Closed-Loop Spinal Cord Stimulation for Evoked Response Avoidance
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Solution Overview
Problem
Conventional sub-perception Spinal Cord Stimulation (SCS) therapies suffer from prolonged wash-in time, high power consumption, and complex therapy optimization, with existing systems failing to effectively and efficiently detect and maintain small evoked neural activities below detection thresholds.
Innovation Solution
A closed-loop control system for electrostimulation that adjusts stimulation parameters in response to detected evoked neural activities, using a feedback mechanism to maintain these activities at or below a specified threshold, thereby optimizing power usage and therapeutic efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sub-perception SCS uses higher-frequency pulses to achieve paresthesia-free effect, then analgesia effect is achieved, but power consumption increases and battery life shortens
Solution Approach 1:
The system dynamically adjusts stimulation frequency based on detected evoked neural activity. The controller monitors evoked responses and modulates the stimulation frequency in real-time to maintain therapeutic effect while minimizing power consumption, transitioning from fixed high-frequency to adaptive frequency modulation
Solution Approach 2:
The system implements a closed-loop feedback mechanism where evoked neural activities are detected and used to adjust stimulation parameters. The controller receives feedback from evoked response detection and recursively adjusts stimulation frequency to optimize both therapeutic efficacy and energy efficiency
2Reliability
If conventional sub-perception SCS delivers stimulation pulses to achieve analgesia, then pain relief is achieved, but wash-in time is prolonged
Solution Approach 1:
The system performs preliminary detection of evoked neural activities before establishing full therapeutic stimulation. By detecting and characterizing neural responses in advance, the system can optimize stimulation parameters upfront, eliminating the prolonged wash-in period required by conventional approaches
Solution Approach 2:
The system replaces the conventional time-dependent wash-in mechanism with an active detection and adaptation mechanism. Instead of relying on gradual tissue adaptation over hours or days, the system actively monitors evoked responses and adjusts parameters in real-time to achieve immediate therapeutic effect
3Reliability
If conventional sub-perception SCS maintains stimulation to achieve pain relief, then therapeutic effect is achieved, but therapy optimization becomes complex and onerous
Solution Approach 1:
The system performs self-optimization by automatically detecting evoked neural activities and adjusting stimulation parameters without external intervention. The controller recursively modifies stimulation frequency based on detected responses, eliminating the need for complex manual therapy optimization procedures
Data Source
AI summary
Systems and methods for closed-loop control of electrostimulation while avoiding, or maintaining a substantially low level of, evoked neural activity are disclosed. A system comprises an electrostimulator to deliver a stimulation pulse train, a sensing circuit to sense evoked responses to respective pulses in the pulse train, and a controller to detect an evoked neural activity from an averaged evoked response by averaging evoked responses to respective pulses. The averaging operation can be controlled by a noise level of the averaged evoked response, or by a count of epochs (pulses) being used for averaging. Responsive to the evoked neural activity satisfying a detection criterion, the controller recursively adjusts stimulation parameters until the detection criterion is no longer satisfied. The electrostimulator delivers electrostimulation according to the recursively adjusted stimulation parameters.