Study On The Regional Homogeneity In First-episode Major Depressive Disorder With Somatic Pain

Background:The incidence of major depressive disorde is high in China,and it is a kind of mental disease characterized by persistent emotional depression.In addition to the common core symptoms,it is accompanied by non-specific physical symptoms,such as pain,dizziness,chest distress and so on.MDD with somatic pain is very common in clinic.Pain symptoms can cover up the emotional symptoms of patients with depression,delay diagnosis and treatment,aggravate the functional damage of patients,and increase the risk of suicide.In recent years,the rapid development of resting-state functional magnetic resonance imaging（rfMRI）technology,voxel based analysis methods,such as Regional Homogeneity（ReHo）,can well reflect the time synchronization of regional oxygen level dependent signals.At present,there are few reports about the functional abnormality of brain area in depression accompanied with somatic pain.Therefore,using ReHo method to study the brain activity of rfMRI in patients with depression accompanied by somatic pain is helpful to find its biomarkers and serve the clinical.Objectives:Using resting state fMRI,we compared the brain dysfunction between depressive patients and healthy controls by using ReHo method,At the same time,we divided depression patients with pain into groups,and explored the relationship between depression with and without somatic pain.Witch is helpful to explore the neuroimaging mechanism of somatic pain symptoms of depression.Methods:From January 2,2017 to September 30,2018,the subjects were the patients with the first episode of major depressive disorder from the ward or outpatient clinic of Affiliated Hospital of Guangzhou Medical University.These patients have never before received psychiatric related medication or non medication.According to the structured clinical interview of Diagnostic and Statistical Manual of Psychiatric Disorders-Ⅳ（DSM-Ⅳ）,two psychiatrists determined that the patient was diagnosed with depression.A total of 32 eligible patients were enrolled.Hamilton Depression Scale,Hamilton Anxiety Scale,Yang manic rating scale and brief pain recording scale were used to evaluate the clinical performance of the patients in the group,16 of whom had somatic pain.The healthy control group came from the local community,the gender,age and education years were matched with the patients group,a total of33.The head scan was performed in a standard coil using a Philips 3.0T MRI scanner.The obtained MRI images were preprocessed to calculate the ReHo values of all voxels in the whole brain.Through the comparative analysis of the whole brain ReHo values of the depression group with somatic pain and the group without,then the regional clusters with statistical differences were obtained.The correlation between ReHo and age,gender,education years,HAMD-17 total score,BPI average pain score was analyzed by Spearman correlation analysis.Results:There was no significant difference in age,gender and education years between all subjects（p>0.05）.And there was no significant difference in the total score of HAMD-17 between depressive patients with or without somatic pain（p>0.05）.In the depression group,ReHo in the left fusiform gyrus（t=-5.26）,left lingual gyrus（t=-3.80）,left postcentral gyrus（t=-4.89）,bilateral cuneiform lobe（t_l=-3.73,t_r=-3.68）and bilateral peritalar cortex（t_l=-3.97,t_r=-4.28）decreased significantly（p<0.05）,but there was no significant increase in ReHo.Compared with 16 depressive patients with somatic pain and 16 depressive patients without somatic pain,we found that the ReHo of left postcentral gyrus and left precentral gyrus in depressive patients with somatic pain was significantly higher than that without somatic pain(t_postcentrall=4.93,p_postcentrall<0.05;t_precentrall=4.57,pprecentral＿l<0.05).Spearman correlation analysis showed that the mean pain score（mBPI）of depressive patients with somatic pain was positively correlated with the ReHo values of left postcentral and precentral gyrus(r_postcentrall=0.511,p_postcentrall<0.001;rprecentral＿l=0.466,pprecentral＿l<0.001).Conclusions:Our results indicate that the abnormal signals of fMRI in the left fusiform gyrus,left lingual gyrus,left posterior central gyrus,bilateral cuneiform lobes and bilateral peritalar cortex may play a role in the sensory,emotional and cognitive symptoms of depression.The abnormal signals of resting fMRI in the left posterior and left anterior central gyri（sensorimotor area）may be of great value in identifying the symptoms of somatic pain symptoms in depressive patients.