Analysis Of Brain Complex Network Under TDCS Intervention In Stroke Patients

Stroke,with the high incidence and disability,is a serious brain disease that seriously affects the normal work and life of patients and their families.Transcranial direct current stimulation(t DCS)as a new way for the treatment of the stroke has many characteristics such as high safety,low cost and easy operation.However,its action mechanism and therapeutic effect are not clear.As the effective method to research the mechanism of stroke disease,EEG signal analysis has the advantages of non-destructive and non-invasive.In this paper,t DCS was used as an intervention method for stroke diseases.The before,during and after EEG signals were collected to research the changes.The effects of t DCS on stroke diseases were investigated from three aspects: power spectral density analysis,brain functional network analysis and brain effective connectivity analysis.The main contents of this paper include:1.The changes of EEG power spectral density in the C3 lead of the left hemisphere patients and the C4 lead of the right hemisphere patients with the eyes closed and open were analyzed.The results indicated that the power spectral density of the alpha band after t DCS stimulation in the C3 lead and C4 lead was improved,and the alpha band amplitude of the eyes closed was larger than the eyes open,which illustrated that t DCS can enhance the alpha band amplitude,and the effect of the eyes closed was better than the eyes open when t DCS was conducted.2.The partial directed coherence was adopted for the EEG data with left and right hemisphere patients to construct the brain functional networks.The six network parameters,such as in-degree,out-degree,characteristic path lengths,clustering coefficient,betweenness centrality,network efficiency,were calculated and statistically analyzed.The small-world property of brain functional networks were judged.The results indicated that t DCS has a significant influence on other network parameters except out-degree.Compared with before stimulation,the small-world property of the network after stimulation was enhanced,and the network information transmission efficiency was increased.3.The directed transfer function method was adopted to establish and analyze the effective connectivity models for left and right hemisphere patients in the alpha band.The results indicated that compared with before stimulation,the number and intensity of left and right hemisphere patients effective connectivity after stimulation were increased,which mainly manifested in the increases between the frontal lobe,central region of the affected hemisphere and the healthy hemisphere.It showed that t DCS can enhance the effective connectivity between the affected hemisphere and the healthy hemisphere in stroke patients.Compared with before stimulation,the information transmission after stimulation was increased.The results provided the theoretical and experimental basis for analyzing the effects of t DCS on stroke diseases.