Emotion Dysregulation Following Traumatic Brain Injury:A Multimodal Mri Study

?Background?Emotion dysregulation is the core feature of a series complications with emotional disorder following traumatic brain injury(TBI).Although the emotion dysregulation is not a diagnosis,it has been reported as the core characteristic of many mental disorders caused by brain injury,for example personality change,post-traumatic stress disorder,bipolar disorder,depression and so on.As known to us,TBI have the high disability and fatality rate in modern society,and nearly 10 million people are affected by its sequelae every year in worldwide.Moreover,TBI is an increasingly common cause of behavioral and emotional dysregulation among hospitalized patients.However,the neural mechanism of emotion dysregulation following TBI is still unclear.It is generally assumed that the alteration of brain structure is the root of emotion dysregulation.Specifically,brain injury leads to abnormal brain structure and function,which affects the process of emotion regulation and causes symptoms of emotional dysregulation.Since little research about the neural mechanism of emotion dysregulation following TBI is reported,there were no targeted therapy and drugs in the clinical treatment,which seriously affects the patient's daily life and work.In forensic psychiatry assessment,there is of great difficulty in identifying the emotional disorders following TBI,especially when the extent of structural injury does not match the degree of dysfunction.Thus,how to comprehensively analyze the alteration of brain structural and function in forensic identification is of great important.?Aims?In the present study,we aimed at investigating the neuroimaging presentation of emotion dysregulation following TBI by multimodal MRI system,and analyze the pathogenesis of emotion dysregulation.?Methods?To study pathogenesis of emotion dysregulation,we recruited patients with personality changes following TBI,whose symptom was featured as emotion dysregulation.Therefore,the subjects of current study mainly consisted of TBI group with emotion dysregulation and health control group with normal emotion regulation.In addition,all subjects were assessed on the emotional traits by using emotion rating scales,such as the Emotion Regulation Difficulty Scale(DERS),the Emotional Responsiveness Scale(ERS),the Emotional Intelligence Scale(EIS),and the Eysenck Personality Scale.The neuroimaging data of all subjects in current study were acquired from the same 3-T Philips(Ingenia CX)MRI system.The modalities applied in our study mainly include: structural MRI(s MRI),Diffussion Tensor Imaging(DTI),resting-state f MRI,task-state f MRI.The analysis methods for different modalities data in current study were: voxel-based morphology analysis,voxel-based analysis,brain activation and functional connectivity analysis,brain activation and psychophysiological interaction analysis.In addition,the algorithm of multimodal upport vector machine(SVM)was used to construct the classification model by fusing the s MRI,DTI,and resting-state f MRI data in current study.?Results?After the comprehensively analysis of multimodal MRI data,we found that patient with emotion dysregulation showed significant alterations of brain structure and function.1.Specifically,based on the s MRI modality data,we found that the gray matter volume of left paracentral lobule significantly increased,while the left thalamus,parahippocampal gyrus,right straight gyrus,and inferior temporal gyrus were significantly decreased in the emotion dysregulation group.While the white matter volume of the bilateral cingulate gyrus,the left medial prefrontal lobe and parietal lobe were significantly increased in the emotion dysregulation group.2.Based on the DTI modality data,we found that the structural integrity of white matter fiber were impaired in some brain regions,including the left frontal parietal cortex,the right middle temporal gyrus and bilateral cingulate gyrus.3.Based on resting-state f MRI data,we found that the regional homogeneity values of the right insula,and the amplititude of low-frequency fluctuation values of the bilateral anterior central gyrus and middle frontal gyrus in patients with emotion dysregulation were significantly increased.The functional connectivity between the right insula and left cingulate gyrus,left middle frontal gyrus and temporal lobe,and cingulate gyrus were decreased in emotion dysregulation group.4.Based on task-state f MRI data,we found that patients with emotion dysregulation cannot successfully regulate their emotion by using cognitive reappraisal strategy.Specifically,the brain activation of the dorsal thalamus and the functional connectivity with the frontal-parietal lobe were enhanced during down-regulate negative emotion condition.5.The multimodal SVM study revealed that the classification model had the best effect only when fusing the s MRI,DTI,and resting-state f MRI simultaneously.Among them,the weight of resting-state f MRI was 0.6,while the weights of s MRI and DTI were 0.3 and 0.1,respectively.?Conclusions?1.At the level of brain structure,there were significant alterations in the gray matter volume and structural integrity in some brain areas of patients with emotional dysregulation following traumatic brain injury.The alteration may be the structural basis of emotional dysregulation.Thus,attention should be paid to these brain regions in clinical treatment and forensic assessment.2.At the level of brain function,we found that the emotion regulation and response related brain regions were hyperactivation,while the functional connectivity were decreased,which gave rise to emotion regulation dysfunction in resting state.In the cognitive reappraisal task,the right thalamus was hyperactivation,and the functional connectivity with frontoparietal lobe were enhanced,which may increase the burden of emotion regulation related brain regions.3.The result of multimodal SVM study suggested that both brain structure and function should take into consideration in forensic psychiatry assessment.Moreover,compared to the alteration of brain structure,the brain functional abnormalities were more useful in forensic assessment.