ECAP Lead Integrity Diagnostics for Closed-Loop Stimulation
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Solution Overview
Problem
Existing electrical stimulation therapies face issues with lead integrity and noise interference, such as electromagnetic interference (EMI) and internal noise, which affect the detection and recording of evoked compound action potentials (ECAPs), leading to improper administration of therapy.
Innovation Solution
A medical device system that utilizes ECAP signals in a closed-loop system to adjust stimulation parameters, performs lead integrity tests when characteristic values are outside an expected range, and suspends or adjusts therapy to mitigate noise interference, ensuring accurate therapy delivery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional signal processing methods are used in noisy environments, then signal processing can be performed, but lead integrity and measurement accuracy deteriorate
Solution Approach 1:
The system implements feedback by continuously monitoring the measured impedance signal and comparing it against expected patterns. When deviations indicating lead integrity issues are detected, the system adjusts the measurement parameters or alerts the user, creating a closed-loop system that improves reliability in noisy environments.
Solution Approach 2:
The patent introduces an intermediary signal processing layer that separates the raw impedance signal from the final measurement output. This intermediary layer applies filtering and analysis algorithms that distinguish true tissue impedance changes from noise artifacts, thereby maintaining lead integrity assessment accuracy despite environmental noise.
2Measurement precision
If complex signal processing algorithms are implemented to improve measurement accuracy, then measurement precision improves, but device complexity increases
Solution Approach 1:
The signal processing algorithm is segmented into distinct functional modules: impedance signal acquisition, noise filtering, lead integrity analysis, and tissue characterization. Each module performs a specific function independently, which improves measurement precision while making the overall system more manageable and less complex through modular design.
Solution Approach 2:
The system applies partial signal processing by focusing computational resources on the most critical aspects of impedance analysis - specifically lead integrity detection and significant tissue impedance changes. Less critical frequency components or noise bands receive reduced processing, optimizing the balance between measurement precision and device complexity.
3Ease of operation
If electrical leads are made more flexible and smaller, then ease of operation and patient comfort improve, but lead integrity and signal quality worsen
Solution Approach 1:
The patent replaces mechanical lead integrity assurance with electrical signal-based detection. Instead of relying on the physical robustness of thicker, stiffer leads, the system uses impedance measurements to continuously monitor lead integrity, enabling the use of thinner, more flexible leads without sacrificing reliability.
Solution Approach 2:
An intermediary monitoring system is introduced that detects lead integrity issues through electrical impedance characteristics. This intermediary detection mechanism allows the use of flexible, thin leads by providing continuous surveillance of their condition, compensating for their reduced mechanical strength through enhanced sensing capability.
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 system effectively identifies and mitigates issues with ECAP signal detection, preventing unintended changes in therapy and maintaining consistent treatment efficacy by performing lead integrity tests and adjusting stimulation parameters in response to noise interference.
Implementation Method 1
measuring an electrical impedance of the tissue at a plurality of frequencies
Data Source
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AI summary
In one example, the disclosure describes a method comprising receiving, by processing circuitry, information indicative of one or more evoked compound action potential (ECAP) signals. The one or more ECAP signals are sensed by at least one electrode carried by a medical lead. The processing circuitry determining that at least one characteristic value of the one or more ECAP signals is outside of an expected range. Responsive to determining that the at least one characteristic value of the one or more ECAP signals is outside of the expected range, the processing circuitry performs a lead integrity test for the medical lead.