High-Frequency TMS Coil Modulation for Smaller, Lower-Power Stimulation
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Solution Overview
Problem
Current transcranial magnetic stimulation (TMS) technologies are limited to frequencies below 3 kHz due to neuronal response limitations, which restricts the application of higher frequencies that could enhance neuromodulation efficacy and reduce coil size, power consumption, and noise.
Innovation Solution
Employing high-frequency amplitude and frequency modulation techniques to induce a modulated electromagnetic field outside the neuronal response range, utilizing a conductive coil with a modulated HF neurostimulator to generate a time-varying flux density that creates a stimulation electric field within the neuronal stimulable range through envelope detection or constructive interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional low frequency TMS is used, then neurons can respond to stimulation, but coil size and power consumption increase
Solution Approach 1:
The patent changes the operating frequency parameter from conventional low frequency (0-3 kHz) to high frequency (10-100 kHz or higher). This parameter change enables the use of smaller coils while maintaining effective neuronal stimulation, as the high frequency fields produce sufficient electric field strength through rapid flux density changes without requiring large coil dimensions.
Solution Approach 2:
The patent utilizes high frequency electromagnetic oscillations (vibration) to generate the stimulation field. By operating at frequencies of 10-100 kHz or higher, the system creates rapidly changing magnetic flux that induces effective electric fields in neural tissue, enabling smaller coil sizes while maintaining stimulation efficacy.
2Reliability
If conventional low frequency TMS is used, then neurons can respond to stimulation, but power consumption and heat generation increase
Solution Approach 1:
The patent changes the frequency parameter to high frequency operation (10-100 kHz or higher), which reduces the coil current requirements and power consumption. The high frequency fields achieve effective stimulation with lower power input, reducing heat generation in the coils while maintaining neuronal response.
3Reliability
If conventional low frequency TMS is used, then neurons can respond to stimulation, but coil current requirements increase
Solution Approach 1:
The patent changes the operating frequency to high frequency (10-100 kHz or higher), which fundamentally alters the current requirements. At these frequencies, the rapid flux density changes produce sufficient induced electric fields with lower coil currents, reducing power demands while maintaining effective neuronal stimulation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient neuromodulation with reduced coil current and power consumption, smaller coil size, increased focality and penetration depth, and noiseless operation, while allowing flexible control over stimulation parameters.
Implementation Method 1
TMS establishes the electric field in the target region by passing a time varying electric current through a particularly structured and arranged conductive coil... a time-varying magnetic flux density
Implementation Method 2
Employing high-frequency amplitude and frequency modulation techniques to induce a modulated electromagnetic field outside the neuronal response range, utilizing a conductive coil with a modulated HF neurostimulator to generate a time-varying flux density that creates a stimulation electric field within the neuronal stimulable range through envelope detection or constructive interference
Data Source
AI summary
Examples include spatially positioning, in a three-dimensional (3D) space, a conductive coil and a living subject in a 3D spatial relation in which a target 3D region of the living subject's tissue is within a designated 3D electric field formation region for the conductive coil. An energizing source feeds a low frequency (LF) modulated high frequency (HF) carrier voltage to terminals of the conductive coil. This urges a corresponding LF modulated HF coil current, of maximum magnitude MA, through the conductive coil. The HF frequency of the HF coil current produces a magnetic flux with a corresponding HF related rate of change. Optionally, a secondary coil feeds an unmodulated HF signal that spatially overlaps the modulated HF signals.