Developmental surface and phonological dyslexia in both Greek and English

Effects of central vs. peripheral attentional-oculomotor exercise on lexical processing

Past research from our lab has suggested visual demands in video games serve to exercise attentional-oculomotor (A-O) processing in a manner beneficial to reading. However, testing the effect of video games on reading typically requires long timeframes (e.g., multiweek training or years of accumulated video game experience). The current study manipulated within-experiment peripheral and central demands to evaluate the effects of A-O exercise on task performance. Our study included two tasks: an orthographic lexical decision task (OLDT), designed to optimise orthographic lexical processing, and a novel graphic-based health bar decision task (HBDT). In Experiment 1, the stimuli were presented centrally in one block and peripherally in another block to manipulate A-O exercise. We observed greater improvements in the peripheral-first than the central-first group, particularly for the OLDT. In Experiments 2 and 3, we focused on the OLDT, with the HBDT serving as the A-O exercise task, and observed improvements in both centrally and peripherally trained participants. We additionally observed, through analyses of word and bigram frequency, a double dissociation, whereby increased target word frequency was associated with faster target reaction times and improved error rates, whereas increased foil bigram frequency was associated with slower foil reaction times and worse error rates. Taken together, the experiments demonstrate a mechanism beyond simple task learning that drives reading improvements, and A-O exercise, even if movements are small, appears to play a role in the improvements observed. We suggest future research should further develop this paradigm and examine its utility for reading remediation in dyslexia.

Multiple Types of Developmental Dyslexias in a Shallow Orthography: Principles for Diagnostic Screening in Italian

A new dyslexia screening test for Italian, Tiltan-IT, is presented. The test was developed based on an integrated dual-route model of reading, which describes in detail specific mechanisms underpinning early visual processes as well as the lexical and the sublexical routes. The principle according to which the test was developed is that each dyslexia type is manifested in different kinds of errors and in different kinds of stimuli, and we therefore included stimuli sensitive to each dyslexia type in the test. Tiltan-IT is a reading aloud test that includes word, nonword, and word pair lists. The test was administered to 618 Italian-speaking children (2nd-8th grade). Each error produced by the children was classified through the coding scheme developed to detect the different types of dyslexias described by the reading model. The Tiltan-IT was able to identify 110 children with dyslexia. The identified dyslexia types included letter position dyslexia, attentional dyslexia, letter identity dyslexia, surface dyslexia, vowel dyslexia, consonant conversion dyslexia, multi-letter phonological dyslexia, voicing dyslexia. The results confirm that the selection of items in the Tiltan-IT enabled the detection of the wide variety of dyslexias in Italian, some of them for the first time, adding evidence for the cross-linguistic validity of multiple types of developmental dyslexias and for the dual-route model of reading.

Characterizing different types of developmental dyslexias in French: The Malabi screener

Reading is a complex process involving multiple stages. An impairment in any of these stages may cause distinct types of reading deficits- distinct types of dyslexia. We describe the Malabi, a screener to identify deficits in various orthographic, lexical, and sublexical components of the reading process in French. The Malabi utilizes stimuli that are sensitive to different forms of dyslexia, including "attentional dyslexia", as it is traditionally refered to, characterized by letter-to-word binding impairments leading to letter migrations between words (e.g., "bar cat" misread as "bat car"), and "letter-position dyslexia", resulting in letter transpositions within words (e.g., "destiny" misread as "density"). After collecting reading error norms from 138 French middle-school students, we analyzed error types of 16 students with developmental dyslexia. We identified three selective cases of attentional dyslexia and one case of letter-position dyslexia. Further tests confirmed our diagnosis and demonstrate, for the first time, how these dyslexias are manifested in French. These results underscore the significance of recognizing and discussing the existence of multiple dyslexias, both in research contexts when selecting participants for dyslexia studies, and in practical settings where educators and practitioners work with students to develop personalized support. The test and supporting materials are available on Open Science Framework (https://osf.io/3pgzb/).

Tracking reading skills and reading-related skills in dyslexia before (age 5) and after (ages 10-17) diagnosis

This study had three goals: to examine the stability of deficits in the phonological and lexical routes in dyslexia (group study), to determine the prevalence of dyslexia profiles (multiple-case study), and to identify the prediction of phonemic segmentation and discrimination skills before reading acquisition on future reading level. Among a group of 373 non-readers seen at age 5, 38 students were subsequently diagnosed as either consistent dyslexic readers (18 DYS) or consistent typical readers (20 TR). Their phonological and lexical reading skills were assessed at ages 10 and 17 and their phonemic segmentation and discrimination skills at age 5. In comparison with TR of the same chronological age (CA-TR), individuals with dyslexia demonstrated an impairment of the two reading routes, especially of the phonological reading route. In the comparison with younger TR (age 10) of the same reading level (RL-TR), only a deficit of the phonological route is observed. In the multiple-case study, the comparisons with CA-TR showed a prevalence of mixed profiles and very few dissociated profiles, whereas the comparison with RL-TR resulted mostly in two profiles depending on the measure: a phonological profile when accuracy was used and a delayed profile when speed was used. In addition, the correlations between early phonemic segmentation and discrimination skills (age 5) and later reading skills (age 17) were significant, and in the group of individuals with dyslexia, early phonemic segmentation skills significantly predicted these later reading skills. Phonological reading deficits are persistent and mainly caused by early phonemic impairments.

The Prevalence and Associated Risk Factors of Children With Reading Disabilities in a Multiethnic City: A Cross-Sectional Study

Numerous studies have been conducted to explore the risk factors for reading disabilities (RDs) among children. Based on these studies, factors such as gender, socioeconomic status, and the home literacy environment have been widely found to be associated with children who have RDs. However, children from a multiethnic city are seldom investigated. This study aimed to explore the prevalence of RDs and the potential environmental risk factors in Shihezi, Xinjiang, where people of multiple ethnicities, including Han and ethnic minority children, live and study together. A cross-sectional study was conducted in the city of Shihezi. A two-stage sampling strategy was applied to randomly select six primary schools in the city. In total, 6,539 students in grades two to six participated in this study. There were 6,065 valid questionnaires obtained for further analyses. We used the Dyslexia Checklist for Chinese Children and the Pupil Rating Scale to screen for the children with RDs. The χ² test and multivariate logistic regression were employed to reveal the potential risk factors of RDs. The prevalence of children with RDs was 3.38% in Shihezi City and was significantly different between Han (3.28%) and Uighur (7.42%) children (P < 0.05). There was no significant difference in the prevalence of RDs between Han and Hui children. Among these children with RDs, the gender ratio of boys to girls was nearly 2:1. Multiple logistic regression analysis showed that gender (P < 0.01), learning habits (P < 0.01), and the home literacy environment (P < 0.01) were associated with RD. The results may be useful in the early identification and intervention of children with RDs, especially among ethnic minorities.

Vowel dyslexia in Turkish: A window to the complex structure of the sublexical route

We report on developmental vowel dyslexia, a type of dyslexia that selectively affects the reading aloud of vowel letters. We identified this dyslexia in 55 Turkish-readers aged 9-10, and made an in-depth multiple-case analysis of the reading of 17 participants whose vowel dyslexia was relatively selective. These participants made significantly more vowel errors (vowel substitution, omission, migration, and addition) than age-matched controls, and significantly more errors in vowel letters than in consonants. Vowel harmony, a pivotal property of Turkish phonology, was intact and the majority of their vowel errors yielded harmonic responses. The transparent character of Turkish orthography indicates that vowel dyslexia is not related to ambiguity in vowel conversion. The dyslexia did not result from a deficit in the phonological-output stage, as the participants did not make vowel errors in nonword repetition or in repeating words they had read with a vowel error. The locus of the deficit was not in the orthographic-visual-analyzer either, as their same-different decision on words differing in vowels was intact, and so was their written-word comprehension. They made significantly more errors on nonwords than on words, indicating that their deficit was in vowel processing in the sublexical route. Given that their single-vowels conversion was intact, and that they showed an effect of the number of vowels, we conclude that their deficit is in a vowel-specific buffer in the sublexical route. They did not make vowel errors within suffixes, indicating that suffixes are converted as wholes in a separate sublexical sub-route. These results have theoretical implications for the dual-route model: they indicate that the sublexical route converts vowels and consonants separately, that the sublexical route includes a vowel buffer, and a separate morphological conversion route. The results also indicate that types of dyslexia can be detected in transparent languages given detailed error-analysis and dyslexia-relevant stimuli.

Foreign Language Attainment of Children/Adolescents with Poor Literacy Skills: a Systematic Review and Meta-analysis

This systematic review investigated how successful children/adolescents with poor literacy skills learn a foreign language compared with their peers with typical literacy skills. Moreover, we explored whether specific characteristics related to participants, foreign language instruction, and assessment moderated scores on foreign language tests in this population. Overall, 16 studies with a total of 968 participants (poor reader/spellers: n = 404; control participants: n = 564) met eligibility criteria. Only studies focusing on English as a foreign language were available. Available data allowed for meta-analyses on 10 different measures of foreign language attainment. In addition to standard mean differences (SMDs), we computed natural logarithms of the ratio of coefficients of variation (CVRs) to capture individual variability between participant groups. Significant between-study heterogeneity, which could not be explained by moderator analyses, limited the interpretation of results. Although children/adolescents with poor literacy skills on average showed lower scores on foreign language phonological awareness, letter knowledge, and reading comprehension measures, their performance varied significantly more than that of control participants. Thus, it remains unclear to what extent group differences between the foreign language scores of children/adolescents with poor and typical literacy skills are representative of individual poor readers/spellers. Taken together, our results indicate that foreign language skills in children/adolescents with poor literacy skills are highly variable. We discuss the limitations of past research that can guide future steps toward a better understanding of individual differences in foreign language attainment of children/adolescents with poor literacy skills.

Developmental surface dysgraphia without surface dyslexia

The case is reported of an individual (N.K.) with a developmental spelling impairment (dysgraphia) who has no apparent problems in reading. His performance therefore provides further evidence of a classical dissociation between impaired spelling and preserved reading in individuals with developmental literacy problems. The dissociation is observed when N.K. is asked to read and spell in either his first (Greek) or his second language (English). An investigation of his spelling performance revealed that his impairment was more selective than that of P.J.T. Although his spelling of regular words and nonwords was normal, N.K. had a problem in spelling words with atypical sound-letter associations despite having no problems in reading aloud or understanding the meaning of words of this kind. It is argued that N.K.'s pattern of performance can be best explained in terms of normal development of an orthographic system that allows access to the meaning and pronunciation of written words during reading. In terms of a dual-route model of spelling, his poor spelling appears to be the result of a developmental impairment that impedes access to the orthographic system from phonology and semantics. In terms of the triangle model, his poor spelling appears to be the result of a developmental impairment that affects activation of orthography from semantics.

Intervention for a lexical reading and spelling difficulty in two Greek-speaking primary age children

An intervention study was carried out with two nine-year-old Greek-speaking dyslexic children. Both children were slow in reading single words and text and had difficulty in spelling irregularly spelled words. One child was also poor in non-word reading. Intervention focused on spelling in a whole-word training using a flashcard technique that had previously been found to be effective with English-speaking children. Post-intervention assessments conducted immediately at the end of the intervention, one month later and then five months later showed a significant improvement in spelling of treated words that was sustained over time. In addition, both children showed generalisation of improvement to untrained words and an increase in scores in a standardised spelling assessment. The findings support the effectiveness of theoretically based targeted intervention for literacy difficulties.

Do reading and spelling share orthographic representations? Evidence from developmental dysgraphia

Both spelling and reading depend on knowledge of the spellings of words. Despite this commonality, observed dissociations between spelling and reading in cases of acquired and developmental deficits suggest some degree of independence between the cognitive mechanisms involved in these skills. In this paper, we examine the relationship between spelling and reading in two children with developmental dysgraphia. For both children, we identified significant deficits in spelling that affected the processing of orthographic long-term memory representations of words. We then examined their reading skills for similar difficulties. Even with extensive testing, we found no evidence of a reading deficit for one of the children. We propose that there may be an underlying difficulty that specifically affects the learning of orthographic word representations for spelling. These results lead us to conclude that at least some components of lexical orthographic representation and processing develop with considerable independence in spelling and reading.