Neurostimulation ECAP Signal Detection Using Conditioning Pulses
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Solution Overview
Problem
Conventional spinal cord stimulation (SCS) techniques face challenges in accurately measuring evoked compound action potentials (ECAPs) during paresthesia-free stimulation methods like high-frequency SCS and burst stimulation, as these methods often result in low signal strength or impractical signal-to-noise ratios, making it difficult to assess neural recruitment effectively.
Innovation Solution
The implementation of sensing signal stimulation techniques that utilize pinging-pulses to evoke responsive signals with sufficient strength and signal-to-noise characteristics, allowing for reliable measurement and analysis of ECAPs even in paresthesia-free stimulation regimens, such as burst stimulation, without eliciting paresthesia in patients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If high-frequency SCS or burst stimulation is used to provide paresthesia-free therapy, then patient comfort is improved, but the signal strength of ECAPs becomes too low for reliable measurement
Solution Approach 1:
The system delivers a conditioning pulse before the therapeutic pulse to pre-activate the neural tissue and enhance the ECAP signal amplitude in response to the subsequent therapeutic pulse, making the weak signal from paresthesia-free stimulation measurable
Solution Approach 2:
The conditioning pulse acts as an intermediary that modifies the neural tissue state, creating a more responsive condition that amplifies the ECAP response to the therapeutic pulse without requiring the therapeutic pulse itself to be strong enough to cause paresthesia
2Measurement precision
If stimulation amplitude is increased to improve ECAP signal strength, then measurement precision is improved, but paresthesia is elicited causing patient discomfort
Solution Approach 1:
The conditioning pulse is delivered at a higher amplitude than the therapeutic pulse to generate a strong ECAP signal for measurement, while the actual therapeutic pulse remains at a lower, comfortable amplitude that does not cause paresthesia
Solution Approach 2:
The measurement function and therapeutic function are separated into two distinct pulses: a conditioning pulse optimized for ECAP signal generation and measurement, and a therapeutic pulse optimized for patient comfort and pain relief
3Measurement precision
If conventional SCS with paresthesia is used, then ECAP measurement is reliable, but patient comfort deteriorates due to uncomfortable sensations
Solution Approach 1:
The conditioning pulse prepares the neural tissue in advance to produce a measurable ECAP response from the subsequent low-amplitude therapeutic pulse, eliminating the need to use high-amplitude continuous stimulation that causes paresthesia
Solution Approach 2:
The system uses periodic pairs of conditioning and therapeutic pulses, where the conditioning pulse occurs intermittently to elicit measurable ECAPs while the therapeutic pulse provides continuous low-level stimulation without paresthesia
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 accurate assessment and control of neural recruitment during paresthesia-free SCS therapies, ensuring effective pain management without discomfort, by facilitating the reliable measurement of ECAPs even in low signal conditions.
Implementation Method 1
measuring an evoked neural response in the patient in response to the pinging-pulses
Data Source
AI summary
Systems and methods are disclosed for conducting spinal cord stimulation or other neurostimulation and sensing evoked compound action potential (ECAP) signals. The sensed signals may be processed to isolate ECAP features from noise and/or interfering signals. The isolated ECAP features may be used to control neurostimulation therapy for the patient, such as to quantify or measure lead migration and adjust a neurostimulation therapy for the patient to account for an impact of any detected lead migration, or other purposes (e.g., to guide an implant procedure).