An Efficient Noninvasive Neuromodulation Modality for Overactive Bladder Using Time Interfering Current Method

Objective: The present study aimed to evaluate a new tibial nerve stimulation (TNS) modality, which uses interferential currents, in terms of the stimulation electric field penetration efficiency into the body and physiological effectiveness. Methods: In silico experiments were performed to analyze the penetration efficiency of proposed interferential current therapy (ICT). Based on this, we performed in vivo experiments to measure excitation threshold of ICT for the tibial nerve, which is related to stimulation field near the nerve. Regarding analysis of the physiological effectiveness, in vivo ICT-TNS was performed, and changes in bladder contraction frequency and voiding volume were measured. The penetration efficiency and physiological effectiveness of ICT were evaluated by comparison with those of conventional TNS using transcutaneous electrical nerve stimulation (TENS). Results: Simulation results showed that ICT has high penetration efficiency, thereby generating stronger field than TENS. These results are consistent with the in vivo results that nerve excitation threshold of ICT is lower than that of TENS. Moreover, ICT-TNS decreased contraction frequency and increased voiding volume, and its performance was profound compared with that of TENS-TNS. Conclusion: The proposed ICT is more efficient in inducing the stimulation field near the tibial nerve placed deep inside the body compared with conventional TENS and shows a good clinical effectiveness for TNS. Significance: The high efficiency of ICT increases the safety of noninvasive neurostimulation; therefore, it has clinical potential to become a promising modality for TNS to treat OAB and other peripheral neurostimulations.