The Event-related Potential Study On The Semantic Processing Of The Dyslexic Students

Dyslexia is a common learning disabilities in school-age children. Exploring the mechanism ofdyslexia can help us to identify the dyslexic children and look for the teaching methods. Currently thereare a lot of research in this field from western countries. The results is very rich, but some of the views areinconsistent. The study of Chinese dyslexia didn’t have a very early begining, every aspect of the study wasnot thorough enough and perfect. In order to make differences between dyslexic children and normalchildren in the brain mechanisms of semantic processing stages, we should vigorously strengthen the studyof Chinese dyslexia.In this study, We use the ERP method to research the differences between reading disabilities andnormal students in the semantic processing.The first experiment use the pairs of real Chinese words andpseudo ones as experimental materials, selecting the lexical decision task to record the differences of theresponses time, the correct rate and brain waves between the real and pseudo words. The results asfollowing: reading disabled students and normal ones’ the responses time have significant difference, anddisabled students have the more length of75ms above than normal students; the correct rate does not existsignificant differences; the differences wave shows that there are relatively large differences in the twogroups between250-600ms, the maximum wave peak in400ms. The statistical results confirmed thisphenomenon. This suggests that the brain processing mechanism of the reading difficulties students isdifferent form the normal students in semantic processing tasks.The second experiment used a simple sentence with the matching and mis-matching words in theend. It is cognitive ERP experiment, The simple sentence is composed of two words and a conjunction,presenting in a startup mode. Explore the similarities and differences of the brain mechanism betweenhandicapped children and normal children in this mode. The results show that, The two groups weredifferent in judging the reaction of the simple sentence, there were significant differences on the N400involatility. Another findings are that the difference wave of reading disabled students and normal students isin the200-600ms in matched and mismatched sentence, and in the central frontal area of the brain’ righthemisphere are quite different, which may be caused by the experimental model. Central frontal area of theright hemisphere may play a big role in the beginning and end the overall integration and processing ofstatements environment.