A Study on the Multi-Channel TMS Device

Transcranial magnetic stimulation (TMS) is a painless, non-invasive brain nerve stimulation technique, which has been a common diagnosis and treatment method for psychiatry and neurology in recent years. Compared with traditional single-channel magnetic stimulation coil, multi-channel coil array can achieve multi-point synchronous stimulation, scanning stimulation, and flexible switching of various stimulation patterns. Therefore, it has a great development prospect. However, the multi-channel TMS device is still in experimental stage due to the complexity of the drive circuit and the electromagnetic coupling between the coils. Aiming at these two difficulties, this paper developed a novel multi-channel TMS device. By using two closely linked coils with opposite rounded direction to replace one coil, the complexity of the drive circuit can be greatly reduced. Then, the experiment was taken to study the effect of electromagnetic coupling on pulse current in different stimulation patterns. The results show that the coupling coefficient between the adjacent coils limits the minimum amplitude ratio of the auxiliary current to main current. Therefore, the measure of reducing the coupling coefficient was studied in detail. Adding a 6.5 cm-high and 1 mm-thick copper plate in the middle of the adjacent coils was proven to be effective by simulation and experiment.