Developmental dyslexia: exploring how much phonological and visual attention span disorders are linked to simultaneous auditory processing deficits

An abbreviated Chinese dyslexia screening behavior checklist for primary school students using a machine learning approach

To increase early identification and intervention of dyslexia, a prescreening instrument is critical to identifying children at risk. The present work sought to shorten and validate the 30-item Mandarin Dyslexia Screening Behavior Checklist for Primary School Students (the full checklist; Fan et al., , 19, 521-527, 2021). Our participants were 15,522 Mandarin-Chinese-speaking students and their parents, sampled from classrooms in grades 2-6 across regions in mainland China. A machine learning approach (lasso regression) was applied to shorten the full checklist (Fan et al., , 19, 521-527, 2021), constructing grade-specific brief checklists first, followed by a compilation of the common brief checklist based on the similarity across grade-specific checklists. All checklists (the full, grade-specific brief, and common brief versions) were validated and compared with data in our sample and an external sample (N = 114; Fan et al., , 19, 521-527, 2021). The results indicated that the six-item common brief checklist showed consistently high reliability (αs > .82) and reasonable classification performance (about 60% prediction accuracy and 70% sensitivity), comparable to that of the full checklist and all grade-specific brief checklists across our current sample and the external sample from Fan et al., , 19, 521-527, (2021). Our analysis showed that 2.42 (out of 5) was the cutoff score that helped classify children's reading status (children who scored higher than 2.42 might be considered at risk for dyslexia). Our final product is a valid, accessible, common brief checklist for prescreening primary school children at risk for Chinese dyslexia, which can be used across grades and regions in mainland China.

Visual attention span deficit in developmental dyslexia: A meta-analysis

BACKGROUND

Visual attention span (VAS) refers to the number of visual elements processed simultaneously in a multielement array. Yet, there are mixed findings regarding VAS deficit in developmental dyslexia (DD) across different tasks, stimuli, languages, control groups, and ages.

AIM

The present meta-analysis aimed to investigate VAS deficit in DD and factors moderating VAS deficit in DD.

METHODS

A meta-analysis based on 32 articles, 54 independent studies, and 4211 subjects was conducted. Effect sizes for each study were calculated and a random-effect model was selected. Task and stimulus types in the VAS task, writing system, orthographic depth, control group type, and age were included as possible moderators.

RESULTS

1) VAS in dyslexic individuals was significantly worse than typically developing individuals; 2) Task-stimulus type (report-verbal/n-back-verbal/n-back-nonverbal), writing system (alphabetic vs. Chinese), and control group type (age matched vs. reading matched) significantly moderated VAS deficit in DD. VAS deficit was more severe in report task with verbal stimuli than in n-back task with verbal and nonverbal stimuli. VAS deficit was more severe in alphabetic language than in Chinese. VAS deficit was more severe when compared with age-matched controls than compared with reading-matched controls.

CONCLUSION

VAS deficit is a possible etiology for DD and moderated by task-stimulus type, writing system, and control group type. These findings have important implications for the understanding of DD.

The Role of Visual Factors in Dyslexia

What are the causes of dyslexia? Decades of research reflect a determined search for a single cause where a common assumption is that dyslexia is a consequence of problems with converting phonological information into lexical codes. But reading is a highly complex activity requiring many well-functioning mechanisms, and several different visual problems have been documented in dyslexic readers. We critically review evidence from various sources for the role of visual factors in dyslexia, from magnocellular dysfunction through accounts based on abnormal eye movements and attentional processing, to recent proposals that problems with high-level vision contribute to dyslexia. We believe that the role of visual problems in dyslexia has been underestimated in the literature, to the detriment of the understanding and treatment of the disorder. We propose that rather than focusing on a single core cause, the role of visual factors in dyslexia fits well with risk and resilience models that assume that several variables interact throughout prenatal and postnatal development to either promote or hinder efficient reading.

Visual attention span capacity in developmental dyslexia: A meta-analysis

The visual attention span (VAS) deficit theory of developmental dyslexia (DD) indicates that impaired VAS may cause reading disabilities. However, whether people with dyslexia have VAS deficit is still controversial. The current review evaluates the literature regarding the relationship between VAS and poor reading, as it also examines the possible moderators in measuring the VAS capacity of individuals with dyslexia. A total of 25 papers, with participants of 859 readers with dyslexia and 1048 typically developing readers were included in the meta-analysis. The sample sizes, means and standard deviations (SDs) of the scores in VAS tasks were extracted separately from the two groups, which were used to calculate the effect sizes of group differences in SDs and means by the robust variance estimation model. Results showed higher SDs and lower averages of the VAS test scores for readers with dyslexia than those for typically developing readers, revealing high individual variability and remarkable deficits in VAS of DD. Further subgroup analyses showed that the characteristics of VAS tasks, background languages, and participants modulated the group differences in VAS capacities. Particularly, the partial report task with symbols of relatively high visual complexity and key pressing may be the optimal measurement of VAS skills. A greater VAS deficit in DD was observed in more opaque languages, with a trend of developmental increase in attention deficit, especially at the primary school level. Moreover, this VAS deficit seemed to be independent of the phonological deficit of dyslexia. These findings to some extent supported the VAS deficit theory of DD and (partially) explained the controversial relationship between VAS impairment and reading disabilities.

Dichotic listening deficits in children with hearing loss

PURPOSE

This correlational study compared dichotic listening among children with significant hearing loss to typically developing children and children clinically assessed for auditory processing disorder.

METHOD

Recorded versions of two dichotic tests were delivered under earphones or in the sound field for children using amplification. Individual ear scores and interaural asymmetry were compared to normative data. Matched deficit patterns from both tests were identified, ranked for severity of deficit, and compared across groups. Relationships between dichotic scores and factors related to amplification were investigated in the children with hearing loss.

RESULTS

Dichotic scores were significantly poorer among children with hearing loss without the large interaural asymmetries seen in children assessed clinically for auditory processing problems. Device type and age of implantation had no effect on scores; non-dominant ear scores on the digits test were significantly correlated to age of device use in the left ear and duration of device use in the right ear. Non-dominant ear scores with digits were also significantly correlated with bilateral word recognition.

CONCLUSIONS

Poor dichotic perception in children with significant hearing losses may be related to the use of recorded test materials, immature skills in attention and working memory, or other factors that contribute to development of vocabulary and language. These weaknesses may interfere with successful mainstream educational placement in these children. Assessment of dichotic performance in this population could lead to deficit-specific interventions that may improve outcomes and enhance educational opportunities for children with hearing loss.

Enhanced reading abilities is modulated by faster visual spatial attention

Research has shown improved reading following visual magnocellular training in individuals with dyslexia. Many studies have demonstrated how the magnocellular pathway controls visual spatial attention. Therefore, we have investigated the relationship between magnocellular pathway and visual spatial attention deficits in dyslexia in order to better understand how magnocellular-based interventions may help children to learn to read. Magnocellular function, visual spatial attention, and reading abilities of thirty elementary school students with dyslexia, aged between 8 and 10, were measured. The experimental group received magnocellular-based visual motion training for 12 sessions, while the control group received neutral sessions. All tests were repeated at the end of the training and after 1 month. The magnocellular functioning, visual spatial attention, and reading abilities of the experimental group improved significantly compared to the controls. Additionally, improvement in reaction time of invalid conditions predicted improvements in saccadic eye movements. We conclude that visual magnocellular training improved saccadic eye movement control, visual spatial orientation, and reading ability.

Spatial attention in encoding letter combinations

Reading requires the correct identification of letters and letter positions within words. Selective attention is, therefore, required to select chunks of the text for sequential processing. Despite the extensive literature on visual attention, the well-known effects of spatial cues in simple perceptual tasks cannot inform us about the role of attention in a task as complex as reading. Here, we systematically manipulate spatial attention in a multi-letter processing task to understand the effects of spatial cues on letter encoding in typical adults. Overall, endogenous (voluntary) cue benefits were larger than exogenous (reflexive). We show that cue benefits are greater in the left than in the right visual field and larger for the most crowded letter positions. Endogenous valid cues reduced errors due to confusing letter positions more than misidentifications, specifically for the most crowded letter positions. Therefore, shifting endogenous attention along a line of text is likely an important mechanism to alleviate the effects of crowding on encoding letters within words. Our results help set the premise for constructing theories about how specific mechanisms of attention support reading development in children. Understanding the link between reading development and attention mechanisms has far-reaching implications for effectively addressing the needs of children with reading disabilities.

Orthographic depth and developmental dyslexia: a meta-analytic study

Cross-cultural studies have suggested that reading deficits in developmental dyslexia (DD) can be moderated by orthographic depth. To further explore this issue and assess the moderating role of orthographic depth in the developmental cognitive trajectories of dyslexic and typical readers, we systematically reviewed 113 studies on DD that were published from 2013 to 2018 and selected 79 in which participants received an official DD diagnosis. Each study was classified according to orthographic depth (deep vs. shallow) and participant age (children vs. adults). We assessed the difference between DD and control groups' performance in reading tasks and in a wide range of cognitive domains associated with reading (phonological awareness (PA), rapid automatized naming (RAN), short-term working memory (WM), and nonverbal reasoning), including age and orthographies as moderators. We found an age-by-orthography interaction effect in word reading accuracy and a significant effect of age in pseudoword reading accuracy, but we found no effect of age and orthographic depth on the fluency parameters. These results suggest that reading speed is a reliable index for discriminating between DD and control groups across European orthographies from childhood to adulthood. A similar pattern of results emerged for PA, RAN, and short-term/WM. Our findings are discussed in relation to their impact on clinical practice while considering the orthographic depth and developmental level.

The role of visual-spatial attention in reading development: a meta-analysis

The association between visual attention and reading development has been investigated as a possible core causal deficit in dyslexia, in addition to phonological awareness. This study aims to provide a meta-analytic review of the research on attentional processes and their relation to reading development, to examine the possible influence on it of orthographic depth, age, and attentional tasks (interpreted as serial or parallel processing indices). We included studies with participants up to 18 years of age that have considered the visual spatial attention orienting that sustains the serial visual analysis involved in the phonological pathway of decoding, and the visual attention span that supports the multielement parallel processing that is thought to influence lexical decoding. The results confirm a strong association between visual attention and reading development; we evaluate the evidence and discuss the possibility that visual attention processes play a causal role in determining individual differences in reading acquisition.

Phonological Awareness as the Foundation of Reading Acquisition in Students Reading in Transparent Orthography

Phonological skills have been found to be strongly related to early reading and writing development. Accordingly, the aim of this study was to examine the extent to which the development of phonological awareness facilitates reading acquisition in students learning to read a transparent orthography. Our research included 689 primary school students in first through third grade (Mean age 101.59 months, SD = 12,690). The assessment tools used to conduct this research include the Phonological Awareness Test and the Gray Oral Reading Test. According to the results from the present study, 13.7% of students have reading difficulties. Students with reading difficulties obtained low scores in phonological awareness within each subscale compared to students who do not have reading difficulties (p < 0.01). Components of phonological awareness which did not singled out as strongly related to early reading success include Phoneme Segmentation, Initial Phoneme Identification, and Syllable Merging. Thus, understanding the nature of the relationship between phonological awareness and reading should help effective program design that will be aimed at eliminating delayed development in children's phonological awareness while they are still in preschool.

The influence of the multimedia and modality principles on the learning outcomes, satisfaction, and mental effort of college students with and without dyslexia

The purpose of this study was to examine the application of the multimedia and modality principles on cued-recall, recognition, and mental effort of college students with and without dyslexia. The study used a Multimedia (Image Present vs. Image Absent) × Modality (Narration vs. Onscreen Text) × Dyslexia (Dyslexia vs. Non-Dyslexia) 3-way factorial design with each independent variable serving as a between-subject condition. A total of N = 148 participants (73 with dyslexia and 75 without dyslexia) were recruited from five different institutions of higher education in the Southeastern United States and systematically assigned to one of four multimedia learning conditions. After assessing our data for statistical assumptions, we employed factorial Analysis of Variance (ANOVA) models on each dependent measure. Our findings show a reverse modality effect for students with dyslexia who performed better than their peers without dyslexia in Onscreen Text conditions. Although performance was better across groups and conditions when images were present, there were no significant interactions related to the multimedia condition. Similarly, there were no significant interactions related to mental effort even though learners with dyslexia exhibited high instructional efficiency in the Onscreen Text-Image Present condition while learners without dyslexia exhibited low task involvement in the Onscreen Text-Image Absent condition. Our results provide theoretical implications and important avenues for future research and practice as related to how multimedia learning influences students with dyslexia. We also suggest studies that could inform the eventual design of adaptive and personalized multimedia learning solutions for learners with dyslexia.

Modality and redundancy effects, and their relation to executive functioning in children with dyslexia

Children with dyslexia are often provided with audio-support to compensate for their reading problems, but this may intervene with their learning. The aim of the study was to examine modality and redundancy effects in 21 children with dyslexia, compared to 21 typically developing peers (5^th grade), on study outcome (retention and transfer knowledge) and study time in user-paced learning environments and the role of their executive functions (verbal and visual working memory, inhibition, and cognitive flexibility) on these effects. Results showed no effects on retention knowledge. Regarding transfer knowledge, a modality effect in children with dyslexia was found, and a reversed redundancy effect in typically developing children. For transfer knowledge, written text with pictures supported knowledge gain in typically developing children, but not in children with dyslexia who benefited more from auditory-presented information with pictures. Study time showed modality and reversed redundancy effects in both groups. In all children, studying in a written text with pictures condition took longer than with audio replacing the text or being added to it. Results also showed that executive functions were related to learning, but they did not differ between the groups, nor did they impact the found modality and redundancy effects. The present research thus shows that, irrespectively of children's executive functions, adding audio-support for all children, can potentially lead to more efficient learning.

The modality and redundancy effects in multimedia learning in children with dyslexia

The present study aimed to examine the modality and redundancy effects in multimedia learning in children with dyslexia in order to find out whether their learning benefits from written and/or spoken text with pictures. We compared study time and knowledge gain in 26 11-year-old children with dyslexia and 38 typically reading peers in a within-subjects design. All children were presented with a series of user-paced multimedia lessons in 3 conditions: pictorial information presented with (a) written text, (b) audio, or (c) combined text and audio. We also examined whether children's learning outcomes were related to their working memory. With respect to study time, we found modality and reversed redundancy effects. Children with dyslexia spent more time learning in the text condition, compared with the audio condition and the combined text-and-audio condition. Regarding knowledge gain, no modality or redundancy effects were evidenced. Although the groups differed on working memory, it did not influence the modality or redundancy effect on study time or knowledge gain. In multimedia learning, it thus is more efficient to provide children with dyslexia with audio or with auditory support.

Genetic and environmental risk factors for developmental dyslexia in children: systematic review of the last decade

Despite advances in the characterization of developmental dyslexia (DD), several questions regarding the interplay between DD-susceptibility genes and environmental risk factors remain open. This systematic review aimed at answering the following questions: What has been the impact of new resources on the knowledge about DD? Which questions remain open? What is the investigative agenda for the short term? Forty-six studies were analyzed. Despite the growing literature on DD candidate genes, most studies have not been replicated. We found large effects on causative genes and smaller environmental contributions, involving maternal smoking during pregnancy, SES and the DYX1C1-1259C/G marker. Implications are discussed.

Translating dyslexia across species

Direct relationships between induced mutation in the DCDC2 candidate dyslexia susceptibility gene in mice and changes in behavioral measures of visual spatial learning have been reported. We were interested in determining whether performance on a visual-spatial learning and memory task could be translated across species (study 1) and whether children with reading impairment showed a similar impairment to animal models of the disorder (study 2). Study 1 included 37 participants who completed six trials of four different virtual Hebb-Williams maze configurations. A 2 × 4 × 6 mixed factorial repeated measures ANOVA indicated consistency in performance between humans and mice on these tasks, enabling us to translate across species. Study 2 included a total of 91 participants (age range = 8-13 years). Eighteen participants were identified with reading disorder by performance on the Woodcock-Johnson III Tests of Achievement. Participants completed six trials of five separate virtual Hebb-Williams maze configurations. A 2 × 5 × 6 mixed factorial ANCOVA (gender as covariate) indicated that individuals with reading impairment demonstrated impaired visuo-spatial performance on this task. Overall, results from this study suggest that we are able to translate behavioral deficits observed in genetic animal models of dyslexia to humans with reading impairment. Future studies will utilize the virtual environment to further explore the underlying basis for this impairment.

Pay Attention!: Sluggish Multisensory Attentional Shifting as a Core Deficit in Developmental Dyslexia

The aim of this review is to provide a background on the neurocognitive aspects of the reading process and review neuroscientific studies of individuals with developmental dyslexia, which provide evidence for amodal processing deficits. Hari, Renvall, and Tanskanen (2001) propose amodal sluggish attentional shifting (SAS) as a causal factor for temporal processing deficits in dyslexia. Undergirding this theory is the notion that when dyslexics are faced with rapid sequences of stimuli, their automatic attentional systems fail to disengage efficiently, which leads to difficulty when moving from one item to the next (Lallier et al., ). This results in atypical perception of rapid stimulus sequences. Until recently, the SAS theory, particularly the examination of amodal attentional deficits, was studied solely through the use of behavioural measures (Facoetti et al., ; Facoetti, Lorusso, Cattaneo, Galli, & Molteni, ). This paper examines evidence within the literature that provides a basis for further exploration of amodal SAS as an underlying deficit in developmental dyslexia.

Physiologic discrimination of stop consonants relates to phonological skills in pre-readers: a biomarker for subsequent reading ability?(†)

Reading development builds upon the accurate representation of the phonological structure of spoken language. This representation and its neural foundations have been studied extensively with respect to reading due to pervasive performance deficits on basic phonological tasks observed in children with dyslexia. The subcortical auditory system - a site of intersection for sensory and cognitive input - is exquisitely tuned to code fine timing differences between phonemes, and so likely plays a foundational role in the development of phonological processing and, eventually, reading. This temporal coding of speech varies systematically with reading ability in school age children. Little is known, however, about subcortical speech representation in pre-school age children. We measured auditory brainstem responses to the stop consonants [ba] and [ga] in a cohort of 4-year-old children and assessed their phonological skills. In a typical auditory system, brainstem responses to [ba] and [ga] are out of phase (i.e., differ in time) due to formant frequency differences in the consonant-vowel transitions of the stimuli. We found that children who performed worst on the phonological awareness task insufficiently code this difference, revealing a physiologic link between early phonological skills and the neural representation of speech. We discuss this finding in light of existing theories of the role of the auditory system in developmental dyslexia, and argue for a systems-level perspective for understanding the importance of precise temporal coding for learning to read.

Investigating the role of visual and auditory search in reading and developmental dyslexia

It has been suggested that auditory and visual sequential processing deficits contribute to phonological disorders in developmental dyslexia. As an alternative explanation to a phonological deficit as the proximal cause for reading disorders, the visual attention span hypothesis (VA Span) suggests that difficulties in processing visual elements simultaneously lead to dyslexia, regardless of the presence of a phonological disorder. In this study, we assessed whether deficits in processing simultaneously displayed visual or auditory elements is linked to dyslexia associated with a VA Span impairment. Sixteen children with developmental dyslexia and 16 age-matched skilled readers were assessed on visual and auditory search tasks. Participants were asked to detect a target presented simultaneously with 3, 9, or 15 distracters. In the visual modality, target detection was slower in the dyslexic children than in the control group on a “serial” search condition only: the intercepts (but not the slopes) of the search functions were higher in the dyslexic group than in the control group. In the auditory modality, although no group difference was observed, search performance was influenced by the number of distracters in the control group only. Within the dyslexic group, not only poor visual search (high reaction times and intercepts) but also low auditory search performance (d′) strongly correlated with poor irregular word reading accuracy. Moreover, both visual and auditory search performance was associated with the VA Span abilities of dyslexic participants but not with their phonological skills. The present data suggests that some visual mechanisms engaged in “serial” search contribute to reading and orthographic knowledge via VA Span skills regardless of phonological skills. The present results further open the question of the role of auditory simultaneous processing in reading as well as its link with VA Span skills.