The Effect And Neuroimaging Mechanisms Of Transcranial Direct Current Stimulation On The Somatization Symptom Of Anxiety Disorder

Background Somatization that involves multiple systems is a major feature of anxiety disorder.Somatization increase the complexity and difficulty of treatment of anxiety disorder,lead to repeated outpatient visits by patients,causing serious family and social burden.Therefore,to explore a new way of treatment is necessary.Transcranial Direct Current Stimulation（tDCS）is a non-invasive neuromodulation method.Previously,the dorsolateral prefrontal cortex was the main target of tDCS for anxiety disorder,but the therapeutic effect was not idea.This study attempted to explore a new tDCS target in somatic anxiety disorder.ObjectiveThis study attempted to use high-definition transcranial direct current stimulation（HD-tDCS）to treat patients with somatization anxiety disorder and observe its efficacy.The effects of high-precision direct current stimulation on the function of brain were investigated by using resting state f MRI.Materials and methods18 participants with somatization anxiety disorder were enrolled,and 14 times of anodic HD-tDCS were administered to stimulate the dorsomedial prefrontal cortex with an electric current intensity of 2mA,each treatment lasted 20 minutes.Hamilton Anxiety Scale（HAMA）and Patient Health Questionnaire-15（PHQ-15）were conducted before and after treatment,and the differences before and after HD-tDCS were statistically analyzed to observe the effect of treatment.Functional magnetic resonance scans were performed before and after HD-tDCS.Low-frequency oscillation amplitude（ALFF）,fractional low-frequency fluctuation amplitude（fALFF）,regional consistency（Re Ho）,degree centrality（DC）and functional connection（FC）were calculated before and after HD-tDCS.To explore the correlation between imaging changes and clinical symptom changes,the differences ofALFF,fALFF,Re Ho,DC and FC before and after HD-TDCS HD-tDCS were respectively correlated with the differences of HAMA and PHQ-15 before and after HD-tDCS.ResultsSomatization symptoms and anxiety were significantly improved after HD-TDCS treatment（t =9.694,P<0.05;t =7.417,P<0.05）.fALFF in left lingual gyrus was significantly higher after HD-tDCS than before（t =5.46,P<0.05）;DC in left lingual gyrus（t =4.42,P<0.05）and right calcarine（t =5.56,P<0.05）were significantly higher after HD-tDCS than before;DC in left inferior frontal gyrus was significantly higher after HD-tDCS than before（t =9.30,P<0.05）.FC in left lingual gyrus-right lingual gyrus（t =5.92,P<0.05）,right calcarine-left postcentral gyrus（t =6.06,P<0.05）,and right calcarine-right lingual gyrus（t =5.96,P<0.05）were significantly higher after HD-tDCS than before;FC in left inferior frontal gyrus-left superior parietal gyrus（t =5.43,P<0.05）,left inferior frontal gyrus-right superior parietal gyrus（t =5.09,P<0.05）were significantly lower after HD-tDCS than before;FC in the left lingual gyrus-right calcarine（t =5.47,P<0.05）was significantly higher after HD-tDCS than before.Correlation analysis results: The difference of FC in left lingual gyrus-right lingual gyrus（r =-0.635,P < 0.05）was negatively correlated with the difference of PHQ-15 score.The difference of FC in left lingual gyrus-right calcarine（r=-0.604,P<0.05）was negatively correlated with the difference of PHQ-15 score.The difference of FC in right calcarine-the left postcentral gyrus/FC before HD-tDCS negatively correlated with the difference of HAMA /HAMA score before HD-tDCS（ρ=-0.598,P<0.05）.ConclusionAnodal HD-tDCS（dorsomedial prefrontal cortex,2mA,20 min,14 sessions）could be an effective therapeutic method to improve somatization symptoms and anxiety in patients with somatic anxiety disorder.The enhancement of FC in the left lingual gyrusright lingual gyrus and left lingual gyrus-right calcarine after HD-tDCS may be the neuro imaging mechanism for the improvement of somatization symptoms.The enhancement of FC in the right calcarine-left postcentral gyrus may be the neuro imaging mechanism for the improvement of anxiety symptoms.