SE = 0.01, p < 0.0001) between reading and externalizing behavior. We tested several moderators related to measurement and sample characteristics. We found that rater type, behavior dimension (e.g., aggression), time between longitudinal measurement points, age of the sample, and percentage male of the sample moderated the relation between reading and behavior. Whether the reading assessment measured comprehension or word reading and socioeconomic status of the sample did not moderate the relation. Understanding the association between reading and externalizing behavior has implications for disability identification and intervention practices for children in elementary school. Future research should examine shared cognitive factors and environmental influences that explain the relation between the constructs.

The purpose of this longitudinal study was to examine the development of spelling in a large sample (N = 503, boys: N = 219) of Greek-speaking children with (N = 41) and without (N = 462) reading difficulties. Children were initially tested in Grades 2-4 and then at five consecutive measurement points over a 3-year period, focusing on how initial reading ability, grade, and gender may moderate the rate of spelling growth. Individual growth curve modeling revealed continuous growth of spelling performance in the total sample, although the growth rate decreased over time for children first tested in Grades 3-4. Spelling growth rate was also significantly slower among children with reading difficulties between Grades 2-4 and 3-5. The two reading groups displayed similar growth rates between Grades 4 and 6. Spelling growth rates did not vary significantly with gender. Overall, our study highlights the persistence of spelling difficulties even after 6 years of systematic teaching in children with reading difficulties. The severe and persistent spelling deficits of Greek-speaking children with reading difficulties may be attributed to the rich morphological system of the Greek language, the intermediate Greek orthographic transparency (in the direction of writing), and their limited experience with print.

This study examined the relations between reading anxiety, general anxiety, and test anxiety in a sample of students with reading difficulties (n = 536). It also tested if dimensions of anxiety were differentially related to word reading accuracy and fluency, text reading fluency, or reading comprehension. The results indicated that the three anxiety measures were significantly related (r = 0.51 to 0.56, p < .001). Additionally, higher reading anxiety was related to poorer word reading fluency, text reading fluency, and comprehension outcomes. Further analyses indicated that these relations existed in students who fell in the middle and upper quantiles for reading, but not the lowest quantile. This pattern of findings suggests that the relation is complex and varies depending on severity of reading difficulty. Results may help to inform future efforts to support students with reading difficulties, including students with dyslexia.