Branching Conductivity Passages for Uniform tDCS Current Distribution
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Solution Overview
Problem
Existing transcranial direct current stimulation (tDCS) electrodes often produce localized current densities that can be painful and uncomfortable for subjects, necessitating the development of electrodes with lower current densities at their outer edges.
Innovation Solution
The design of electrode interfaces and assemblies featuring a body with non-contact and contact surfaces, incorporating conductivity passages along a central axis with branching inlets and subpassages that diverge to distribute current more evenly, reducing maximum current density at the edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional electrodes are used for tDCS, then current delivery is achieved, but localized current densities at outer edges cause pain and discomfort
Solution Approach 1:
The electrode interface is divided into multiple conductivity passages that branch into multiple subpassages and branches, distributing the current delivery path into numerous smaller channels. This segmentation prevents current concentration at the outer edges by creating a distributed network of current pathways throughout the electrode interface.
Solution Approach 2:
The conductivity passages are configured with varying geometries and orientations to create non-uniform current density distribution across the electrode interface. The branching structure ensures that different regions of the electrode interface have optimized local properties for current distribution, with higher density in central regions and lower density at edges.
2Object-affected harmful factors
If current density is reduced to improve comfort, then discomfort is decreased, but stimulation effectiveness may be compromised
Solution Approach 1:
The current distribution problem is solved by transitioning from a two-dimensional surface current delivery to a three-dimensional branching passage system. The conductivity passages extend through the electrode interface thickness, creating volumetric current distribution pathways that maintain total current delivery while reducing surface current density through the branching architecture.
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
This design effectively reduces maximum current density to less than 4 A/m2, enhancing comfort during tDCS by distributing current more uniformly, as demonstrated by computer modeling showing maximum current densities of 2.73 to 2.98 A/m2.
Implementation Method 1
the body defines a plurality of conductivity passages extending therethrough from the non-contact surface to the contact surface
Data Source
AI summary
Electrode interfaces and electrode assemblies for performing transcranial direct current stimulation. The electrode interfaces include a body configured to be coupled to an electrode for delivery of electrical current therethrough. The body includes a non-contact surface and a contact surface opposing the non-contact surface. The body defines a plurality of conductivity passages extending therethrough from the non-contact surface to the contact surface. Each conductivity passage is disposed along a central axis and includes at least one branching inlet and at least one branching subpassage extending from the at least one branching inlet to the contact surface. Each branching subpassage defines a plurality of branches, and each branch diverges from the central axis and then extends to the contact surface. The electrode assemblies include a neurostimulation device, at least two electrodes coupled to the neurostimulation device, and an electrode interface including a body coupled to each electrode.