Study On Mental Character And FMRI Of Working Memory Of Children With Learning Disabilities

Objectives1.To explore the epidemic characteristics and risk factors of children with learning disability (LD).2.To study psychological characteristics of children with learning disability.3. To explore the brain mechanism of cognition of children with LD by using functional magnetic resonance imaging (fMRI).Methods1.Epidemic research The samples were obtained by cluster-sampling from grade 3 to 6 in 2 primary schools of Wuhan.2. Screening and diagnosis of LD The screening of children with LD were conducted by using Pupil Rating Scale Revised Screening for Learning Disability(PRS),and combined with Chinese Classification ofMentalDisease(CCMD-2),intelligencelevel,academicachievement ,and got rid of visual-acoustic disorder, hyperactivity and organic disease, the LD was diagnosed.3. Evaluation of psychological characteristics The intelligence level, personality and quality of life were evaluated by using Combined Raven's Test(CRT),Eysenck Personality Questionnaire(EPQ) and Subjective Quality of Life(SQOL),respectively.4. fMRI test MRI superconductivity machine (Singa l.5T CV/i) produced by American GE Corporation was used to test the brain acting status when the children executed the working-memory tasks. And the procedure of working memory waswork out according to blocked-design and event-related design .Results1. Research on epidemiological character and influence factors of children with LDNine hundred and forty seven children were studied, and the effective samples were 907 by rejecting incomplete samples( effective rate was 95.35 %.).(1) The prevalence of LD was 9.97% (males were 11.69%, females were 7.86%), and there was no significant difference between male students and female students(x2=3.66, P>0.05).(2) The prevalence of behavior problem of learning disability children was 28.89%, and obviously higher than that of normal children (19.31%) (x2=4.60, P<0.05). The prevalence of behavior problem of normal children had significant difference in sex(males were 15.53%,females were 23.73%, respectively, x2=8.74, P<0.01), but that of LD children were no difference in sex(males were 27.59%,females were 31.52%, respectively, x2=0.134, P>0.05).(3) Multi-factors logistic analysis indicated that age was protective factors of male students of LD(OR=1.293 , 95%CI were 0.958～1.747) , while lower parents'culture degree, single parent family, inconsistent parents'teaching patterns and have hyperactivity were risk factors of male students with LD(OR value were 0.609,0.237,0.258,0.963,respectively). Only child was protective factors of female students with LD(OR=0.282,95%CI were 0.125～0.632) , while inconsistent parents'teaching patterns and have violation of discipline were risk factors of female students with LD(OR value were 0.248,0.657, respectively).2. Case-control study on mental characters of children with learning disabilityNinety children with LD were diagnosed (male: 60, female: 30), and certain normal children with middling academic records were selected as control group according to 1:1 in the same class, age (±3 month) and sex.(1) The intelligence level of learning disability children (IQ: 92.67±11.65) was obviously lower than that of normal group (IQ: 108.28±11.95). The ratio of IQ which above middle intelligence level among LD children account of 65.5%,and was less than the control group(95.6%) obviously(X2=9.21 , P<0.01) .It showed that learning disability children's visual integration, organization ability, as well as the vision structural capacity and abstract thinking ability had deficiencies.(2) The standard scores of subscales of N and P of EPQ in children with Learning disability (P:55.39±8.25,N:52.11±12.83) were higher than that of normal children (P: 52.72±8.18,N:48.06±12.45) significantly (P<0.01 and 0.05,respectively). It hinted that learning disability children had high spiritual nature and unstable personality characteristic.(3) Except the partner communication and physical feeling, the scores of other factors and total scores of SQOL in children with LD were lower than that of control group significantly(P<0.05). It indicated that the quality of life of children with learning disability was worse than that of normal children.3. fMRI study on working memory of children with learning disabilities With agreement of the subjects, 12 learning disability children and same-amount normal children were selected respectively as the case and control group to implement the fMRI on working memory, and all of the children were right handedness and had normal intelligence (IQ>85) and vision, and the children's families didn't have epilepsy or other nervous system diseases.(1) The comparison of two groups of children in active brain regions and intensity indicated that the same active brain regions were mainly located on two-side lobus frontal cortex and the near regions of anterior central gyrus, next was the lobus parietal cortex and lobus occipital cortex.(2) Active intensity of control group was higher than the LD group in the regions of left superior frontal gyrus and right midfrontal gyrus (P <0.05), but there was no significant difference in lobus parietal cortex and lobus occipital cortex. The results indicated that learning disability children had some deficiency in the process of temporary memory, such as coding, storing, extracting, and repeating et al, and was also related possibly with the attention dysfunction or maintenance disorder. It hinted that frontal cortex had hypoplasia or functional dysfunction probably.Conclusions1. The above results showed that the prevalence of LD is 9.97% (male is 11.69%, female is 7.86%), which was consistent with the domestic reports. Children with learning disability had more behavioral problems. The family factor (parents'education, family type, parents'education attitude and so on) and the child behavioral problems (poly-motion, violation of regulations) had some certain forecasting function for the occurrence and the development of learning disabilities. The results showed that various influence factors of LD were intercommunication and interaction. It was very difficult to eliminate the interference of other factors. How to analysis the etiological factor of LD in the multistrata, aspect and overall level will deserve to study further.2. The intelligence level of learning disability children was obviously lower than normal group's. The ratio of IQ, which above middle intelligence level among LD children, was less than the control group obviously. It showed that learning disability children's visual integration, organization ability, as well as the vision structural capacity and abstract thinking ability had deficiencies.3. Learning disability children had high spiritual nature and unstable personality characteristic. And their quality of life was worse than that of normal children.4. fMRI research indicated the active intensity of LD group was weaker than the normal group in the regions of left superior frontal gyrus and right midfrontal gyrus. It hinted that frontal cortex had hypoplasia or functional dysfunction probably. And fMRI study of working memory of LD children would provide important basis for researching on this aspect.New IdeasThe research was a part of National Natural Science Foundation of China (No.30271132). Combined with epidemic investigation and clinic research, the cause, psychological characteristic and brain mechanism of LD were studied, and the new ideas as follows:1.This research involved in many domains, such as psychology, behavioral science, medicine, and so on.2.This research involved in risk factors, psychological characteristics and neuro-physiological mechanism of children with LD.3.The research methods and instruments were new, and fMRI test was first applied to study the activity of brain of LD children while executing working memory tasks in China.