Neuromodulation IC for Concurrent Stimulation and Neural Recording
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Solution Overview
Problem
Current medical devices for neuromodulation struggle with true closed-loop operation due to interference between stimulation and recording, leading to saturation and long-lasting artifacts that corrupt neural signals, limiting real-time control and feedback.
Innovation Solution
The development of a neuromodulation apparatus with co-designed recording and stimulation subsystems that minimize interference through charge balance, common voltage reference, large linear input voltage range, and fast recovery, enabling concurrent or nearly concurrent electrical sensing and stimulation with minimal artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stimulation is delivered through electrodes, then therapeutic effect is achieved, but recording circuits become saturated and produce long-lasting artifacts that corrupt neural signals
Solution Approach 1:
The patent segments the electrode array into stimulation electrodes and recording electrodes, allowing simultaneous operation without mutual interference. The recording electrodes are positioned to detect neural activity while stimulation electrodes deliver therapeutic pulses, physically separating the harmful stimulation effect from the sensitive recording function.
Solution Approach 2:
The patent implements artifact suppression circuitry that actively counteracts stimulation artifacts before they corrupt the neural signal. The system predicts artifact timing and amplitude based on stimulation parameters and subtracts these predicted artifacts from the recorded signal in real-time, preventing artifact saturation of the recording circuits.
2Productivity
If recording and stimulation are performed simultaneously, then real-time closed-loop feedback is achieved, but interference between subsystems corrupts the recorded signals
Solution Approach 1:
The patent introduces artifact suppression circuitry as an intermediary between the stimulation and recording subsystems. This intermediary actively monitors stimulation parameters, predicts resulting artifacts, and subtracts them from the recorded signal, allowing simultaneous operation while preserving neural signal integrity.
Solution Approach 2:
The system implements real-time feedback by continuously monitoring neural activity through recording electrodes and immediately adjusting stimulation parameters based on the detected neural state. The artifact suppression enables this closed-loop operation by eliminating the corruption that would otherwise prevent accurate real-time detection.
3Measurement precision
If conventional separate-time recording and stimulation is used, then signal quality is maintained, but real-time control and closed-loop feedback are limited
Solution Approach 1:
The patent enables continuous simultaneous recording and stimulation through artifact suppression technology. Unlike conventional systems that must alternate between recording and stimulation modes, this system maintains both functions continuously and concurrently, eliminating the time loss associated with switching between modes while preserving signal quality through active artifact removal.
Data Source
AI summary
Representative methods, apparatus and systems are disclosed for providing concurrent electrical stimulation and electrical recording in a human or non-human subject, such as for neuromodulation, with the apparatus coupleable to an electrode array. A representative apparatus is typically an integrated circuit including: stimulation circuits, recording circuits, and blocking circuits responsive to control signals to block the stimulation voltage or current on an electrode from a corresponding recording circuit, while other recording circuits may simultaneously record electrical signals from other electrodes and generate recorded data. A representative stimulation circuit may include current sources; a first multiplexer for current source selection; a second multiplexer for electrode selection; a switchable voltage offset circuit; a switchable grounding circuit; and a stimulation controller providing control signals to provide the electrical stimulation, such as biphasic or monophasic stimulation, and bipolar or unipolar stimulation. Off-chip communication, control, along with power and voltage level control, are also provided.