Working-memory training improves developmental dyslexia in Chinese children

Although plasticity in the neural system underlies working memory, and working memory can be improved by training, there is thus far no evidence that children with developmental dyslexia can benefit from working-memory training. In the present study, thirty dyslexic children aged 8-11 years were recruited from an elementary school in Wuhan, China. They received working-memory training including training in visuospatial memory, verbal memory, and central executive tasks. The difficulty of the tasks was adjusted based on the performance of each subject, and the training sessions lasted 40 minutes per day, for 5 weeks. The results showed that working-memory training significantly enhanced performance on the nontrained working memory tasks such as the visuospatial, the verbal domains, and central executive tasks in children with developmental dyslexia. More importantly, the visual rhyming task and reading fluency task were also significantly improved by training. Progress on working memory measures was related to changes in reading skills. These experimental findings indicate that working memory is a pivotal factor in reading development among children with developmental dyslexia, and interventions to improve working memory may help dyslexic children to become more proficient in reading.

Priming effects in Chinese character recognition for Chinese children with developmental dyslexia

BACKGROUND： Dyslexic children exhibit reading ability unmatched to age, although they possess normal intelligence and are well educated. OBJECTIVE： To examine the performance of dyslexic children in Chinese characters visual recognition tasks and to investigate the relationship between priming effect in character recognition and dyslexia. DESIGN, TIME AND SETTING： A case-control study was performed at the Department of Children and Adolescent Health and Maternal Care, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology between March and June 2007. PARTICIPANTS： A total of 75 primary school students in grades 3 and 5 were selected from two primary schools in Wuhan City, Hubei province, China, and were assigned to three groups. （1） Reading disability （RD, n = 25）; （2） chronological age （CA） group （n = 25 normal readers that were intelligence quotient and age-matched to the RD group）; （3） reading level （RL） group （n = 25 normal readers that were intelligence quotient and RL-matched to the RD group）. All children were right-handed and had normal or corrected-to-normal vision. METHODS： Recognition of target characters was performed in each child using a masked prime paradigm. Recognition speed and accuracy of graphic, phonological, and semantic characters were examined. Simultaneously, data, with respect to response time for each target character and error rate, were recorded to calculate facilitation values （unrelated RT-related RT）. MAIN OUTCOME MEASURES： Response time, facilitation, and error rate in Chinese character recognition task were calculated. RESULTS： The baseline-adjusted facilitation of graphic, phonological, and semantic priming for dyslexic children was -0.010, -0.010, and 0.001, respectively. Dyslexic children displayed inhibition in graphic and phonological prime conditions. Facilitations under the three prime conditions were 0.026, 0.026, and 0.022 for the CA group. In the RL group, results were 0.062, 0.058, and 0.031 respectively. The differences of baseline-adjusted facilitation across the three groups were significant [F （2, 216） = 17.91, P 〈 0.01 ], whereas the main effect of prime condition IF （2, 216） = 0.49, P 〉 0.05] and the interaction of group x prime condition [F （4, 216） = 0.91, P 〉 0.05] were not significant. The error rate under the three prime conditions was 0.066, 0.077, and 0.079 for the RD group. As for the CA group, the results were 0.057, 0.071, and 0.074 accordingly, and in the RL group, the results were 0.119, 0.111, and 0.121, respectively. The difference of error rate across the three groups was significant （F = 6.61, P = 0.002）. The error rate was significantly greater in the RL group, compared with the CA and RD groups, while no significant difference existed between the RD and CA groups. CONCLUSION： Dyslexic children were slower to recognize target characters than normal readers, and did not exhibit significant prime effects in graphic and phonological primer condition. These results suggested that dyslexic children exhibited general deficits in phonological and graphic processing, and presented a different pattern in character recognition. These results could be interpreted by parallel-distributed processing models.