Design Analysis and Circuit Topology Optimization for Programmable Magnetic Neurostimulator

Area of Science:

• Neuroscience
• Biomedical Engineering
• Electrical Engineering

Background:

• Transcranial magnetic stimulation (TMS) is a key non-invasive brain stimulation technique.
• Optimizing TMS pulse characteristics is crucial for effective neuromodulation but remains a technical challenge.
• Existing TMS systems have limitations in generating flexible and precisely shaped magnetic pulses.

Purpose of the Study:

• To introduce a second-generation programmable TMS (xTMS) device with advanced stimulus shaping capabilities.
• To demonstrate the generation of highly adjustable magnetic pulses with control over waveform, polarity, and pattern.
• To present a modular and scalable design for arbitrary magnetic pulse generation.

Main Methods:

• Utilized cascaded H-bridge inverters and phase-shifted pulse-width modulation (PWM) for pulse generation.
• Employed a low-pass RC filter model to estimate neural behavior and guide magnetic pulse generator design.
• Experimental measurements of monophasic, biphasic, and polyphasic waveforms were performed.

Main Results:

• The xTMS device successfully generated highly adjustable magnetic pulses.
• Peak coil currents reached up to 6 kA, with delivered energy up to 250 J.
• Demonstrated the capability to produce various complex pulse waveforms.

Conclusions:

• The developed xTMS equipment provides a flexible solution for generating customizable magnetic pulses.
• The modular and scalable design facilitates arbitrary pulse shaping for advanced neuromodulation.
• This technology has the potential to enhance repetitive TMS paradigms and research.