Working Memory Functions And Effects Of Training In Chinese Developmental Dyslexia Children

Dyslexia is a learning85%～90%of the learning disability children was combined or suffering from dyslexia and is disability characterized by difficulties with accurate and/or fluent word recognizing, spelling and decoding abilities despite adequate intelligence, education, and socioeconomic status and is one of the main subtypes of learning disability. The prevalence rate of dyslexia was5%-10%. The Chinese language provides a unique medium for testing this notion, because logographic characters in Chinese are based on meaning rather than phonology. The cognition model of working memory effective links among visual symbols, phonology, and semantics of Chinese characters.The present study orientated on the working memory deficiency theory, and with the aim to study the epidemic characteristies of Chinese dyslexia children and understand the the working memory function of Chinese dyslexia children. The present study indicates that training of working memory may be useful for children with Chinese development dyslexia. The study thus has important practical implication, which means that Chinese development dyslexia may benefit from working memory training.Part1:Epidemiological longitudinal retrospective study on Chinese Dyslexia ChildrenObjective:To study the distribution characteristics in the different years of the epidemic characteristics of Chinese dyslexia childrenMethods:One elementary school was selected representatively according to randomized cluster sampling methods, and totally435children were selected in this investigation. The questionnaires including DCCC (Dyslexia Cheeklist for Chinese Children), PRS (The Pupil Rating Scale Revised Screening for Leaning Disabilities),and Combined Raven's Test. Combined with2003,2005and2009survey data on dyslexia, the Chinese dyslexic children incidence distribution trends were longitudinal retrospective analyzed.Results:The prevalence rate of developmental dyslexia in2003,2005,2009,2011respectively were8.04%,6.30%,7.06%,7.59%. Developmental dyslexia male to female ratio were1.97,2.45,1.47,2.03. There is no difference on the prevalence rate and male to female ratio in difference years (P>0.05)Conclusions:The prevalence rate of developmental dyslexia was high. The incidence was stable between5-10%. Developmental dyslexia gender existed differences.Part2:The working memory function of Chinese dyslexia childrenObjective:To explore the Chinese dyslexic children's working memory function.Methods:33Dyslexic children were chosen according to the International Classification of Diseases-10(ICD-10), the control group included33children matched for gender, age. All subjects were assessed by rhyming paradigm. The Articulatory unrehearsal component task and articulatory rehearsal component task were used to phonological loop function measure and their reaction time (RT), error rate(ER) were analyzed. All subjects were assessed by written vocabulary skills, phonological processing skills and orthographic skills. Visual matrix span task and Corsi span task were used to measure visual-spatial working memory. The color-word stroop task was used to investigate and the central executive function of dyslexic children.Reference to the study of Prabhakaran task, who investigated the characteristics of the buffer function of dyslexic children.Results:No significant difference both RT and error rate ER between dyslexic and normal readers in articulatory unrehearsal component task(P<0.05). The RT and ER of dyslexic children was significantly higher (P<0.05) in articulatory rehearsal component task compared to the normal readers. The RT and ER of the normal readers in articulatory rehearsal component task was significantly lower (P<0.05) than that in articulatory unrehearsal component task. No significant difference on the ER of dyslexic children in the two task (P>0.05). The scores of dyslexic children on language cognition were significantly lower on the normal readers (P<0.05). The scores of dyslexic children on Visual matrix span task scores and Corsi span task were significantly lower on the normal readers(P<0.05). There were significant statistically correlation coefficients between the scores of Visual matrix span task scores and Corsi span task and the scores of written vocabulary skills and orthographic skills. There were no significant statistically correlation coefficients with phonological processing skills (P>0.05). The accuracy in spatial task, verbal task, verbal-spatial bound task, verbal-spatial separate task of children with dyslexic children were lower than that of normal children, the differences were significant (p<0.05). The relation of RT Were RTspatial<RTverbal<RTverbal-spatial bound<RTverbal-spatial separate-Conclusions:Chinese dyslexic children had a deficiency in the working memory function.Part3:Effects of working memory training in Chinese children with developmental dyslexiaObjective:The present study investigated the relationship between working memory and literacy in Chinese children with developmental dyslexia. The aim of the current study was to explored to what extent dyslexic children's working memory could be trained and whether training of working memory would enhance dyslexic children's literacy development.Methods:Thirty dyslexic children used a new working memory training program and evaluated the effect of training with a double blind, placebo controlled design. The treatment group with fifteen dyslexic children and the control group with fifteen dyslexic children were trained in working memory tasks for five weeks.Results:The effect of training in respective group was tested by comparing the outcome score at post-test (Time2; T2) with baseline scores at (Time1; T1).The performance on all of four verbal working memory measures, visual-spatial working memory measure, central executive measure(Time for completion on Stroop task) was improved at T2relative to T1in the treatment group(T1:Corsi span task3.40±1.24,Digit Span forward9.38±2.32,Digit Span backward4.08±1.61,Word span task forward10.00±2.00,Word span task backward3.15±1.41,Time for completion in Stroop105.31±19.73; T2:Corsi span task4.87±0.83,Digit Span forward10.23±1.92,Digit Span backward5.00±1.58,Word span task forward11.23±1.54,Word span task backward4.46±1.61,Time for completion in Stroop91.72±16.30), the differences were significant (P<0.05).The performance on two literacy measures(Accuracy and RT on visual rhyming task, p<0.05, One minute tests of reading words, p<0.01) was also improved at T2relative to T1in the treatment group. Effect sizes were calculated using Cohen's effect size formula.The effect size turned out to be substantial in visual-spatial working memory and two literacy measures:Corsi span task1.39, RT on visual rhyming taskl.13. One minute tests of reading words1.13. The progress on word span backward scores was significantly correlated with progress on accuracy of visual rhyming task (r=0.49). The progress on Corsi span task was significantly correlated with progress on literacy measures (accuracy on visual rhyming task, RT on visual rhyming task, one minute tests of reading words) r were0.56,0.73,0.59. The Time for completion on Stroop task was related to the one minute tests of reading words progress (r=0.72). The differences were significant (p<0.05).Conclusions:The results show that working memory can be seen as a pivotal factor in the reading development among children with developmental dyslexia, and that interventions to improve working memory may help dyslexic children becoming more proficient in reading.