Electrical Stimulator Shielding for Neurophysiology Artifact Reduction
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Solution Overview
Problem
Stimulation artifacts caused by electrical stimulators in neurophysiology interfere with the evaluation of electrophysiological responses, making it difficult to determine the onset of the response and affecting the quality of measurements.
Innovation Solution
The method involves creating a closed equipotential surface around the electrical stimulator through electrical shielding, providing low capacitive coupling between the stimulator and other device components, and connecting a shielded stimulation electrode to this surface. A collection electrode is placed between the stimulation and recording electrodes to minimize capacitive coupling and redirect electric charge back to the shielding, thereby reducing stimulation artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrical shielding and collection electrode are added to reduce stimulation artifact, then measurement precision is improved, but device complexity increases
Solution Approach 1:
A collection electrode is introduced as an intermediary element between the stimulation electrode and the recording electrode. This collection electrode captures and redirects electric charge back to the shielding, preventing the charge from penetrating into the measuring circuits and causing stimulation artifacts. The intermediary effectively mediates the interaction between stimulation and measurement components.
Solution Approach 2:
The electrical stimulation device is segmented into functionally distinct components: the electrical stimulator enclosed in shielding, the stimulation electrode for delivering pulses, the collection electrode for charge redirection, and the recording electrode for measurement. This segmentation allows each component to perform its specific function while minimizing interference between them.
2Object-affected harmful factors
If collection electrode is placed close to stimulation electrode to maximize artifact reduction, then stimulation artifact is reduced, but the distance constraints make the procedure more difficult
Solution Approach 1:
The solution optimizes the positional parameter of the collection electrode, placing it at a specific distance from the stimulation electrode (at most half the distance between stimulation and recording electrodes). This parameter optimization achieves effective artifact reduction while maintaining practical ease of operation during electrode placement.
3Reliability
If constant stimulation current is maintained regardless of load impedance, then stimulation reliability is improved, but stimulation artifact increases
Solution Approach 1:
The high-voltage constant current stimulation, which generates harmful stimulation artifacts, is combined with the collection electrode system that captures and redirects these artifacts. The harmful electric charge that would normally penetrate into measuring circuits is instead redirected back to the shielding, converting the harmful effect into a controlled phenomenon that benefits the measurement process.
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 significantly reduces the amplitude and duration of stimulation artifacts, improving the clarity of electrophysiological responses and facilitating accurate measurement of neural or muscle responses.
Implementation Method 1
creating a closed equipotential surface around the electrical stimulator through electrical shielding
Implementation Method 2
providing low capacitive coupling between the stimulator and other device components
Data Source
AI summary
A method of reducing stimulation artifact when performing electrical stimulation, in which a stimulation pulse is generated by an electrical stimulator connected to a stimulation electrode. A closed equipotential surface is created around the electrical stimulator by complete electrical shielding of the electrical stimulator from the rest of the electrical stimulator and from the surroundings, a low capacitive coupling is ensured between the electrical stimulator itself and the rest of the device structure, the shielding of the stimulation electrode is connected to the closed equipotential surface of the electrical stimulator and to the closed equipotential surface electrical stimulator and/or a collection electrode designed to be placed on the patient is connected to the shielding of the stimulation electrode. The stimulation artifact reducing electrical stimulation device comprises an electrical stimulator (1) designed to connect to a stimulation electrode. The electrical stimulator (1) is provided with a shield (3) with an electrically shielding surface for shielding the electrical stimulator by creating an equipotential conductive surface surrounding this electrical stimulator (1), wherein the shielding is provided with a connection connector for connection to the shielding of the stimulation electrode or is directly connected to this shielding, and that the shielding (3) of the electrical stimulator (1) and/or to the shielding of the stimulating electrode is designed to be connected to the collecting electrode (6) or is connected to the collecting electrode (6), and that at least between the electrical stimulator (1) and the remaining parts of the device create a low capacitive coupling.