Longitudinal relationships between speech perception, phonological skills and reading in children at high-risk of dyslexia

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

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.

Do early musical impairments predict later reading difficulties? A longitudinal study of pre-readers with and without familial risk for dyslexia

The present longitudinal study investigated the hypothesis that early musical skills (as measured by melodic and rhythmic perception and memory) predict later literacy development via a mediating effect of phonology. We examined 130 French-speaking children, 31 of whom with a familial risk for developmental dyslexia (DD). Their abilities in the three domains were assessed longitudinally with a comprehensive battery of behavioral tests in kindergarten, first grade, and second grade. Using a structural equation modeling approach, we examined potential longitudinal effects from music to literacy via phonology. We then investigated how familial risk for DD may influence these relationships by testing whether atypical music processing is a risk factor for DD. Results showed that children with a familial risk for DD consistently underperformed children without familial risk in music, phonology, and literacy. A small effect of musical ability on literacy via phonology was observed, but may have been induced by differences in stability across domains over time. Furthermore, early musical skills did not add significant predictive power to later literacy difficulties beyond phonological skills and family risk status. These findings are consistent with the idea that certain key auditory skills are shared between music and speech processing, and between DD and congenital amusia. However, they do not support the notion that music perception and memory skills can serve as a reliable early marker of DD, nor as a valuable target for reading remediation. RESEARCH HIGHLIGHTS: Music, phonology, and literacy skills of 130 children, 31 of whom with a familial risk for dyslexia, were examined longitudinally. Children with a familial risk for dyslexia consistently underperformed children without familial risk in musical, phonological, and literacy skills. Structural equation models showed a small effect of musical ability in kindergarten on literacy in second grade, via phonology in first grade. However, early musical skills did not add significant predictive power to later literacy difficulties beyond phonological skills and family risk status.

Reading Skill Profiles in School-Aged Italian-Speaking Children: A Latent Profile Analysis Investigation into the Interplay of Decoding, Comprehension and Attentional Control

Our study examined the complex relationships among reading performance (decoding, comprehension) and language, visuo-spatial, and attentional control abilities in 115 Italian-speaking children. Latent profile analysis was used to identify distinct clusters of participants showcasing quantitative differences in decoding skills, including word, pseudo-word, text reading speed and accuracy. Then, we used this classification to investigate group differences in a variety of linguistic, working memory, and visuo-spatial tasks, as well as in reading comprehension skills, by means of multivariate and univariate tests. Our results reveal significant links between reading proficiency and several key factors: language skills, visuo-spatial abilities, and attentional control. These findings illuminate the nuanced impact of domain-general processes that govern a series of linguistic and visuo-perceptive subcomponents during reading tasks. Additionally, using dominance analysis, predictors of written text comprehension were identified. Our findings suggest that effective reading comprehension relies on a synergistic interplay of adequate reading speed, attentional control, working memory, and verbal fluency, accounting for 23% of the explained variance. This study highlights the multifaceted nature of reading proficiency and suggests that a broader perspective is necessary to fully understand reading development and support its improvement.

Dynamics of cognitive predictors during reading acquisition in a sample of children overrepresented for dyslexia risk

Literacy acquisition is a complex process with genetic and environmental factors influencing cognitive and neural processes associated with reading. Previous research identified factors that predict word reading fluency (WRF), including phonological awareness (PA), rapid automatized naming (RAN), and speech-in-noise perception (SPIN). Recent theoretical accounts suggest dynamic interactions between these factors and reading, but direct investigations of such dynamics are lacking. Here, we investigated the dynamic effect of phonological processing and speech perception on WRF. More specifically, we evaluated the dynamic influence of PA, RAN, and SPIN measured in kindergarten (the year prior to formal reading instruction), first grade (the first year of formal reading instruction) and second grade on WRF in second and third grade. We also assessed the effect of an indirect proxy of family risk for reading difficulties using a parental questionnaire (Adult Reading History Questionnaire, ARHQ). We applied path modeling in a longitudinal sample of 162 Dutch-speaking children of whom the majority was selected to have an increased family and/or cognitive risk for dyslexia. We showed that parental ARHQ had a significant effect on WRF, RAN and SPIN, but unexpectedly not on PA. We also found effects of RAN and PA directly on WRF that were limited to first and second grade respectively, in contrast to previous research reporting pre-reading PA effects and prolonged RAN effects throughout reading acquisition. Our study provides important new insights into early prediction of later word reading abilities and into the optimal time window to target a specific reading-related subskill during intervention.

Longitudinal Predictors of Word Reading for Children with Williams Syndrome

We examined the cognitive, language, and instructional predictors of early word-reading ability in a sample of children with Williams syndrome longitudinally. At Time 1, sixty-nine 6-7-year-olds (mean age = 6.53 years) completed standardized measures of phonological awareness, visual-spatial perception, vocabulary, and overall intellectual ability. Word-reading instruction type was classified as (systematic) Phonics (n = 35) or Other (n = 34). At Time 2, approximately three years later (mean age = 9.47 years), children completed a standardized assessment of single-word reading ability. Reading ability at Time 2 varied considerably, from inability to read any words to word-reading ability slightly above the level expected for age. The results of a multiple regression indicated that Time 1 word-reading instruction type, phonological awareness, and visual-spatial perception (as assessed by a matching letter-like forms measure) each explained significant unique variance in word reading at Time 2. A systematic phonics approach was associated with significantly better performance than other reading-instruction approaches. Exploratory analyses suggested that the relations between these factors were complex. Considered together, these findings strongly suggest that, in line with the Cumulative Risk and Resilience Model of reading disability, word-reading (dis)ability in Williams syndrome is probabilistic in nature, resulting from the interaction of multiple individual and environmental risk and protective factors. The results also have educational implications: Early word-reading instruction for children with Williams syndrome should combine systematic phonics and phonological awareness training while also incorporating letter discrimination instruction highlighting the visual-spatial differences between similar-appearing letters.

Language and reading impairments are associated with increased prevalence of non-right-handedness

Handedness has been studied for association with language-related disorders because of its link with language hemispheric dominance. No clear pattern has emerged, possibly because of small samples, publication bias, and heterogeneous criteria across studies. Non-right-handedness (NRH) frequency was assessed in N = 2503 cases with reading and/or language impairment and N = 4316 sex-matched controls identified from 10 distinct cohorts (age range 6-19 years old; European ethnicity) using a priori set criteria. A meta-analysis (Ncases  = 1994) showed elevated NRH % in individuals with language/reading impairment compared with controls (OR = 1.21, CI = 1.06-1.39, p = .01). The association between reading/language impairments and NRH could result from shared pathways underlying brain lateralization, handedness, and cognitive functions.

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.

Language-specific phonological skills and the relationship with reading accuracy in Sylheti-English sequential bilinguals

This study investigated the influence of first language (L1) phonology on second language (L2) early reading skills in Sylheti-English bilinguals (N = 58; 48% girls; British Bangladeshi) and their monolingual-English peers (N = 43; 45% girls; 96% White British, 4% multiethnic British) in a diaspora context. Language-specific phonological awareness and nonword repetition were tested at two time points (6;2-7;8 years-old). At Time 1, the bilinguals had lower productive accuracy for phonological sequences that violated their L1 phonology (d = .56; .84), and these skills accounted for a significant amount of variance in their reading accuracy. At Time 2, the language-specific effects were no longer present. These findings highlight the importance of considering language structure in multilingual early literacy development.

Categorical perception of Mandarin lexical tones in language-delayed autistic children

Enhanced pitch perception has been identified in autistic individuals, but it remains understudied whether such enhancement can be observed in the lexical tone perception of language-delayed autistic children. This study examined the categorical perception of Mandarin lexical tones in 23 language-delayed autistic children and two groups of non-autistic children, with one matched on chronological age ( n = 23) and the other on developmental age in language ability ( n = 23). The participants were required to identify and discriminate lexical tones. A wider identification boundary width and a lower between-category discrimination accuracy were found in autistic children than their chronological-age-matched non-autistic peers, but the autistic group exhibited seemingly comparable performance to the group of developmental-age-matched non-autistic children. While both non-autistic groups displayed a typical categorical perception pattern with enhanced sensitivity to between-category tone pairs relative to within-category ones, such a categorical perception pattern was not observed in the autistic group. These findings suggest among language-delayed autistic children with a developmental age around 4, categorical perception is still developing. Finally, we found categorical perception performance correlated with language ability, indicating autistic children’s language disability might be predictive of their poor categorical perception of speech sounds.

Lay abstract

Some theories suggested that autistic people have better pitch perception skills than non-autistic people. However, in a context where pitch patterns are used to differentiate word meanings (i.e. lexical tones), autistic people may encounter difficulties, especially those with less language experience. We tested this by asking language-delayed autistic children to identify and discriminate two Mandarin lexical tones (/yi/ with Tone 1, meaning ‘clothes’; /yi/ with Tone 2, meaning ‘aunt’; /yi/: the standard romanization of Mandarin Chinese). On average, these autistic children were 7.35 years old, but their developmental age in language ability was 4.20, lagging behind 7-year-old non-autistic children in terms of language ability. Autistic children’s performance in identifying and discriminating lexical tones was compared with two groups of non-autistic children: one group was matched with the autistic group on age, and the other was matched based on language ability. Autistic children performed differently from the non-autistic children matched on age, while autistic and non-autistic children matched on language ability exhibited seemingly similar performance. However, both the non-autistic groups have developed the perceptual ability to process lexical tones as different categories, but this ability was still developing in autistic children. Finally, we found autistic children who performed worse in identifying lexical tones had poorer language ability. The results suggest that language disability might have adverse influence on the development of skills of speech sound processing.

Late mismatch negativity of lexical tone at age 8 predicts Chinese children’s reading ability at age 10

Background

Deficits in phonological processing are commonly reported in dyslexia but longitudinal evidence that poor speech perception compromises reading is scant. This 2-year longitudinal ERP study investigates changes in pre-attentive auditory processing that underlies categorical perception of mandarin lexical tones during the years children learn to read fluently. The main purpose of the present study was to explore the development of lexical tone categorical perception to see if it can predict children’s reading ability.

Methods

Both behavioral and electrophysiological measures were taken in this study. Auditory event-related potentials were collected with a passive listening oddball paradigm. Using a stimulus continuum spanning from one lexical tone category exemplar to another, we identified a between-category and a within-category tone deviant that were acoustically equidistant from a standard stimulus. The standard stimulus occurred on 80% of trials, and one of two deviants (between-category or within-category) equiprobably on the remaining trials. 8-year-old Mandarin speakers participated in both an initial ERP oddball paradigm and returned for a 2-year follow-up.

Results

The between-category MMN and within-category MMN significantly correlate with each other at age 8 (p = 0.001) but not at age 10. The between-category MMN at age 8 can predict children’s ability at age 10 (p = 0.03) but the within-category cannot.

Conclusion

The categorical perception of lexical tone is still developing from age 8 to age 10. The behavioral and electrophysiological results demonstrate that categorical perception of lexical tone at age 8 predicts children’s reading ability at age 10.

Speech Perception Variability in Childhood Apraxia of Speech: Implications for Assessment and Intervention

PURPOSE

Beyond hallmark production deficits characterizing childhood apraxia of speech (CAS), largely attributed to disruption(s) in speech motor planning, children with CAS often present with co-occurring speech perception and language difficulties. Thus, careful consideration of the potential for speech perception difficulties to have cascading downstream effects on intervention responsiveness and real-life functioning for some children with CAS is highly important. The purpose of this tutorial was to consider the impact of speech perception abilities in children with CAS, which carries implications for caring for the needs of the whole child.

METHOD

This tutorial summarizes the current literature on speech perception and how it relates to speech production, language, and reading abilities for children with CAS. We include case illustrations that are adapted from real clinical scenarios illustrating how speech perception difficulties may impact some children with CAS and provide recommendations for incorporating speech perception into assessment and intervention practices.

RESULTS

Although speech perception difficulties do not seem to be a core deficit of CAS, they are strongly linked to language difficulties, which are highly prevalent among children with CAS. Speech perception and language difficulties are also associated with reading difficulties and risk for lower academic achievement.

CONCLUSIONS

Children with CAS who have co-occurring language difficulties likely also demonstrate speech perception deficits, which puts them at heightened risk for reading difficulties and struggles with academic achievement. Comprehensive assessment of children with CAS should address speech perception and production, language, and reading abilities, which carries important implications for multifaceted approaches to intervention.

Visuo-spatial attention deficit in children with reading difficulties

Although developmental reading disorders (developmental dyslexia) have been mainly associated with auditory-phonological deficits, recent longitudinal and training studies have shown a possible causal role of visuo-attentional skills in reading acquisition. Indeed, visuo-attentional mechanisms could be involved in the orthographic processing of the letter string and the graphemic parsing that precede the grapheme-to-phoneme mapping. Here, we used a simple paper-and-pencil task composed of three labyrinths to measure visuo-spatial attention in a large sample of primary school children (n = 398). In comparison to visual search tasks requiring visual working memory, our labyrinth task mainly measures distributed and focused visuo-spatial attention, also controlling for sensorimotor learning. Compared to typical readers (n = 340), children with reading difficulties (n = 58) showed clear visuo-spatial attention impairments that appear not linked to motor coordination and procedural learning skills implicated in this paper and pencil task. Since visual attention is dysfunctional in about 40% of the children with reading difficulties, an efficient reading remediation program should integrate both auditory-phonological and visuo-attentional interventions.

Later but Not Weaker: Neural Categorization of Native Vowels of Children at Familial Risk of Dyslexia

Although allophonic speech processing has been hypothesized to be a contributing factor in developmental dyslexia, experimental evidence is limited and inconsistent. The current study compared the categorization of native similar sounding vowels of typically developing (TD) children and children at familial risk (FR) of dyslexia. EEG response was collected in a non-attentive passive oddball paradigm from 35 TD and 35 FR Dutch 20-month-old infants who were matched on vocabulary. The children were presented with two nonwords “giep” [ɣip] and “gip” [ɣIp] that contrasted solely with respect to the vowel. In the multiple-speaker condition, both nonwords were produced by twelve different speakers while in the single-speaker condition, single tokens of each word were used as stimuli. For both conditions and for both groups, infant positive mismatch response (p-MMR) was elicited, and the p-MMR amplitude was comparable between the two groups, although the FR children had a later p-MMR peak than the TD children in the multiple-speaker condition. These findings indicate that FR children are able to categorize speech sounds, but that they may do so in a more effortful way than TDs.

Allophonic perception of VOT contrasts in Spanish children with dyslexia

INTRODUCTION

Previous studies have evidenced a different mode of speech perception in dyslexia, characterized by the use of allophonic rather than phonemic units. People with dyslexia perceive phonemic features (such as voicing) less accurately than typical readers, but they perceive allophonic features (i.e., language-independent differences between speech sounds) more accurately.

METHOD

In this study, we investigated the perception of voicing contrasts in a sample of 204 Spanish children with or without dyslexia. Identification and discrimination data were collected for synthetic sounds varying along three different voice onset time (VOT) continua (ba/pa, de/te, and di/ti). Empirical data will be contrasted with a mathematical model of allophonic perception building up from neural oscillations and auditory temporal processing.

RESULTS

Children with dyslexia exhibited a general deficit in categorical precision; that is, they discriminated among phonemically contrastive pairs (around 0-ms VOT) less accurately than did chronological age controls, irrespective of the stimulus continuum. Children with dyslexia also exhibited a higher sensitivity in the discrimination of allophonic features (around ±30-ms VOT), but only for the stimulus continuum that was based on a nonlexical contrast (ba/pa).

CONCLUSION

Fitting the neural network model to the data collected for this continuum suggests that allophonic perception is due to a deficit in "subharmonic coupling" between high-frequency oscillations. Relationships with "temporal sampling framework" theory are discussed.

Annual Research Review: Reading disorders revisited - the critical importance of oral language

This paper discusses research on reading disorders during the period since their classification within the overarching category of neurodevelopmental disorders (Journal of Child Psychology and Psychiatry, 53, 2012, 593). Following a review of the predictors of learning to read across languages, and the role of language skills as critical foundations for literacy, profiles of reading disorders are discussed and putative causal risk factors at the cognitive, biological, and environmental levels of explanation considered. Reading disorders are highly heritable and highly comorbid with disorders of language, attention, and other learning disorders, notably mathematics disorders. The home literacy environment, reflecting gene-environment correlation, is one of several factors that promote reading development and highlight an important target for intervention. The multiple deficit view of dyslexia (Cognition, 101, 2006, 385) suggests that risks accumulate to a diagnostic threshold although categorical diagnoses tend to be unstable. Implications for assessment and intervention are discussed.

Unveiling the Mysteries of Dyslexia-Lessons Learned from the Prospective Jyväskylä Longitudinal Study of Dyslexia

This paper reviews the observations of the Jyväskylä Longitudinal Study of Dyslexia (JLD). The JLD is a prospective family risk study in which the development of children with familial risk for dyslexia (N = 108) due to parental dyslexia and controls without dyslexia risk (N = 92) were followed from birth to adulthood. The JLD revealed that the likelihood of at-risk children performing poorly in reading and spelling tasks was fourfold compared to the controls. Auditory insensitivity of newborns observed during the first week of life using brain event-related potentials (ERPs) was shown to be the first precursor of dyslexia. ERPs measured at six months of age related to phoneme length identification differentiated the family risk group from the control group and predicted reading speed until the age of 14 years. Early oral language skills, phonological processing skills, rapid automatized naming, and letter knowledge differentiated the groups from ages 2.5-3.5 years onwards and predicted dyslexia and reading development, including reading comprehension, until adolescence. The home environment, a child's interest in reading, and task avoidance were not different in the risk group but were found to be additional predictors of reading development. Based on the JLD findings, preventive and intervention methods utilizing the association learning approach have been developed.

Beyond Reading Modulation: Temporo-Parietal tDCS Alters Visuo-Spatial Attention and Motion Perception in Dyslexia

Dyslexia is a neurodevelopmental disorder with an atypical activation of posterior left-hemisphere brain reading networks (i.e., temporo-occipital and temporo-parietal regions) and multiple neuropsychological deficits. Transcranial direct current stimulation (tDCS) is a tool for manipulating neural activity and, in turn, neurocognitive processes. While studies have demonstrated the significant effects of tDCS on reading, neurocognitive changes beyond reading modulation have been poorly investigated. The present study aimed at examining whether tDCS on temporo-parietal regions affected not only reading, but also phonological skills, visuo-spatial working memory, visuo-spatial attention, and motion perception in a polarity-dependent way. In a within-subjects design, ten children and adolescents with dyslexia performed reading and neuropsychological tasks after 20 min of exposure to Left Anodal/Right Cathodal (LA/RC) and Right Anodal/Left Cathodal (RA/LC) tDCS. LA/RC tDCS compared to RA/LC tDCS improved text accuracy, word recognition speed, motion perception, and modified attentional focusing in our group of children and adolescents with dyslexia. Changes in text reading accuracy and word recognition speed—after LA/RC tDCS compared to RA/LC—were related to changes in motion perception and in visuo-spatial working memory, respectively. Our findings demonstrated that reading and domain-general neurocognitive functions in a group of children and adolescents with dyslexia change following tDCS and that they are polarity-dependent.

School-entry language outcomes in late talkers with and without a family risk of dyslexia

Children with familial risk (FR) of dyslexia and children with early language delay are known to be at risk for later language and literacy difficulties. However, research addressing long-term outcomes in children with both risk factors is scarce. This study tracked FR and No-FR children identified as late talkers at 2 years of age and reports development from 4;6 through 6 years. We examined the possible effects of FR-status and late talking (LT) status, respectively, on language skills at school entry, and whether FR-status moderated the associations between 4;6-year and 6-year language scores. Results indicated an effect of LT status on language at both ages, while FR status affected language skills at 6 years only. The interaction between LT and FR statuses was not significant, implying that LT status affected language skills independently of the child's FR status. A proportion of late talkers developed typical language at 6 years of age, while some FR children with typical vocabulary skills in toddlerhood had emerging developmental language disorder by school entry. FR status had a moderating effect on the association between expressive grammar at ages 4;6 and 6 years. Possible explanations for the effect of FR status on language skills are discussed. We highlight limitations in the study size and suggest how these preliminary findings can inform future research.

Action Video Games Enhance Attentional Control and Phonological Decoding in Children with Developmental Dyslexia

Reading acquisition is extremely difficult for about 5% of children because they are affected by a heritable neurobiological disorder called developmental dyslexia (DD). Intervention studies can be used to investigate the causal role of neurocognitive deficits in DD. Recently, it has been proposed that action video games (AVGs)-enhancing attentional control-could improve perception and working memory as well as reading skills. In a partial crossover intervention study, we investigated the effect of AVG and non-AVG training on attentional control using a conjunction visual search task in children with DD. We also measured the non-alphanumeric rapid automatized naming (RAN), phonological decoding and word reading before and after AVG and non-AVG training. After both video game training sessions no effect was found in non-alphanumeric RAN and in word reading performance. However, after only 12 h of AVG training the attentional control was improved (i.e., the set-size slopes were flatter in visual search) and phonological decoding speed was accelerated. Crucially, attentional control and phonological decoding speed were increased only in DD children whose video game score was highly efficient after the AVG training. We demonstrated that only an efficient AVG training induces a plasticity of the fronto-parietal attentional control linked to a selective phonological decoding improvement in children with DD.

Manual dexterity predicts phonological decoding speed in typical reading adults

Manual dexterity and phonological decoding involve the posterior parietal cortex, which controls location coding for visually guided actions, as well as a large fronto-cerebellar network. We studied the relationship between manual dexterity and reading ability in adult typical readers. Two measurements of manual dexterity were collected to index the procedural learning effect. A linear regression model demonstrated that phonological short-term memory, manual dexterity at time 1 and procedural learning of manual dexterity predicted phonological decoding speed. Similar results were found when left-hand dexterity at time 1 and procedural learning dexterity were entered last. The better one's phonological decoding skill was, the less fluent their manual dexterity was, suggesting a recycle from object-location to letter-location coding. However, the greater the procedural learning, the faster phonological decoding was, suggesting that larger plasticity of object-location coding was linked to better letter-location coding. An independent role of the interhemispheric connections or of the right posterior parietal cortex is also suggested.

Dysfunctional auditory gamma oscillations in developmental dyslexia: A potential target for a tACS-based intervention

Interventions in developmental dyslexia typically consist of orthography-based reading and writing trainings. However, their efficacy is limited and, consequently, the symptoms persist into adulthood. Critical for this lack of efficacy is the still ongoing debate about the core deficit in dyslexia and its underlying neurobiological causes. There is ample evidence on phonological as well as auditory temporal processing deficits in dyslexia and, on the other hand, cortical gamma oscillations in the auditory cortex as functionally relevant for the extraction of linguistically meaningful information units from the acoustic signal. The present work aims to shed more light on the link between auditory gamma oscillations, phonological awareness, and literacy skills in dyslexia. By mean of EEG, individual gamma frequencies were assessed in a group of children and adolescents diagnosed with dyslexia as well as in an age-matched control group with typical literacy skills. Furthermore, phonological awareness was assessed in both groups, while in dyslexic participants also reading and writing performance was measured. We found significantly lower gamma peak frequencies as well as lower phonological awareness scores in dyslexic participants compared to age-matched controls. Additionally, results showed a positive correlation between the individual gamma frequency and phonological awareness. Our data suggest a hierarchical structure of neural gamma oscillations, phonological awareness, and literacy skills. Thereby, the results emphasize altered gamma oscillation not only as a core deficit in dyslexia but also as a potential target for future causal interventions. We discuss these findings considering non-invasive brain stimulation techniques and suggest transcranial alternating current stimulation as a promising approach to normalize dysfunctional oscillations in dyslexia.

Remediation of a phonological representation deficit in Chinese children with dyslexia: A comparison between metalinguistic training and working memory training

A form-preparation task in the language production field was adopted to examine output phonological representations in Chinese dyslexia and their susceptibility to training. Forty-one Chinese children with dyslexia (7-11 years old) and 36 chronological age controls completed this task. The controls demonstrated a marginally significant syllable facilitation effect (d = -0.13), indicating their use of syllable-sized phonological representations during speech production, while the group with dyslexia showed a significantly different pattern (d = 0.04), opposite to the direction of a facilitation effect. The children with dyslexia were then randomly assigned to either metalinguistic training (N = 22) or working memory training (N = 19). Only the metalinguistic training subgroup demonstrated a significant syllable facilitation effect afterward (metalinguistic: d = -0.13; working memory: d = -0.01). The results suggest the presence of a phonological representation deficit at the syllable level in Chinese dyslexia and its possible remediation by metalinguistic training. Such a phonological deficit in readers of a logographic script strongly supports the impaired phonological representation view of developmental dyslexia. A video abstract of this article can be viewed at https://youtu.be/zT2Be0xMkh0.

Bridging sensory and language theories of dyslexia: Toward a multifactorial model

Competing theories of dyslexia posit that reading difficulties arise from impaired visual, auditory, phonological, or statistical learning mechanisms. Importantly, many theories posit that dyslexia reflects a cascade of impairments emanating from a single “core deficit”. Here we report two studies evaluating core deficit and multifactorial models. In Study 1, we use publicly available data from the Healthy Brain Network to test the accuracy of phonological processing measures for predicting dyslexia diagnosis and find that over 30% of cases are misclassified (sensitivity = 66.7%; specificity = 68.2%). In Study 2, we collect a battery of psychophysical measures of visual motion processing and standardized measures of phonological processing in 106 school‐aged children to investigate whether dyslexia is best conceptualized under a core‐deficit model, or as a disorder with heterogenous origins. Specifically, by capitalizing on the drift diffusion model to analyze performance on a visual motion discrimination experiment, we show that deficits in visual motion processing, perceptual decision‐making, and phonological processing manifest largely independently. Based on statistical models of how variance in reading skill is parceled across measures of visual processing, phonological processing, and decision‐making, our results challenge the notion that a unifying deficit characterizes dyslexia. Instead, these findings indicate a model where reading skill is explained by several distinct, additive predictors, or risk factors, of reading (dis)ability.

Context effects on phoneme categorization in children with dyslexia

Research shows that, on average, children with dyslexia behave less categorically in phoneme categorization tasks. This study investigates three subtle ways that struggling readers may perform differently than their typically developing peers in this experimental context: sensitivity to the frequency distribution from which speech tokens are drawn, bias induced by previous stimulus presentations, and fatigue during the course of the task. We replicate findings that reading skill is related to categorical labeling, but we do not find evidence that sensitivity to the stimulus frequency distribution, the influence of previous stimulus presentations, and a measure of task engagement differs in children with dyslexia. It is, therefore, unlikely that the reliable relationship between reading skill and categorical labeling is attributable to artifacts of the task design, abnormal neural encoding, or executive function. Rather, categorical labeling may index a general feature of linguistic development whose causal relationship to literacy remains to be ascertained.

The Prevalence of Dyslexia in Primary School Children and Their Chinese Literacy Assessment in Shantou, China

The epidemiological studies of Chinese developmental dyslexia (DD) in China are still limited. In addition, literacy assessment has seldom been performed for children with dyslexia, due to lack of uniform assessment tools. This study was aimed at investigating the prevalence rate of children with dyslexia, and to evaluate their Chinese reading ability. A total of 2955 students aged 7-12 years were enrolled by randomized cluster sampling. The study was divided into three stages. In stage I, all participating students were asked to finish the Combined Raven Test (CRT) and Chinese Vocabulary Test and Assessment Scale. In stage II, the Chinese teachers and parents of the children with suspected dyslexia were interviewed by psychiatrists, and finished the Dyslexia Checklist for Chinese Children (DCCC). In stage III, these children were evaluated by child psychiatrists for the diagnosis with or without dyslexia, according to the fifth edition of Diagnostic and Statistical Manual of Mental Disorders (DSM-5), and their Chinese literacy was further evaluated by using the Chinese Reading Ability Test (CRAT). The prevalence rate of children with dyslexia was 5.4% in Shantou city, 8.4% in boys and 2.3% in girls, with a gender ratio of 3.7:1.0. Children with dyslexia scored lower in all the five subscales of the CRAT tests. including phonological awareness, morphological awareness, rapid automatized naming, orthographic awareness, and reading ability than the control group (all p < 0.001). This study suggested that the prevalence rate of Chinese dyslexia in Shantou city is roughly equivalent to that previously reported in China. Children with dyslexia have a relatively lower Chinese reading ability in all assessments.

Lexical and grammatical development in children at family risk of dyslexia from early childhood to school entry: a cross-lagged analysis

The aim of this study was to examine (a) the development of vocabulary and grammar in children with family-risk (FR) of dyslexia and their peers with no such risk (NoFR) between ages 1;6 and 6;0, and (b) whether FR-status exerted an effect on the direction of temporal relationships between these two constructs. Groups were assessed at seven time-points using standardised tests and parental reports. Results indicated that although FR and NoFR children had a similar development in the earlier years, the FR group appeared to perform significantly more poorly on vocabulary at the end of the preschool period. Results showed no significant effect of FR status on the cross-lagged relations between lexical and grammatical skills, suggesting a similar developmental pattern of cross-domain relations in both groups. However, FR status seemed to have a significantly negative association with vocabulary and grammar scores at age 6;0, resulting in language outcomes in favour of NoFR children.

The effectiveness of an intervention program -barton intervention program- on reading fluency of Iranian students with dyslexia

BACKGROUND

Difficulty with reading fluency has been increasingly acknowledged as a significant aspect of reading disabilities which is called dyslexia. To investigate this important issue, this research aims to examine the impact of an intervention program on reading fluency of dyslexic students.

MATERIALS AND METHODS

The research is an experimental one. The population of the study included all the second- and third-grade male and female students in the city of Ilam, Iran, among whom 68 students were recognized to be dyslexic using a screening inventory reading test (IRT) developed by Shafiei et al., in 2009, they were selected using purposeful sampling method. The students were equally divided and assigned into a control and an experimental group. The experimental group received the Barton intervention program for 10 weeks. The reading fluency test was administered for the measurement of reading fluency in pre- and post-tests. Data were analyzed using descriptive statistics (mean and standard deviation) and paired t-test.

RESULTS

The analysis of the finding through t-test found a statistically significant difference between the control and experimental groups after the intervention program at P < 0.01.

CONCLUSIONS

The results revealed that the students who received the intervention program of the experimental group were improved in terms of their reading fluency.

Longitudinal relationships between speech perception, phonological skills and reading in children at high-risk of dyslexia

Speech perception deficits are commonly reported in dyslexia but longitudinal evidence that poor speech perception compromises learning to read is scant. We assessed the hypothesis that phonological skills, specifically phoneme awareness and RAN, mediate the relationship between speech perception and reading. We assessed longitudinal predictive relationships between categorical speech perception, phoneme awareness, RAN, language, attention and reading at ages 5½ and 6½ years in 237 children many of whom were at high risk of reading difficulties. Speech perception at 5½ years correlated with language, attention, phoneme awareness and RAN concurrently and was a predictor of reading at 6½ years. There was no significant indirect effect of speech perception on reading via phoneme awareness, suggesting that its effects are separable from those of phoneme awareness. Children classified with dyslexia at 8 years had poorer speech perception than age-controls at 5½ years and children with language disorders (with or without dyslexia) had more severe difficulties with both speech perception and attention control. Categorical speech perception tasks tap factors extraneous to perception, including decision-making skills. Further longitudinal studies are needed to unravel the complex relationships between categorical speech perception tasks and measures of reading and language and attention.