New Approach on Generating Electromagnetic Waves for Transcranial Magnetic Stimulation

This paper presents a new method to improve the performance of transcranial magnetic stimulation (TMS) devices. Existing TMS coils are limited in their ability to target desired neural populations due to depth-focality tradeoff and their reliance on high-energy pulse sources, which raises safety concerns. However, the proposed method utilizes the modulated magnetic field of a permanent magnet, which is equivalent to a lossless electromagnet. The magnetic reluctance of the medium surrounding the permanent magnet is modulated to alter magnetic flux intensity and direction, resulting in a time-variant field. The simulation results show that the focality and penetration depth is improved while using significantly less power than conventional TMS devices that use figure-8 coils.