Segmented Deep TMS Coil Design for Targeted Brain Stimulation
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Solution Overview
Problem
Current transcranial magnetic stimulation (TMS) coils have limited efficacy in stimulating deep brain regions due to high decay of magnetic and electric fields with distance, leading to minimal effect on deeper neuronal structures and increased risk of seizures and tissue damage when intensity is increased for deeper stimulation.
Innovation Solution
Design of deep TMS coils with a base portion that conforms to the head and includes individually distributed or grouped elements carrying current in a main direction, with return elements on either side to minimize non-tangential components of the electric field, optimizing depth penetration and absolute field intensity for specific brain regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the intensity of the induced field is greatly increased to stimulate deeper neuronal structures, then the efficacy of affecting deeper brain regions is improved, but the risk for seizures and physiological damage to tissue increases
Solution Approach 1:
The coil is divided into multiple discrete current-carrying elements distributed around the periphery of the base, rather than using a single concentrated winding. This segmentation allows the magnetic field to be distributed more evenly across the target area, reducing peak field intensity at any single location while maintaining overall stimulation efficacy for deep brain regions.
Solution Approach 2:
Different regions of the coil have different current densities and orientations optimized for their specific locations on the scalp. The elements are arranged to create locally optimized magnetic field distributions that target specific deep brain structures while minimizing field intensity in superficial regions, thereby reducing the risk of seizures and tissue damage.
2Device complexity
If conventional TMS coils are used to stimulate deep brain regions, then the device complexity is reduced, but the efficacy of stimulating deep neuronal structures is poor due to high decay of magnetic and electric field with distance
Solution Approach 1:
The coil design transitions from a traditional two-dimensional planar winding to a three-dimensional configuration where current-carrying elements are distributed around the periphery of a base that conforms to the scalp surface. This dimensional change allows the magnetic field to penetrate deeper into the brain while maintaining adequate field strength, addressing the rapid decay problem without significantly increasing device complexity.
3Illumination intensity
If the coil elements are dense together at a narrow segment, then the magnetic field intensity is concentrated, but the distribution of electric field in the brain becomes non-optimal for targeting specific deep regions
Solution Approach 1:
The coil elements are segmented and distributed around the periphery of the base rather than concentrated at a narrow segment. This distribution creates a more uniform magnetic field pattern that better targets specific deep brain regions while avoiding excessive field concentration that would cause non-optimal electric field distribution in the brain.
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 coils achieve targeted neuronal stimulation with reduced side effects by optimizing electric field distribution and intensity, ensuring effective activation of deep brain regions while minimizing superficial stimulation and motor activation.
Implementation Method 1
passing high currents by a stimulator through an electromagnetic coil externally placed upon the patient (for example, placed on the scalp for brain treatment), inducing electrical currents in the underlying tissue
Implementation Method 2
The pulses are administered by passing high currents by a stimulator through an electromagnetic coil externally placed upon the patient, inducing electrical currents in the underlying tissue
Data Source
Figure 1
Figure 2A~2C
Figure 2D
AI summary
The invention provides a coil for magnetic stimulation, the coil (10) comprising, a base portion (12) having a base portion right side (16) and a base portion left side (18) on two sides of a central axis (14), wherein said base portion right side (16) has multiple right side stimulating elements (20) spaced apart from one another by a first distance, and said base portion left side (18) has multiple left side stimulating elements (22) spaced apart from one another by said first distance, wherein said base portion right side (16) and said base portion left side (18) are separated from one another by a central distance of 2 to 8 centimetres; a return portion (32) having a return portion right side and a return portion left side, wherein said return portion right side includes right side return elements (40) which are contacting return elements, and said return portion left side includes left side return elements (42) which are contacting return elements; and connecting elements connecting said right side stimulating elements (20) to said right side return elements (40) and connecting said left side stimulating elements (22) to said left side return elements (42), wherein said connecting elements are curved, such that said base portion right side (16), said return portion right side and said connecting elements form a right coil portion having a substantially circular shape, said base portion left side (18), said return portion left side and said connecting elements form a left coil portion having a substantially circular shape.