| Objective:This study is based on the brain network research method of graph theory,the normal control group compared with postconcussion syndrome without tinnitus and postconcussion syndrome with tinnitus,changes of brain network degree and properties in the diencephalon region,reflect the functional connectivity of each brain region(FC),to explore the significance of the changes of brain network properties in patients with concussion syndrome with tinnitus,and to explore the mechanism of tinnitus in such patients.Methods:34 patients with postconcussion syndrome(PCS)were selected,there were 17 patients with bilateral tinnitus(PCS with tinnitus group)and 17 patients without tinnitus(no tinnitus group).In the same period,17 patients were recruited as healthy controls(control group),the age and gender matched with their educational background.Among the groups,the functional magnetic resonance imaging(f MRI)was used to test the blood oxygenation level dependence(BOLD).Collect the original DICOM format data in the resting state,convert data into NIFTI format data for SPM software,the other use the normalize function of SPM software to check the head of the tester,remove the error data of x,y and z in three directions,which are larger than 1.5mm and the rotation degree is greater than 1.5 degrees in three directions,after processing the generated body element,the image is projected into the Talairach space to project the magnetic resonance image into the standard brain map,the gaussian smoothing function deals with the image smoothly,reduce the noise such as heartbeat and breathing,the whole brain covariate,white matter,head movement and cerebrospinal fluid extraneous signal were excluded.Anatomical Automatic Labeling(AAL)is used to divide the brain into90 brain regions,the average of the time series corresponding to the body element in each brain region was obtained,the correlation coefficient of Pearson correlation(PCC)was calculated,Fisher r to z gets the z matrix to diaplay the normal distribution of data.The setting of Sparsity(value range of 0.05 ~ 0.40,with 0.01 as step length)is the threshold,eliminate the useless connection,and Gradually build your brain network.Data processing toolbox BCT(brain connectivity toolbox)obtained the degree and property of the threshold of the brain region,calculate the mean value of each node degree and property,the mean value of each node degree and property is tested by two independent samples,the brain of the node with the difference was obtained.Images with the Brain Net Viewer tool have different nodes.The variation of the degree and property of brain region was analyzed,and functional characteristics of related brain regions,to explore the significance of the changes of brain network properties of PCS with tinnitus patients.Results:(1)The degree attribute values of PCS patients without tinnitus at left orbital middle frontal gyrus(3.13±1.07),left thalamus(2.51±1.03),left superior temporal gyrus(3.67±1.31),right anterior cingulate cortex(3.13±1.25),right posterior cingulate cortex(2.13±1.08)and right supramarginal gyrus(4.46±1.35)reduced,compared with the control group(4.41±1.47,3.71±1.08,5.27±2.13,5.51±0.67,5.63±2.16 and 5.64±1.30)(P<0.05).(2)The degree attribute values of PCS patients without tinnitus at left posterior cingulate cortex(5.87±1.06)and left gyrus lingualis(4.67±1.48)increased,compared with the control group(4.41±1.46 and 3.21±1.27)(P<0.05).The degree attribute values of PCS patients with tinnitus at left posterior cingulate cortex(3.37±1.54),left parahippocampal gyrus(3.41±1.62),left amygdala(2.25±1.43),left angular gyrus(4.17±1.02),left superior temporal gyrus(3.25±1.02),right thalamus(2.35±1.34),right Heschl gyri(3.97±1.62),right superior temporal gyrus(3.26±1.22),right cuneus(3.18±1.32)and right lingular lobe(3.26±1.42)decreased,compared with the control group(4.41±1.46,5.27±2.13,3.71±1.08,5.63±2.61,5.64±1.30,3.43±1.33,5.63±2.16,5.13±1.64,5.51±0.67 and 4.24±0.63)(P<0.05).The degree attribute values of PCS patients with tinnitus at right posterior cingulate cortex(5.76±1.83),left MPFC(6.08±1.62)and right precuneus(6.08±1.06)increased,compared with the control group(4.47±1.26,4.41±1.47 and 4.81±0.62)(P<0.05).(3)The degree attribute values of PCS patients with tinnitus at left MPFC,left amygdale,left parahippocampal gyrus,right Heschl gyri,right superior temporal gyrus,right cuneus and right lingular lobe reduced,compared with PCS patients without tinnitus(P<0.05).The degree attribute values of PCS patients with tinnitus at right posterior cingulate cortex and left insular lobe increased,compared with PCS patients without tinnitus(P<0.05).Conclusion: 1.The functional area of the change of the degree and property belongs to the subnetwork respectively.(1)auditory system(superior temporal gyrus,transverse temporal gyrus).(2)Edge system(buckled back,seahorse back,island leaf,amygdala,frontal gyrus).(3)Default network(medial prefrontal,posterior cingulate,wedge anterior,angular gyrus.(4)Visual system(tongue,wedge).Thalamus is an important pathway in sensory conduction,listed separately.2.The occurrence of tinnitus in patients with concussion is associated with head trauma,traumatic brain dysfunction is an important factor in the occurrence of tinnitus,the long-term existence of shock memories,the repeated occurrence of adverse emotions is the inducing factor.3.postconcussion syndrome with tinnitus is a combination of multiple systems,although there was no physical injury in such patients,functional connections in various brain regions had changed.The change in degree and properties reflects this change objectively,the study of degree and properties can preliminarily explain the mechanism of tinnitus in these patients.4.Different functional systems have different effects on the presence of tinnitus in patients with PCS,the normal signal transmission of auditory vision attenuated,resulting in attenuation of the inhibitory effect on tinnitus signal,the limbic system and the default network system may be the origin of the subjective tinnitus abnormal signal,among of the extraction of tinnitus memory and the repetition of bad emotions,lead to vicious cycle and gradually aggravate the tinnitus symptom.5.The plasticity changes of brain function is the basis for the long-term existence of tinnitus,short-term tinnitus can be gradually eliminated with the recovery of brain function,but with brain plasticity changes to form new functional connections,tinnitus will be present in patients with PCS. |
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