A Study On The Phonological Access Of Chinese Children With Developmental Dyslexia In Word Recognition

The difficulty of word recognition is not only the main manifestation of people with developmental dyslexia but also the core problem influencing reading processing.As ideographic characters,the corresponding rules of grapheme and phoneme of Chinese characters are not obvious,and the phonetic information at the word level is not significant.The existing researches pay more attention to the sequence of the activation time of grapheme,phoneme,and semantic when recognizing Chinese characters,but the online processing process of grapheme and phoneme access has not been effectively explored.Therefore,in this study,the eventrelated potential(ERP)technology was used to explore the process of graphemephoneme access of the children with developmental dyslexia from grades 4 to 5 when recognizing individual characters with different word types.In this study,26 developmental dyslexia(DD)children from grades 4 to 5 of a primary school were selected as the experimental group,and 26 typical developing(TD)children who matched the age and intelligence as the control group.Then the children were asked to perform word judgment tasks in response to the stimuli of four types of word conditions(words-W,pseudohomophones-PH1,pseudohomophones-PH2,and pseudowords-PW).Task 1 investigated thegrapheme-semantic access process,and taking W/PH1 as the experimental material,the participants were asked to judge whether the stimulus word looked true or not;Task 2 investigated the processing process of phoneme-semantic access,and taking PH2/PW as the experimental material,the participants were requested to judge whether the stimulus word sounded true or not based on the pronunciation.The experimental results indicated that the developmental dyslexia children in grades 4 and 5 had the disorder of grapheme-phoneme access,which was reflected in the slower response time of the phoneme-semantic pathway than that of the grapheme-semantic pathway,and their brain wave amplitude was significantly smaller than that of the typically developing children.Based on the behavioral data results,it could be known that the accuracy and response time of the DD group were worse than those of the TD group,and there was certain backwardness in literacy.The accuracy of word class from low to high was PH2<PH1<W<PW,and the response time from short to long was W<PW <PH1< PH2.According to the EEG data,N2 amplitude of the TD group under the condition of PH2 was the largest,while there was no significant difference in the DD group under the condition of four types of words.By comparing the EEG data under the condition of PH1 with that of PH2,it was found that the amplitude of P1 component under the condition of PH1 was significantly greater than that under the condition of PH2,and that of N2 component under the condition of PH2 was significantly greater than that under the condition of PH1.In the time window of 135-195 ms after the stimulus,the amplitude of the graphemesemantic pathway was significantly greater than that of the phoneme-semantic pathway,and the amplitude of the TD group was significantly greater than that of the DD group,so the grapheme information played a major role.In the time window of215-275 ms after the stimulus,the amplitude of the phoneme-semantic pathway in the TD group was larger than that of the grapheme-semantic pathway,and the phoneme information played a major role,but there was no significant difference in the DD group,indicating that the DD children could not make good use of the phoneme information in the word recognition.In the word recognition process,the online processing process of the DD and TD children in grades 4 and 5 was similar,showing high activation of occipital,occipito-temporal,and temporal lobes.Grapheme processing was significantly faster than phoneme processing,which was in line with dual-route model,so the grapheme-semantic pathway and the phoneme-semantic pathway existed in the same time.The grapheme-phoneme access disorder of the developmental dyslexia children from grades 4 to 5 was correlated with phonological awareness deficits.The most important problem existing in the grapheme-phoneme access disorder was inefficient sublexical phoneme representation,which resulted in the weak representation of the mental lexicon.Meanwhile,there was no significant difference between grapheme recognition and typically developing children at the sublexical level,but the phonetic information recognition was significantly difficult,and the use of the corresponding rules of grapheme-phoneme was inefficient,which affected the process of single word recognition.Therefore,this study suggested that there is grapheme-phoneme access disorder in the developmental dyslexia.At the same time,there is inadequate phonetic representation of sublexical in the process of single word recognition,which leads to the difficulty in word recognition.