Auditory, Visual, and Cross-Modal Temporal Processing Skills Among Chinese Children With Developmental Dyslexia

Impaired Ability in Visual-Spatial Attention in Chinese Children With Developmental Dyslexia

A growing body of evidence suggests that children with dyslexia in alphabetic languages exhibit visual-spatial attention deficits that can obstruct reading acquisition by impairing their phonological decoding skills. However, it remains an open question whether these visual-spatial attention deficits are present in children with dyslexia in non-alphabetic languages. Chinese, with its logographic writing system, offers a unique opportunity to explore this question. The presence of visual-spatial attention deficits in Chinese children with dyslexia remains insufficiently investigated. Therefore, this study aimed to explore whether such deficits exist, employing a visual search paradigm. Three visual search tasks were conducted, encompassing two singleton feature search tasks and a serial conjunction search task. The results indicated that Chinese children with dyslexia performed as well as chronological age-matched control children in color search tasks but less effectively in orientation search, suggesting a difficulty in the rapid visual processing of orientation: a deficit potentially specific to Chinese dyslexia. Crucially, Chinese children with dyslexia also exhibited lower accuracy, longer reaction times, and steeper slopes in the reaction times by set size function in the conjunction search task compared to control children, which is indicative of a visual-spatial attention deficit.

How Does Visual Temporal Processing Affect Chinese Character Reading in Children With Dyslexia? From the Perspective of Inhibition

Given that inhibition interacts with visual temporal processing (VTP), the past evidence regarding the influence of VTP on the Chinese character reading of children with dyslexia may not disclose the whole picture without considering inhibition. Thus, the present study is among the first to investigate VTP and cognitive inhibition as well as their relationships to Chinese character reading. We compared the performances of 62 Chinese-speaking children with dyslexia in primary school (n = 62, Mage = 11.36 years) on VTP and inhibition tasks to those in a chronological-age-matched group (CA; n = 62, Mage = 11.57 years) and reading-level-matched group (RL; n = 62, Mage = 8.98 years). The results revealed that children with dyslexia performed worse than both the CA-matched and RL-matched groups in VTP and inhibition after controlling for age, nonverbal intelligence, and attention. Moreover, the relationship between VTP and Chinese character reading was moderated by inhibition in children with dyslexia. VTP is positively related to Chinese character reading, but this relationship is observed only at higher levels of inhibition. Our results suggest that inhibition plays a potential role in VTP and Chinese character reading, especially for those with dyslexia whose proficiency in inhibition is not as intact as that of typically developing children.

Audiovisual multisensory integration in individuals with reading and language impairments: A systematic review and meta-analysis

Differences in sensory function have been documented for a number of neurodevelopmental conditions, including reading and language impairments. Prior studies have measured audiovisual multisensory integration (i.e., the ability to combine inputs from the auditory and visual modalities) in these populations. The present study sought to systematically review and quantitatively synthesize the extant literature on audiovisual multisensory integration in individuals with reading and language impairments. A comprehensive search strategy yielded 56 reports, of which 38 were used to extract 109 group difference and 68 correlational effect sizes. There was an overall difference between individuals with reading and language impairments and comparisons on audiovisual integration. There was a nonsignificant trend towards moderation according to sample type (i.e., reading versus language) and publication/small study bias for this model. Overall, there was a small but non-significant correlation between metrics of audiovisual integration and reading or language ability; this model was not moderated by sample or study characteristics, nor was there evidence of publication/small study bias. Limitations and future directions for primary and meta-analytic research are discussed.

Reduced audiovisual temporal sensitivity in Chinese children with dyslexia

Background

Temporal processing deficits regarding audiovisual cross-modal stimuli could affect children's speed and accuracy of decoding.

Aim

To investigate the characteristics of audiovisual temporal sensitivity (ATS) in Chinese children, with and without developmental dyslexia and its impact on reading ability.

Methods

The audiovisual simultaneity judgment and temporal order judgment tasks were performed to investigate the ATS of 106 Chinese children (53 with dyslexia) aged 8 to 12 and 37 adults without a history of dyslexia. The predictive effect of children's audiovisual time binding window on their reading ability and the effects of extra cognitive processing in the temporal order judgment task on participants' ATS were also investigated.

Outcomes and results

With increasing inter-stimulus intervals, the percentage of synchronous responses in adults declined more rapidly than in children. Adults and typically developing children had significantly narrower time binding windows than children with dyslexia. The size of visual stimuli preceding auditory stimuli time binding window had a marginally significant predictive effect on children's reading fluency. Compared with the simultaneity judgment task, the extra cognitive processing of the temporal order judgment task affected children's ATS.

Conclusion and implications

The ATS of 8-12-year-old Chinese children is immature. Chinese children with dyslexia have lower ATS than their peers.

Is orthographic knowledge a strength or a weakness in individuals with dyslexia? Evidence from a meta-analysis

The purpose of this meta-analysis was to examine if individuals with dyslexia (DYS) have a deficit in orthographic knowledge. We reviewed a total of 68 studies published between January 1990 and December 2019, representing a total of 7215 participants. There were 80 independent samples in the chronological-age (CA)-DYS comparison and 33 independent samples in the comparison between DYS and reading-level (RL) controls. A random-effects model analysis revealed a large effect size (Cohen's d = 1.17) for the CA-DYS comparison and a small effect size (Cohen's d = 0.18) for the RL-DYS comparison. In addition, we found significant heterogeneity in the effect sizes that was partly explained by the level of orthographic knowledge (effect sizes being higher for lexical than sub-lexical orthographic knowledge). These results suggest that individuals with dyslexia experience an orthographic knowledge deficit that is as large as that of phonological awareness and rapid automatized naming reported in previous meta-analyses.