Search

This study investigated the impact of Chinese dyslexia subtypes on English literacy skills (i.e., reading fluency and dictation) in Hong Kong children. Eighty-four Cantonese-speaking children officially diagnosed with dyslexia (M[subscript age] = 103 months) and 48 age-matched typically developing (TD) children were tested. Cluster analysis with performances on Chinese syllable awareness (CSA), Chinese phonemic awareness (CPA), Chinese phonological memory (CPM), Chinese orthographic awareness (COA), and matrix reasoning (MR) yielded three cognitive subtypes: the phonological deficit (PD) subtype, the orthographic deficit (OD) subtype, and the global deficit (GD) subtype. After controlling for English language experience, age, and gender, all three dyslexia subtype groups performed significantly worse in English word reading fluency and dictation than the TD children. In addition, the PD group performed worse in English PA; the OD group performed worse in English OA; and the GD group performed worse in all English skills except English PM. We compared the level of impairment in literacy between languages and dyslexia subtypes. In word reading fluency, all subtype groups experienced less impairment in English than Chinese, while the OD group showed the largest English advantage. In dictation, only the OD group showed a significant language effect favoring English. The findings suggest that different subtypes of Chinese dyslexia bear different risks for difficulties in English literacy.

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.

In recent years, iron has been regarded as a common pathological feature of many neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD) and Friedreich's ataxia (FRDA). A number of genes involved in iron transport, storage and regulation have been found associated with initiation and progression of neurodegeneration. However, whether iron abnormalities represent a primary or secondary event still remains unknown. Due to the limitation in transgenic rodent model construction and transfection systems, the progress in unraveling the pathogenic role of different iron-related proteins in neurodegenerative diseases has been slow. Drosophila melanogaster, a simple organism which has a shorter lifespan and smaller genome with many conserved genes, and captures many features of human nervous system and neurodegeneration, may help speed up the progress. The characteristics that spatial- and temporal-specific transgenic Drosophila can be easily constructed and raised in large quantity with phenotype easily determined turn Drosophila into an excellent in vivo genetic system for screening iron-related modifiers in different neurodegenerative conditions and hence provide a better picture about the pathogenic contribution of different iron-related protein abnormalities. It is believed that identification of important iron-related genes that can largely stop or even reverse degenerative process in Drosophila models may lead to development of novel therapeutic strategies against neurodegenerative diseases.