Directional Electrical Stimulation Using ECAP Propagation Feedback
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Solution Overview
Problem
Existing medical devices for electrical stimulation lack the ability to effectively adjust therapy parameters based on the propagation characteristics of evoked compound action potentials (ECAPs), leading to potential side effects and inefficiencies in treatment efficacy.
Innovation Solution
A medical device system that determines the propagation characteristics of ECAP signals to adjust parameters such as pulse width, interval, and electrode selection, applying constructive or destructive interference to optimize electrical stimulation therapy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical stimulation therapy is delivered using conventional parameters without adjusting for ECAP propagation characteristics, then the therapy can be provided with simple control, but the treatment effectiveness is suboptimal and side effects such as paresthesia occur
Solution Approach 1:
The system measures ECAP signals and uses the propagation characteristic (time delay between cathodic and anodic phase ECAPs) as feedback to automatically adjust stimulation parameters. This closed-loop feedback mechanism enables the device to adapt therapy delivery to individual patient anatomy and nerve conduction properties, improving treatment effectiveness while the automation reduces perceived control complexity.
Solution Approach 2:
The system changes stimulation parameters (pulse width, phase duration, electrode selection) based on the measured propagation characteristic. By dynamically adjusting these parameters according to the ECAP time delay, the system optimizes therapy delivery for directional activation, enhancing treatment effectiveness without requiring complex manual programming.
2Loss of energy
If stimulation parameters are adjusted to reduce ECAP amplitude in certain directions, then side effects and energy consumption are reduced, but the system requires complex real-time analysis of ECAP signals
Solution Approach 1:
The system uses real-time ECAP signal measurement and propagation characteristic analysis as feedback to determine optimal stimulation parameters that minimize energy consumption. The automated feedback loop eliminates the need for complex manual signal analysis by clinicians, as the device performs the analysis and parameter optimization automatically.
Solution Approach 2:
The system performs self-adjustment of stimulation parameters based on its own ECAP measurements. The device autonomously analyzes its generated ECAP signals, determines the propagation characteristic, and adjusts its own operation to achieve directional activation with minimal energy consumption, without requiring external intervention or complex external analysis equipment.
3Ease of operation
If conventional electrical stimulation is used without considering ECAP propagation characteristics, then the device operation is simple, but directional control of stimulation is insufficient leading to undesirable side effects
Solution Approach 1:
The system automatically measures ECAP propagation characteristics and uses this feedback to adjust stimulation parameters for directional control. This automation maintains ease of operation as the device performs the complex analysis and adjustment autonomously, while effectively reducing side effects through precise directional activation.
Solution Approach 2:
The system dynamically changes stimulation parameters (pulse width, phase duration, electrode selection) based on measured ECAP propagation characteristics. These automated parameter adjustments enable directional control to minimize side effects without requiring the user to manually configure complex parameters, preserving ease of operation.
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
This approach reduces side effects and improves treatment efficacy by minimizing ECAP amplitude in certain directions and optimizing energy usage, enhancing therapeutic outcomes.
Implementation Method 1
A medical device may deliver electrical stimulation therapy via one or more leads that include electrodes located proximate to target locations associated with the brain, the spinal cord, pelvic nerves, peripheral nerves, or the gastrointestinal tract of a patient. Electrical stimulation can result in an evoked compound action potential (ECAP) from nerves within the patient.
Implementation Method 2
An ECAP signal may refer to a measure of the nerve tissue's response to stimulation. The first ECAP signal and the second ECAP signal may result in a set of ECAP signals that may be detected by sensing circuitry.
Implementation Method 3
The time delay between the first ECAP signal and the second ECAP signal may result in a destructive interference (e.g., lower amplitude due to the propagation parameter) or constructive interference (e.g., a higher amplitude due to the propagation parameter).
Implementation Method 4
Medical devices can provide more effective therapy by adjusting, based on the propagation characteristic, one or more parameters that define stimulation. Reducing the ECAP amplitude using destructive interference may help to improve treatment
Data Source
AI summary
For example, a system includes stimulation generation circuitry configured to deliver a multiphasic stimulation pulse to the patient and sensing circuitry configured to sense a composite evoked compound action potential (ECAP) signal elicited by the multiphasic stimulation pulse. The system further includes processing circuitry electrically connected to the sensing circuitry and the stimulation generation circuitry, the processing circuitry being configured to control the stimulation generation circuitry to deliver the multiphasic stimulation pulse that comprises a first phase and a second phase and determine, based on the composite ECAP signal, a propagation characteristic for the composite ECAP signal that is elicited by the multiphasic stimulation pulse.