Functional magnetic resonance imaging study on working memory deficiency of children with learning disability

Objective:To research the deficiencies of frontal lobe and parietal lobe of the cerebral cortex during working memory in children with learning disability by functional magnetic resonance imaging(fMRI),explore the mechanism.Methods:12 children with learning disability and 12 normal children were selected,step-by-step visual additive test was used as stimulant mode,blood oxygen level-dependent cerebral function imaging and diffusion tensor imaging were conducted,the differences of active sites and intensities of frontal lobe and parietal lobe of the cerebral cortex,partial anisotropic values of region of interest in white matter in the two groups were compared.Results:The active intensities of bilateral frontal lobe and parietal lobe of the cerebral cortex in learning disability group were weaker than those in control group(P0.05);the partial anisotropic values of left fronto-parietal lobe(0.51±0.05),left frontal lobe(0.61±0.03) and left parietal lobe(0.43±0.04) were significantly lower than those in control group(P0.05);the average level of active pixel number at dorsal region of left frontal lobe in learning disability group was(136.92+3.68),which was correlated with the partial anisotropic value of left fronto-parietal lobe(γ=0.636,P=0.026);the average level of active pixel number at dorsal region of left frontal lobe in control group was(165.75±4.33),which was correlated with the partial anisotropic value of left fronto-parietal lobe(γ=0.822,P=0.001).Conclusion:Active deficiency of frontal lobe and parietal lobe of the cerebral cortex exists in the course of working memory in children with learning disability,which is related to low grade of maturity of white matter,and it may indicate the mechanism of learning disability.