Meta-Analysis of Fluid Intelligence Tests of Children from the Chinese Mainland with Learning Difficulties

OBJECTIVE To evaluate the differences in fluid intelligence tests between normal children and children with learning difficulties in China. METHOD PubMed, MD Consult, and other Chinese Journal Database were searched from their establishment to November 2012. After finding comparative studies of Raven measurements of normal children and children with learning difficulties, full Intelligent Quotation (FIQ) values and the original values of the sub-measurement were extracted. The corresponding effect model was selected based on the results of heterogeneity and parallel sub-group analysis was performed. RESULTS Twelve documents were included in the meta-analysis, and the studies were all performed in mainland of China. Among these, two studies were performed at child health clinics, the other ten sites were schools and control children were schoolmates or classmates. FIQ was evaluated using a random effects model. WMD was -13.18 (95% CI: -16.50- -9.85). Children with learning difficulties showed significantly lower FIQ scores than controls (P<0.00001); Type of learning difficulty and gender differences were evaluated using a fixed-effects model (I² = 0%). The sites and purposes of the studies evaluated here were taken into account, but the reasons of heterogeneity could not be eliminated; The sum IQ of all the subgroups showed considerable heterogeneity (I² = 76.5%). The sub-measurement score of document A showed moderate heterogeneity among all documents, and AB, B, and E showed considerable heterogeneity, which was used in a random effect model. Individuals with learning difficulties showed heterogeneity as well. There was a moderate delay in the first three items (-0.5 to -0.9), and a much more pronounced delay in the latter three items (-1.4 to -1.6). CONCLUSION In the Chinese mainland, the level of fluid intelligence of children with learning difficulties was lower than that of normal children. Delayed development in sub-items of C, D, and E was more obvious.