Cognitive Impairment And Bimodal Magnetic Resonance Imaging In Acute Mild Traumatic Brain Injury

Previous studies have indicated that patients with mild traumatic brain injury(m TBI)show neurobehavioural deficits,especially in cognitive behaviors.This impairment is related to the destruction of white matter structure and abnormal functional connectivity(FC)in the brain.However,the neurobiological mechanism of cognitive impairment is still unclear due to the lack of bimodal imaging studies on acute m TBI cognition.The aim of this study is to investigate the relationships between cognitive dificits in acute m TBI patients and structural changes of specific fibers as well as the abnormal FC of their coupled brain regions.In this study,16 m TBI patients and 28 healthy controls(HCs)were enrolled.We used a global test battery including six cognitive domains and an episodic memory task to comprehensively assess cognition.We explored changes of the fractional anisotropy(FA)and mean diffusivity(MD)of 12 association fibers including arcuate fasciculus(AF),uncinate fasciculus(UF),cingulum,superior longitudinal fasciculus(SLF),and lower longitudinal(inferior longitudinal fasciculus(ILF),inferior occipitofrontal fasciculus(IFOF)using diffusion tensor imaging(DTI).Moreover,we inverstigate the abnormal function in fiber-connected brain regions using resting-state functional magnetic resonance imaging(rs-f MRI).Furthermore,the group differences of cognitive function,fiber’s parameters and FC were analyzed using independent two-sample t test,analysis of covariance and Wilcoxon ranksum test.Finally,the relationship between cognitive function and imaging results was explored using partial correlation analysis.Our study found that FA of right arcuate in acute m TBI patients was significantly higher than that in HC,and in m TBI group,and higher FA was accompanied by worse memory function.We also found lower MD of IFOF indicated worse verbal episodic memory.In addition,abnormal FC between lateral occipital cortexand superior parietal lobule,orbital gyrus and middle temporal gyrus in m TBI group were significantly correlated with the memory score and performance in the episodic memory task.These findings indicated fibers like arcuate and IFOF as well as regions like the occipital lobe and parietal lobe also played important roles in verval episodic memory.This study explored the relationships between cognitive function impairment and abnormal structure-function coupling.These findings may provide new neuroimaging evidence for cognitive impairment and shed light on the neurobiological mechanism of cognitive impairment in acute m TBI.