Tdcs Inter-Individual Variability In Electric Field Distribution For Chronic Stroke: A Simulation Study

Transcranial Direct Current Stimulation is a non-invasive brain stimulation that modulates brain activity and enhances post-stroke recovery. However, TDCS effects are highly variable, which might be caused by the difference in individual electric fields. We constructed individualized volume conductor models and performed electric field simulations TDCS for 24 stroke subjects. Correlation analysis was performed to identify associations between electric field and lesion properties. Significant correlations were observed between the field strength and lesion-anode distance (r=-0.61,p=0.003) and lesion-target distance(r=-0.59, p=0.005). Subsequent analysis found that distance between the stimulation hotspot and target was positively correlated with lesion-hotspot distance (r= 0.58,p=0.004) and anode-hotspot distance (r=0.94, 0.000). Our results shows possible tunneling effects induced from stroke lesions which increases the stimulation intensity to its nearby volumes. With heterogeneous lesion properties for stroke individuals, more efforts are required to design an optimal stimulation montage for chronic stroke.