Optimized Concentric Ring Electrode Radii for EEG Laplacian
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Solution Overview
Problem
Existing EEG technologies face challenges such as poor spatial resolution, selectivity, and low signal-to-noise ratio, and have not fully utilized variations in concentric ring electrode (CRE) geometry to improve performance.
Innovation Solution
A system and method for determining optimized radii for a plurality of rings in a concentric ring electrode (CRE) by estimating the dependence of an electrostatic potential's functional on the total radius, ring radii, and potential differences, and minimizing the absolute value of a remaining truncation term to determine optimum ring radii.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional single pole disc electrodes are used for EEG measurement, then the system is simple to implement, but the spatial resolution and signal-to-noise ratio are poor
Solution Approach 1:
The patent divides a single electrode into multiple concentric rings (at least two rings with different radii), where each ring functions as an independent measurement element. This segmentation allows the electrode to capture potential differences at multiple radial distances from the center, thereby improving spatial resolution while maintaining a relatively simple overall structure.
Solution Approach 2:
The patent transitions from conventional single-point disc electrodes to concentric ring electrodes that utilize the radial dimension. By measuring potential differences across multiple rings at different radii, the system adds a radial dimension to the measurement, enabling better spatial discrimination without significantly increasing device complexity.
2Measurement precision
If conventional EEG methods are used, then the measurement process is simple, but the signal-to-noise ratio is low
Solution Approach 1:
The measurement process is segmented into multiple potential difference measurements across different ring pairs. By recording potentials at multiple radial distances and combining these measurements, the system enhances the signal-to-noise ratio through spatial filtering, while the measurement methodology remains systematically organized and manageable.
Solution Approach 2:
The patent introduces the concept of surface Laplacian as an intermediary computational step that processes the raw potential difference measurements from multiple rings. This intermediary processing enhances the spatial selectivity and signal-to-noise ratio by emphasizing local potential variations while suppressing noise, without requiring overly complex measurement procedures.
3Measurement precision
If non-optimized CRE geometry is used, then the electrode design and manufacturing are simpler, but the measurement accuracy is reduced
Solution Approach 1:
The patent specifies optimized parameter ranges for ring radii (inner ring radius between 0.2-0.8 times the outer ring radius, with specific preferred values) to maximize measurement accuracy. By providing these optimized parameter specifications, the patent enables manufacturers to achieve high measurement precision without requiring excessively tight manufacturing tolerances, as the optimized geometry inherently compensates for moderate variations.
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 optimized CRE geometry and estimation methods improve the accuracy of surface Laplacian measurement, leading to better spatial selectivity, signal-to-noise ratio, and mutual information compared to conventional EEG systems, resulting in improved diagnostic and preventive measures.
Implementation Method 1
estimate the surface Laplacian, the second spatial derivative of the potentials on the scalp surface for the case of electroencephalogram (EEG), directly at each electrode
Data Source
AI summary
A concentric ring electrode (CRE) is provided that can sense characteristics of an electrostatic potential, such as its Laplacian, more accurately than previous systems. The disclosed techniques can include receiving information specifying a geometrical configuration of the CRE. The CRE can include an inner ring and an outer ring. The disclosed techniques can also include estimating a dependence of a functional of the electrostatic potential on a set of potential differences comprising at least a first potential difference corresponding to the inner ring and a second potential difference corresponding to the outer ring. Estimating the dependence can include determining a null space of a matrix associated with a series expansion of the electrostatic potential for the geometrical configuration and determining, based on the null space, a set of coefficients for the dependence.