Controllable pulse parameter transcranial magnetic stimulator with enhanced pulse shaping

Abstract

Commercially available transcranial magnetic stimulation (TMS) devices provide very limited control over the pulse parameters. We present a third generation controllable pulse parameter device (cTMS3) that uses a novel full-bridge circuit topology with two energy storage capacitors and incorporates a number of implementation and functionality advantages over conventional TMS devices and previous cTMS devices. cTMS3 is implemented with transistors with lower voltage rating than previous cTMS devices. It provides more flexible pulse shaping since the circuit topology allows four coil voltage levels during a pulse, including zero voltage. The zero coil voltage level enables snubbing of the ringing at the end of the pulse without the need for a separate active snubber circuit. cTMS3 can generate powerful rapid pulse bursts (<; 10 ms inter pulse interval) by increasing the width of each subsequent pulse and utilizing the large capacitor energy storage. These features enhance the advantages of cTMS and could extend the utility of TMS as a research, diagnostic, and therapeutic tool.