Modular multilevel TMS device with wide output range and ultrabrief pulse capability for sound reduction.

Journal Article (Journal Article)

Objective.This article presents a novel transcranial magnetic stimulation (TMS) pulse generator with a wide range of pulse shape, amplitude, and width.Approach.Based on a modular multilevel TMS (MM-TMS) topology we had proposed previously, we realized the first such device operating at full TMS energy levels. It consists of ten cascaded H-bridge modules, each implemented with insulated-gate bipolar transistors, enabling both novel high-amplitude ultrabrief pulses as well as pulses with conventional amplitude and duration. The MM-TMS device can output pulses including up to 21 voltage levels with a step size of up to 1100 V, allowing relatively flexible generation of various pulse waveforms and sequences. The circuit further allows charging the energy storage capacitor on each of the ten cascaded modules with a conventional TMS power supply.Main results. The MM-TMS device can output peak coil voltages and currents of 11 kV and 10 kA, respectively, enabling suprathreshold ultrabrief pulses (>8.25μs active electric field phase). Further, the MM-TMS device can generate a wide range of near-rectangular monophasic and biphasic pulses, as well as more complex staircase-approximated sinusoidal, polyphasic, and amplitude-modulated pulses. At matched estimated stimulation strength, briefer pulses emit less sound, which could enable quieter TMS. Finally, the MM-TMS device can instantaneously increase or decrease the amplitude from one pulse to the next in discrete steps by adding or removing modules in series, which enables rapid pulse sequences and paired-pulse protocols with variable pulse shapes and amplitudes.Significance.The MM-TMS device allows unprecedented control of the pulse characteristics which could enable novel protocols and quieter pulses.

Full Text

Duke Authors

Cited Authors

  • Zeng, Z; Koponen, LM; Hamdan, R; Li, Z; Goetz, SM; Peterchev, AV

Published Date

  • March 17, 2022

Published In

Volume / Issue

  • 19 / 2

PubMed ID

  • 35189604

Pubmed Central ID

  • PMC9425059

Electronic International Standard Serial Number (EISSN)

  • 1741-2552

Digital Object Identifier (DOI)

  • 10.1088/1741-2552/ac572c


  • eng

Conference Location

  • England