Study On The Social Adaptation And Executive Function Of Chinese Children With Down Syndrome

Down syndrome (DS) is one of the most common genetic diseases with mental retardation. DS has characteristic cognitive impairment phenotype because of its unique genotype. Over expression of DS critical region leads to changes associated with brain anatomy and function. A special cognitive profile can be observed in DS patients of white races. Their social adjustments are much better than their verbal mental development; what's more, they have an uneven pattern of executive function. While there are complex dose-effect relationship between genes and phenotype, more study is needed to further the research of DS. No reports on the study of social adjustment and executive function of DS children could be found in our country up to now. The goal of this study was to provide an objective assessment of their development of social adjustment and several components of executive functions including attention, inhibition, working memory and task management. The Infants-Junior Middle School Students' Social-Life Abilities Scales, attention testsoftware, WALK test, digit span and Wilding monster sorting test were used to investigate the social adjustment and executive function of DS children and the normal controls.Chapter I Social adjustmentSection I Study on the social adjustment of children with Down syndromeMethods Peabody Picture Vocabulary Test (PPVT) and the Infants-Junior MiddleSchool Students' Social-Life Abilities Scales were conducted within DS children, normally-developing children matched for mental age (MA) and normally-developing children matched for chronological age (CA). Verbal mental age, social adjustment was evaluated in the three groups, as well as the relationship between social adjustment and PPVT raw score or age.Results There was no difference between the DS group and the MA group in terms of communication skills(P>0.05). However, the DS group scored much higher than the MA group in self-help, locomotion, occupation, socialization and self-direction (P<0.05 ) . Children in the CA group achieved significantly higher scores in all domains of social adjustment than the DS group ( P<0.05 ) . Educated DS children had better social adjustment than their uneducated peers ( P<0.05 ) . A correlationship was found between development of social adjustment and chronological age/verbal mental age in DS children(P<0.05 ) .Chapter II Executive functionSection I Study on the attention of children with Down syndromeMethods PPVT and visual research tests were conducted to evaluate the selective,switching and sustained attention among the DS children and the normal children. Verbal mental age and selective attention, switching attention, sustained attention were all evaluated between the two groups.Results DS group performed better than the MA controls in selective attention witha simple background(P<0.05), they had less error response of background and higher accurate rate. They was significantly worse than the controls in a complex background with more distractors which had similar shape to target stimulation(P<0.05). No difference was found in the overall performance of the two groups in the test of switching attention except error responses of shape(P<0.05). As to the number of error responses and overall distance, MA controls had better performance than DS group(P<0.05), but not others in sustained attention task.Section II Study on the inhibition of children with Down syndromeMethods PPVT and WALK test were conducted between the DS group and MAgroup.Verbal mental age and inhibition were evaluated between the two groups, as well as the relation between attention and inhibition.Results There were no difference was found between the DS group and MAgroup(P>0.05). After controlling effects of PPVT raw score, scores of WALK test were associated with error response of sustained attention in DS group (P<0.05).Section III Study on the working memory of children with Down syndrome.Methods PPVT and digit span were conducted between the DS group and MAgroup. Verbal mental age, phonological loop and central executive function were all evaluated in the two groups, as well as the relationship between working memory and inhibition.Results There was no difference between the DS group and MA group inbackward digit span(P>0.05). However, DS children showed a much worse performance in forward digit span than controls(P<0.05). Partial correlations indicated a relationship between WALK test score and backward digit span after controlling the effects of PPVT raw score in controls (P<0.05)but not in DS children(P>0.05).Section IV Study on the task management of Chinese children with Down syndromeMethods PPVT and Wilding monster sorting task (WMST) were conducted between the DS group and the MA group. Verbal mental age and task managing ability were evaluated.Results There was no difference between the performance of DS group and MAcontrols(P>0.05).Conclusion(1) The social adjustment development of DS children is better than their verbal mental age with uneven pattern. Comunication of DS children is worse than other domain. DS children can achieve better social adjustment under special education. Social adjustment is correlated with chronological age and verbal mental age.(2) Development of the general selective attention parallels with the development of verbal mental age in DS children, while visual perception and shape discrimination are underdeveloping the verbal mental age. No difference is found in switching attention except error response of shape. DS children have worse performance in terms of sustained attention. Compare to verbal mental age, there is an uneven pattern of the development of attention.(3) An earlier onset of development of cortex inhibition than vocabulary ability in DS children may be detected. A correlation is found between inhibition and sustained attention in DS children.(4) Compare to phonological loop, central executive has been preserved in DS children, which means there is a different development of phonological loop and central executive. A correlation is found between inhibition and sustained attention in typically developing children but not DS children.(5) No difference of task management between DS children and MA controls. Further study is needed.