A Resting-state FMRI Study Of Default Mode Network In Mild Traumatic Brain Injury Patients With Transient Memory Disorders

Objective: Mild traumatic brain injury(mTBI) patients often show the transient memory impairment, clinical rehabilitation, judicial authentication and other fields' attention to it is increasing. The follow up revealed that mTBI patients might involve autobiographical memory impairment, while default mode network(DMN) was the key to extract the autobiographical memory. By studying the differences of DMN in resting state between the transient memory disorders mild traumatic brain injury(TMD-mTBI) patients and no transient memory disorders mild traumatic brain injury(NTMD-mTBI) patients, explore the possible mechanism of mTBI with TMD.Methods: Collecting TMD-mTBI patients(18 cases), NTMD-mTBI patients(15 cases) within 7 days after injury and healthy controls(NC)(33 cases), the three groups were examined by resting state fMRI on Siemens Trio Tim 3.0T. The data preprocessing was performed by Data Processing Assistant for Resting State fMRI(DPARSF), used the GIFT software to carry on the independent component analysis(ICA) and extracted the component of DMN by using the maximum space template matching method, one-way ANOVA and post-hoc were used to analyze all experimental data. Finally, linear correlations were performed between the data and the scores of clinical scales.Results: Relative to the NC, the bilateral posterior cingulate cortex(PCC) activity was reduced and the left middle temporal gyrus(MTG) activity was increased in TMD-mTBI group(Voxel p<0.01, Cluster p<0.05, GRF correction), while the right side of PCC activity was increased in NTMD-mTBI group(Voxel p<0.01, Cluster p<0.05, GRF correction), and there was no obvious correlation between the different brain regions' function connection strength values and the scores of clinical scales.Conclusion: There was significant difference in the brain resting state DMN function connection between TMD-mTBI patients and NTMD-mTBI patients, the reduced activity in PCC suggested it was difficult for autobiographical memory retrieval, while the increased activity in PCC suggested there was compensatory activity in some brain regions about memory retrieval of the patients, to make up the abnormal memory activities caused by brain injury. The above results showed that further research in this area might provide novel neurological biomarkers and prognosis assessment tools for TMD-mTBI patients.