Deep Brain Stimulation Coupling Matrix for Impedance Mapping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for determining stimulation settings for deep brain stimulation probes require imaging devices and indirect estimation of electrical conductivity, which is impractical for updating due to tissue changes over time and limited resolution.
Innovation Solution
A method involving sequential application of test currents to stimulation electrodes, measuring excitation voltages, and deriving a coupling matrix to determine the relation between stimulation settings and the corresponding electrical field in brain tissue, eliminating the need for imaging devices and providing accurate, detailed electrical property measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If MRI/DTI imaging devices are used to obtain conductivity maps, then electrical conductivity information can be obtained, but the method becomes impractical for regular updates due to tissue changes over time and has limited resolution
Solution Approach 1:
The patent extracts the essential measurement function from complex MRI/DTI imaging devices and implements it using simple electrical impedance measurements through the stimulation electrodes themselves. By measuring impedance between electrode pairs, the system obtains electrical conductivity information without requiring external imaging equipment, thus eliminating device complexity while maintaining measurement capability
Solution Approach 2:
The DBS stimulation system performs its own electrical property measurements using its existing electrodes and control circuitry. The stimulation device sequentially applies test currents and measures resulting voltages to derive tissue electrical properties, eliminating the need for separate imaging devices and enabling self-updating of conductivity maps
2Reliability
If DTI scanning is performed regularly to update conductivity maps, then tissue changes can be tracked, but the procedure becomes unpractical due to time consumption and patient burden
Solution Approach 1:
The system enables continuous monitoring of electrical properties by performing impedance measurements during routine stimulation periods. Instead of requiring periodic DTI scans, the stimulation device continuously or frequently measures tissue electrical properties using the same electrodes, maintaining up-to-date conductivity information without interrupting patient care or requiring additional scanning time
Solution Approach 2:
The system implements feedback by using measured impedance values to update the electrical conductivity map, which then informs optimization of stimulation settings. This closed-loop approach ensures the conductivity map remains accurate over time by continuously incorporating new measurement data, eliminating the need for time-consuming periodic re-scanning
3Measurement precision
If DTI resolution is limited to about 2 mm, then scanning time can be kept practical, but the resolution is 4 times the typical electrode pitch and insufficient for high resolution DBS probes
Solution Approach 1:
The patent applies local quality by making measurements at multiple discrete electrode locations along the probe. By sequentially activating different electrode pairs and measuring local impedance values, the system obtains high-resolution electrical property data at each electrode site, matching the spatial distribution of the DBS electrodes themselves rather than using coarse whole-brain imaging
4Ease of manufacture
If sequential test current application and voltage measurement is performed, then detailed electrical property information can be obtained without imaging devices, but multiple measurements are required to build the coupling matrix
Solution Approach 1:
The system performs preliminary characterization measurements during the initial implant procedure or a dedicated calibration session. By completing the full set of impedance measurements and building the coupling matrix upfront, the electrical properties are established before clinical use begins, minimizing the impact of measurement time on ongoing patient treatment
Solution Approach 2:
The system implements periodic updating of the coupling matrix by repeating impedance measurements at scheduled intervals or when changes in stimulation response are detected. This approach balances the need for accurate electrical property data with clinical time constraints by updating measurements only when necessary rather than continuously
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 more practical and accurate determination of stimulation settings without imaging devices, allowing for easier updates due to tissue changes and providing detailed information on electrical properties close to each electrode, improving the precision of stimulation settings and expected V-fields.
Implementation Method 1
measuring a resulting excitation voltage at m stimulation electrodes... deriving an (m*n) coupling matrix, an element Zq,p in the coupling matrix reflecting an amount of electrical impedance between two of the stimulation electrodes
Data Source
AI summary
A method and system are provided for determining a relation between stimulation settings for a brain stimulation probe and a corresponding V-field. The brain stimulation probe comprises multiple stimulation electrodes. The V-field is an electrical field in brain tissue surrounding the stimulation electrodes. The method comprises sequentially applying a test current to n stimulation electrodes, n being a number between 2 and the number of stimulation electrodes of the brain stimulation probe, for each test current at one of the n stimulation electrodes, measuring a resulting excitation voltage at m stimulation electrodes, m being a number between 2 and the number of stimulation electrodes of the brain stimulation probe, from the stimulation settings and the measured excitation voltages, deriving a coupling matrix, an element in the coupling matrix reflecting an amount of electrical impedance between two of the stimulation electrodes, and using the coupling matrix for determining the relation between the stimulation settings and the corresponding V-field.