Voxel Morphology Combined With Functional Connectivity To Investigate The Efficacy And Imaging Mechanism Of Transcranial Direct Current Stimulation In Patients With Post-stroke Aphasia

Objective: Transcranial direct current stimulation(t DCS)has been shown in numerous trials to improve behavior and neurological function in the treatment of post-stroke aphasia.Although the improvement of t DCS at the level of behavioral assessment is generally acknowledged,its mechanism at the level of neuroimaging remains unknown.The aim of the study is to explore the mechanism of the curative impact and imaging level of repeated t DCS on post-stroke aphasia.Methods: A double-blind randomized controlled study on 26 right-handed patients with aphasia after subacute ischemic stroke was conducted using High-Definition transcranial Direct Current Stimulation(HD-t DCS).Patients with posterior aphasia were randomly assigned to either anodal transcranial direct current stimulation of the left Broca’s region or sham stimulation,as well as speech training.Each therapy lasted20 minutes and was given 5 times a week for 4 weeks.The Western Aphasia Battery(WAB)was used to evaluate the improvement of patients’ spontaneous speech,listening comprehension,repetition,writing and naming,and the Philadelphia Naming Test(PNT)and Boston Naming Test(BNT)were used to evaluate the progress of patients’ spontaneous speech and naming.Resting-state magnetic resonance scans to explore imaging mechanisms.Results: This study enrolled 26 patients with post-stroke aphasia,and 6 of them dropped out due to discharge during the study.At the behavioral level,there were significant changes in listening comprehension,repetition,naming,and writing in the WAB scale before and after anodal HD-t DCS treatment(P<0.05).In terms of imaging,based on the analysis of the patient’s image structure and function images based on voxel morphology and functional connectivity,the right frontal lobe has a strong correlation with early speech function,which is mainly reflected in the thickening of the middle frontal gyrus and precentral gyrus of the right frontal lobe after treatment compared with pre-intervention GMV,in the correlation analysis of the speech scale,the change value of the right middle frontal gyrus was positively correlated with listening comprehension and repetition(r>0,P<0.05).The increase of ALFF in the right Cerebellum Crus1 was positively correlated with the naming score in the scale(r>0,P<0.05);the decrease of ALFF in the right cerebellum 6 was negatively correlated with the listening comprehension in the scale(r<0,P<0.05).Conclusion: Giving anodal HD-t DCS stimulation in Broca’s area can effectively improve the repetition and naming ability of subacute stroke patients with aphasia.In addition,HD-t DCS may have some efficacy in promoting cerebral neural remodeling after ischemic stroke,thereby improving speech function.