Multi-coil Transcranial Magnetic Stimulation Array
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Solution Overview
Problem
Current transcranial magnetic stimulation (TMS) technologies face challenges in delivering focused electric fields deep into the brain, as the electric field becomes diffuse and decays rapidly with distance from the coil, leading to unwanted stimulation of large tissue regions near the brain surface.
Innovation Solution
A multi-channel coil array design is introduced, where coils are electrically connected in series and driven by a single current source, with each coil dimensioned to stimulate brain tissue at a specific distance while minimizing the volume of excited tissue, using a computer-assisted method involving genetic algorithms to optimize coil configurations for targeted neuronal stimulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single coil is used to generate magnetic fields for TMS, then the apparatus is simple in structure, but the electric field becomes diffuse and decays rapidly with distance, stimulating large regions of tissue near the surface
Solution Approach 1:
The patent divides a single coil into multiple smaller coils arranged in an array configuration. Each coil can be independently controlled to generate magnetic fields that collectively target deeper brain regions while maintaining spatial precision. This segmentation allows the system to overcome the rapid decay and diffusion problems of single-coil designs.
Solution Approach 2:
The patent transitions from a single-coil design to a multi-coil array, adding spatial dimensionality to the system. By arranging coils in specific geometric patterns and controlling their individual contributions, the system achieves three-dimensional field shaping capability, enabling precise targeting of deep brain structures without excessive surface stimulation.
2Ease of operation
If coils are positioned closer to the scalp for easier operation, then the apparatus is easier to operate, but the electric field decays rapidly with distance and stimulates large tissue volumes
Solution Approach 1:
By segmenting the stimulation field into multiple coil contributions, the system can position coils closer to the scalp for ease of operation while using individual coil control to limit the volume of excited tissue. Each coil targets a specific sub-region, and their combined effect achieves deep penetration without excessive surface stimulation.
Solution Approach 2:
The patent implements local quality control by allowing each coil in the array to be independently controlled with specific current amplitudes and phases. This enables the system to create localized high-field regions at deep targets while maintaining low field strength at superficial locations, effectively decoupling coil placement convenience from stimulated tissue volume.
3Length of stationary object
If multiple coils are used to target deeper regions, then the penetration depth is improved, but the device complexity increases with multiple coils and control channels
Solution Approach 1:
The patent merges multiple coil functions into a unified array system where coils are closely spaced and controlled in coordination. By treating the array as an integrated system rather than separate components, the design achieves deep penetration capability while managing complexity through shared control architecture and optimized spatial arrangement.
Solution Approach 2:
The multi-coil array design provides multi-functionality, enabling the same apparatus to target multiple different brain regions by adjusting individual coil contributions. This universal design allows a single device to perform various stimulation tasks at different depths and locations, justifying the increased complexity through enhanced versatility and deep targeting capability.
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
The multi-channel coil array design effectively minimizes the volume of brain tissue stimulated, allowing for more precise and deeper penetration of magnetic fields, achieving better targeting and reduced unwanted stimulation compared to single-channel designs.
Implementation Method 1
the current source injects time varying current into the coils to create a magnetic field
Implementation Method 2
generate magnetic fields inside the head that in turn induce electric fields and eddy-currents inside conductive brain tissue
Implementation Method 3
induce electric fields and eddy-currents inside conductive brain tissue
Data Source
AI summary
An improved apparatus is provided for transcranial magnetic stimulation in a brain of a subject. The apparatus is comprised of: a plurality of coils electrically connected in series to each other; and a single source of current electrically coupled to one of the plurality of coils. Each coil may include one or more windings of similar dimensions although the size of the windings varies between coils. Each of the coils is further dimensioned to stimulate brain tissue at a given distance while minimizing volume of the brain tissue excited by the magnetic field. During operation, the current source injects time varying current into the coils to create a magnetic field which in turn induces electric fields and eddy-currents inside the brain tissue of the subject.