Study Of Gray Matter And Function In First-onset Pediatric Obsessive-Compulsive Disorder: Association With Clinical Symptoms

BackgroundObsessive-compulsive disorder(OCD)is a common and chronic psychiatric disorder.The main clinical manifestations of OCD are obsessions and(or)compulsions.The symptom onset of one-third of the patients begin in childhood.However,the pathological mechanism of OCD is still unclear.Patients with OCD exhibit markedly disrupted cerebral structural and functional abnormalities in neuroimaging data.Most of the current studies are about adult patients with OCD.However,the research about pediatric OCD is paucity.This study aimed to evaluate the brain structure and function of pediatric OCD using resting-state magnetic resonance imaging,and their correlations with clinical symptoms,and to provide evidence for the mechanism of pediatric OCD.Objectives1.To analyze the characteristics of gray matter volume(GMV)in pediatric OCD.And to analyze the characteristics of amplitude of low-frequency fluctuation(ALFF)and functional connectivity in pediatric OCD under resting state.2.To analyze the above data’s correlations with the clinical symptoms in pediatric OCD.Methods1.Research object: According to the "American Mental Disorders Diagnostic and Statistical Manual,Fourth Edition",36 cases of obsessive-compulsive disorder in children and adolescents who met the inclusion criteria were selected and choosed as the case group.At the same time,we matched 35 healthy controls(HCs)with the case group for gender,age.In the process of data analysis,5 patients in the case group were excluded after structural data preprocessing,and 6 patients were excluded after functional data preprocessing,and 2 healthy subjects were excluded.Therefore,31 patients in the case group were included in the GMV data analysis,and 30 patients were analyzed for ALFF and functional connectivity,and 33 control subjects were included in the study.2.Methods:1)The Yale-Brown Obsessive-Compulsive Scale(Y-BOCS)assessment was used to assess obsessive-compulsive symptoms.2)Measurement and analysis of images: The imaging datas were collected with 3.0T MRI equipment.The GMV data analysis was performed using REST(RS-f MRI Data Analysis Toolkit)and VBM8(voxel-based morphometry)software package on MATLAB(The Math Works,Inc,Natick,Massachusetts)platform.The ALFF data preprocessing was performed with resting state functional magnetic resonance imaging data processing assistant DPARSF(http://rfmri.org/DPARSF)software package,based on REST,running on the MATLAB platform.Then,the brain area with altered ALFF values were selected as seeds,and REST was used for seed-based FC analysis to find the brain areas where were statistically significant connection with seed points.3)Correlation analysis: To calculate the correlation between the gray matter volume values and the Y-BOCS scores in pediatric patients with OCD,as well as the ALFF values and the Y-BOCS scores.Results1.The comparison of gray matter volumes between the OCD group and HCsCompared with HCs,patients with OCD showed decreased GMV in the right hippocampus,right inferior frontal gyrus,and left middle temporal gyrus(t=-4.1734,-4.6364,-3.9332),Alphasim corrected,corrected P<0.05.2.The results of ALFF and functional connectivity between the OCD group and HCs1)ALFF results: Compared with HCs,patients with OCD showed a significant decrease in ALFF predominantly distributed over the left and right putamen(t=-4.2976,-3.848).Alphasim corrected,corrected P<0.05.2)Functional connectivity results: The bilateral putamen,which had altered ALFF values,was selected as the seeds.Compared with HCs,patients with OCD exhibited weakened connectivity of the left putamen with the left caudate,left thalamus,and left paracentral lobule(t=-4.9037,-3.7409,-3.8885).Further,patients with OCD showed decreased connectivity of the right putamen with the right superior frontal gyrus,left superior parietal gyrus,left central posterior gyrus,and right cingulate gyrus(t=-3.9992,-3.2677,-4.1378,-4.4699).Alphasim corrected,corrected P<0.05.3.Relationship between the Y-BOCS scores and GMV values in pediatric patients with OCD,as well as the Y-BOCS scores and ALFF values1)Relationship between the Y-BOCS scores and GMV values in pediatric patients with OCD: Pearson’s and partial correlation analyses showed GMV values of the right hippocampus were negatively correlated with the Y-BOCS total scores,obsession scores,and compulsion scores(r=-0.623,-0.562,-0.452;P<0.05).Similarly,GMV values of the left middle temporal gyrus were negatively correlated with the Y-BOCS total scores and obsession scores(r=-0.395,-0.380;P<0.05).Contrastingly,GMV values of the right inferior frontal gyrus were positively correlated with the compulsion scores(r=0.435;P<0.05).2)Relationship between the ALFF values and the Y-BOCS scores in pediatric patients with OCD: Pearson’s and partial correlation analyses showed the left putamen,which had altered ALFF values,was negatively correlated with the Y-BOCS total scores and obsession scores(r=-0.587,-0.577;P < 0.05).Conclusions1.Pediatric patients with OCD exhibited abnormal structure in the right hippocampus,right inferior frontal gyrus,and left middle temporal gyrus.And pediatric patients with OCD exhibited abnormal function in the cortico-striato-thalamo-cortical circuit,and the parietal lobe.2.Pediatric patients with OCD exhibited altered structure and function in several brain regions.Further,the abnormalities were associated with clinical symptoms.These findings elucidate the abnormalities may be related to the onset of OCD.