Repetitive transcranial magnetic stimulator with controllable pulse parameters (cTMS)

Area of Science:

• Neuroscience
• Biomedical Engineering
• Electrical Engineering

Background:

• Transcranial Magnetic Stimulation (TMS) is a non-invasive neuromodulation technique.
• Conventional TMS devices have limitations in pulse parameter control, energy efficiency, and heat generation.
• Optimizing TMS parameters is crucial for enhancing therapeutic efficacy and exploring new applications.

Purpose of the Study:

• To introduce a novel controllable-pulse-parameter TMS (cTMS) device.
• To evaluate the energy efficiency and coil heating characteristics of the cTMS device compared to conventional TMS.
• To demonstrate the capability of the cTMS device for high-frequency repetitive TMS (rTMS) protocols.

Main Methods:

• The cTMS device utilizes a circuit topology with two energy-storage capacitors and two insulated-gate bipolar transistors (IGBTs).
• The device generates near-rectangular electric field (E-field) pulses with adjustable parameters: number, polarity, duration, and amplitude.
• Pulse phase widths can be set between 5-200 µs, with a positive/negative phase amplitude ratio of 1-10.

Main Results:

• cTMS reduces energy dissipation by 78-82% (vs. monophasic) and 55-57% (vs. biphasic).
• Coil heating is decreased by 15-33% (vs. monophasic) and 31-41% (vs. biphasic).
• Demonstrated stable rTMS trains (up to 50 Hz, 3,000 pulses) with minimal E-field pulse variability (<1.7% amplitude, <1% width).

Conclusions:

• The cTMS device offers significant improvements in energy efficiency and thermal management.
• Flexible pulse parameter control enhances existing TMS paradigms and opens avenues for novel research.
• The cTMS technology holds potential for enhanced potency in future clinical applications.