Studies On Family Environment Factors And Brain Imaging Of Phonological Activation With Chinese Dyslexic Children

ObjectiveWe aims to investigate the family environment factors which influence Chinese dyslexic children and reveal Chinese dyslexic children's brain activity features in recognizing Chinese characters, for further understanding the pathogenesis of dyslexia and providing a theoretical basis for prevention, diagnose and intervention.Methods(1) In part 1, six hundred and fifty-four children from two primary schools in Wuhan from Grades three to five and their parents and teachers were selected to finish the questionnaires by cluster random sampling. Screening method was used to find dyslexic children and path analysis was done in the present study.(2) In part 2, thirty-eight children from two primary schools in Wuhan from Grades four to six were divided into two groups: dyslexic group (n=14) and control group (n=24). Stroop paradigm was adopted. And when the two groups completed three different kinds of color-judgment tasks, the behavioral data was recorded. Meanwhile, functional near-infrared spectroscopy was used to observe the hemodynamic changes on prefrontal cortexes of participants.Results(1) The result of path analysis showed"offering resources to encourage children to read","children having difficulty in finishing homework"and"parent-child reading"were inner factors. Furthermore,"education level of parents"and"family economic status"were outer factors. The outer factors affected the occurrence of dyslexia indirectly through the inner factors.(2) When two groups completed three different kinds of color-judgment tasks, their reaction time showed the same trend: the reaction time of color characters in the incongruent condition was the longest, the reaction time of control characters was second, and the reaction time of homophones in the incongruent condition was the shortest. This difference did not reach statistical significance (dyslexic group: F=0.11,P=0.897; control group: F=2.60,P=0.082).(3) The oxyhemoglobin was significantly lower in dyslexic group than that in control group (F=16.42 , P=0.000), while the deoxyhemoglobin was opposite, that is the deoxyhemoglobin was significantly higher in dyslexic group than that in control group (F=9.66,P=0.002). And there was no significant difference in the total hemoglobin between two groups (F=0.57,P=0.449). In addition, the activation of channel 1,2,3,5,7,8,9,10,11,12 in two groups was stronger.Conclusions(1) Both home literacy environment and family socioeconomic status effected the development of reading ability in children by different ways. The home literacy environment produced an effect on children's reading ability more directly, suggesting that creating a good home literacy environment has important practical significance in prevention of dyslexia.(2) In the process of Chinese character recognition, phonological information was activated automatically in both groups. It indicated that the automatic activation of phonological information was necessary in whether the dyslexic group or the control group during Chinese characters recognition.(3) Both the bilateral prefrontal inferior frontal gyrus (BA44/45) and the bilateral dorsolateral prefrontal cortexes (BA9/46) from two groups were involved in processing Chinese characters. However, the active level of the dyslexic group in the prefrontal brain region was lower than that of the control group, suggesting that the brain activation pattern was different between dyslexic children and normal children.