| Objective Pain is the main reason for patients with temporomandibular disorders(TMD)to seek medical treatment.It is unclear whether the cause of this condition is purely peripheral,or also involves problems in the central nervous system.Some studies have shown that patients with TMD pain have abnormal brain structure and these abnormalities related to the psychosomatic status of the patients.However,previous findings have been inconsistent.The purpose of this study was to take advantage of the power of the recently developed machine learning technique(i.e.,multivariate pattern analysis,MVPA)combined with voxel-based morphometry(VBM)method applied to magnetic resonance imaging(MRI)data to investigate the changes of gray matter volume in the brain of patients with TMD pain,and then to explore the relationship between the gray matter volume changes and psychological factors.Methods8 cases of female temporomandibular joint synovitis patients with unilateral open-mouth pain were collected as experimental group and 10 carefully matched healthy persons were collected as the control group.Visual analogue scale(VAS)was used to evaluate the pain intensity of patients and Symptom Check-list 90(SCL-90)were used to assess the mental health status of all subjects.Then we collected structural MRI data from all subjects and compared the gray matter volume(GMV)measured by VBM between the two groups using both univariate(single-voxel analysis)and multivariate(MVPA)analyses.Finally,the correlation analysis was carried out between the average GMV values of identified brain areas and the VAS scores as well as SCL-90 symptom scores within the patient group.Results1.The SCL-90 scores in the patients were significantly higher than healthy controls except for fear and paranoia(p< 0.05).2.The univariate analysis showed that the gray matter volume of the left precuneus,the right inferior temporal gyrus(ITG)and the right middle temporal gyrus(MTG)in the patients was significantly decreased than healthy controls(p<0.001 uncorrected,cluster > 10),and no significant gray matter volume increase was found in patients.3.The MVPA showed that the spatial patterns of gray matter volume in the right secondary somatosensory cortex(S Ⅱ)/inferior parietal lobule(IPL),left precuneus/posterior cingulate gyrus and left inferior/middle temporal gyrus could distinguish patients and healthy controls(p<0.001 uncorrected,cluster >100).4.The correlation analysis showed that the mean GMV value of the cluster in precuneus was negatively related with VAS score and somatization,obsessive compulsive,anxiety,hostility,phobic anxiety score in SCL-90.There was no significant correlation with other SCL-90 symptom factor scores.Besides,the mean GMV values extracted from the cluster in ITG/MTG and SⅡ/IPL were not significantly correlated with VAS score or SCL-90 scores.Conclusion1.Patients with TMD pain are more likely to develop somatization,compulsion,anxiety,depression,hostility and other psychological disorders,which may be related to the development or persistence of pain。2.The univariate and multivariate analysis methods used in this study complementing each other.The univariate analysis showed that the gray matter volume of the left precuneus,the right inferior temporal gyrus(ITG)and the right middle temporal gyrus(MTG)in the patients was significantly decreased than healthy controls.The searchlight MVPA showed that the spatial patterns of gray matter volume in the right secondary somatosensory cortex(S Ⅱ)/inferior parietal lobule(IPL),left precuneus/posterior cingulate gyrus and left inferior/middle temporal gyrus could distinguish patients and healthy controls.3.The changes of precuneus gray matter volume in TMD patients with pain were related with pain score and psychological factors such as somatization,anxiety,pain fear.The interaction between pain and these factors can lead to pain chronification,which may leads to maladaptive plasticity of cerebral cortex. |
PDF Full Text Request