Magnetic stimulation with arbitrary waveform shapes

Abstract

Device technology for magnetic stimulation is still extremely limited regarding waveform dynamics and flexibility. Existing systems are well-known to be very inefficient from an energy perspective. In addition, neither a noninvasive analysis of different neuron dynamics nor an adjustment of the pulse waveform for a more specific stimulation is possible with existing equipment as a matter of principle. The uncontrollable high power in the Megawatt range obstructs such aims with classical means. This contribution introduces a novel stimulator technology which gives up the traditions from classical pulse-source topologies. The design forgoes any high-voltage devices in the actual pulse circuitry, but is based on mass-produced high-power lowvoltage components instead. It enables the generation of almost arbitrary waveforms, including all classical waveforms in magnetic stimulation, with a single device. For any of these pulses the field energy, except the unavoidable basic ohmic losses, can be retrieved from the stimulation coil and be fed back into the internal energy storages. This also applies to classical monophasic pulses, which converted all their energy into heat in classical systems. The power requirements of this technology are comparably low accordingly. The combination of switching control and big highly flexible energy storages moreover enables even high pulse trains as in theta-burst protocols with one pulse source. © 2013 Springer-Verlag.