A Simulation Study on the Effect of Phase-shift of Temporal Interference Stimulation

In recent years, stimulation of deep areas by temporal interference (TI) electric fields has attracted much attention. Previous studies have shown the feasibility of stimulating targeted deep areas mouse brain and nerve bundles for stimulation. However, the possibility to change stimulus focus without changing the electrode layout has not been investigated.In this study, we investigated whether the phase-shift of the TI could be a control parameter for the location of stimulus focus, using a 3D model with 2/3 muscle electrical property.The potential distribution was measured for different phase-shifting cases. The activating function was calculated and compared to confirm the presence or absence of local focuses.As a result, it was observed that sites with significant activating function change with a phase shift. Though all the sites appeared near electrodes, i.e., there were no such sites in the deeper part of the model away from the electrodes. This research is a fundamental step towards effective selective deep nerves from the skin surface.