Paddle Electrode Assembly with Separate Measurement Circuitry
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Solution Overview
Problem
Current neuromodulation systems face challenges in maintaining appropriate neural recruitment for therapeutic effects while minimizing energy expenditure and addressing artefacts generated during neural stimulation, which affects the accuracy of neural response measurements.
Innovation Solution
An implantable device with a paddle electrode assembly that includes a plurality of electrodes on a ventral and dorsal surface, featuring stimulation and measurement circuitry, and an electrode selection module to optimize electrode configuration for effective neural stimulation and response measurement, reducing artefacts and improving recruitment efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stimulus intensity is increased to maintain therapeutic effect, then neural recruitment is improved, but uncomfortable or painful percepts arise due to over-recruitment of Aβ fibres
Solution Approach 1:
The electrode array is divided into multiple independently controllable electrodes or electrode groups, allowing selective stimulation of different neural fibre populations. By segmenting the stimulation target, the system can preferentially activate Aδ fibres for pain relief while minimizing Aβ fibre recruitment that causes uncomfortable sensations.
Solution Approach 2:
Different regions of the electrode array are configured with different stimulation parameters (intensity, pulse width, frequency) tailored to local neural anatomy and fibre types. This allows optimized stimulation at each location to achieve therapeutic effect while avoiding uncomfortable percepts in specific dermatomal regions.
2Reliability
If electrode array position changes due to migration or postural changes, then neural recruitment efficacy is altered, but maintaining appropriate stimulus intensity becomes difficult
Solution Approach 1:
The system incorporates measurement electrodes that continuously monitor neural recruitment indicators (such as evoked compound action potentials or impedance changes). This feedback signal is used by the controller to dynamically adjust stimulation parameters, maintaining optimal therapeutic effect despite electrode migration or patient posture changes.
Solution Approach 2:
The stimulation parameters are made dynamically adjustable rather than fixed, allowing real-time adaptation to changing physiological conditions. The system can modify pulse width, frequency, and intensity based on detected neural response, ensuring consistent therapeutic effect regardless of positional changes.
3Reliability
If multiple electrodes are used for stimulation, then neural recruitment is improved, but artefacts generated during stimulation affect the accuracy of neural response measurements
Solution Approach 1:
The measurement function is extracted from the stimulating electrodes by using separate dedicated measurement electrodes. This separation allows accurate recording of neural responses without contamination from stimulation artefacts, while still utilizing multiple stimulating electrodes for effective neural recruitment.
Solution Approach 2:
Differential measurement techniques are employed where the neural response is measured as a potential difference between two electrodes rather than relative to ground. This intermediary measurement approach rejects common-mode stimulation artefacts while preserving the neural signal of interest.
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 solution enables precise control of neural stimulation, maintaining therapeutic intensity within a comfortable range, reducing energy consumption, and enhancing the accuracy of neural response measurements, thus improving the efficacy of neuromodulation therapies.
Implementation Method 1
A neuromodulation system applies an electrical pulse (stimulus) to neural tissue (fibres, or neurons) in order to generate a therapeutic effect
Implementation Method 2
measurement circuitry, configured to measure a response evoked from the neural target by the stimulation energy and sensed by one or more electrodes of the paddle electrode assembly
Data Source
AI summary
An implantable device for controllably stimulating a neural target. The device configured to electrically couple to a paddle electrode assembly, the paddle electrode assembly comprising a plurality of electrodes including a first group of one or more electrodes arranged on a ventral surface of a paddle body, and a second group of one or more electrodes arranged on a dorsal surface of the paddle body. The implantable device comprises stimulation circuitry, configured to provide stimulation energy to one or more electrodes of the paddle electrode assembly, measurement circuitry, configured to measure a response evoked from the neural target by the stimulation energy and sensed by one or more electrodes of the paddle electrode assembly, and an electrode selection module. The electrode selection module is configured to select at least one first electrode from the plurality of electrodes of the paddle electrode assembly and electrically couple the first electrode to the stimulation circuitry, and select at least one second electrode from the plurality of electrodes of the paddle electrode assembly and electrically couple the second electrode to the measurement circuitry.