Modular Brain Stimulation Circuit for Artifact-Free EEG Recording
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Solution Overview
Problem
Simultaneous transcranial direct current stimulation (tDCS) and electroencephalography (EEG) recording is challenging due to signal artifacts, particularly electrode saturation and the difficulty in obtaining real-time electrophysiological data during ongoing stimulations, which hinders understanding of tDCS effects on neural activity.
Innovation Solution
A modular electrical stimulation circuit incorporating multiple electrical stimulators, electrodes, a crossbar switch, and a processing unit, along with transceiver modules, DC canceller, echo canceller, band-pass filters, and amplifiers, allows for simultaneous electrical stimulation and high-resolution EEG recording, enabling the measurement of electrical impedance and improved electrode positioning for effective brain stimulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If simultaneous tDCS and EEG recording is performed, then real-time electrophysiological data during brain stimulation can be obtained, but signal artifacts and electrode saturation occur
Solution Approach 1:
The patent segments the EEG recording system into multiple independent channels with separate amplifiers and processing units for each electrode. This segmentation allows independent processing of signals from different electrodes, preventing artifact propagation across the entire system and enabling selective filtering of stimulation artifacts from neural signals.
Solution Approach 2:
The patent introduces an intermediary signal processing layer between the EEG electrodes and the final recording output. This intermediary processing system includes artifact rejection algorithms and adaptive filtering that act as mediators to separate stimulation artifacts from genuine neural signals, allowing simultaneous recording without contamination.
2Measurement precision
If high-resolution EEG recording is used during tDCS, then real-time cortical activity can be measured, but electrode saturation occurs
Solution Approach 1:
The patent implements dynamic gain control and adaptive filtering that adjust in real-time based on signal characteristics. The system dynamically modifies amplifier gain and filter parameters to prevent saturation while maintaining high-resolution recording, allowing the system to adapt to changing signal conditions during tDCS stimulation.
Solution Approach 2:
The patent changes key parameters of the recording system including amplifier gain, filter cutoff frequencies, and sampling rates based on the presence and intensity of stimulation artifacts. By dynamically adjusting these parameters, the system maintains optimal recording quality while preventing electrode saturation during simultaneous tDCS-EEG recording.
3Manufacturing precision
If multiple electrical stimulators are used for brain stimulation, then stimulation coverage and precision are improved, but system complexity increases
Solution Approach 1:
The patent designs a universal stimulation platform where multiple stimulators share common infrastructure including a single integrated control unit, unified electrode interface, and centralized signal processing system. This multi-functional design allows precise stimulation of multiple brain regions while avoiding proportional increase in overall system complexity through resource sharing and modular architecture.
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 solution enables the acquisition of high-resolution electrophysiological data during brain stimulation, reducing signal artifacts and providing insights into real-time effects of tDCS on cortical activity, facilitating its clinical applications.
Implementation Method 1
a first electrical stimulator configured to generate a first electrical signal and inject the first electrical signal into the brain through a first electrode of the plurality of electrodes
Implementation Method 2
measuring a voltage difference between a pair of electrodes of the plurality of electrodes by a transceiver module
Implementation Method 3
The DC canceller module may be configured to suppress DC data of input node P1
Implementation Method 4
The echo canceller module may be configured to suppress echoes of AC data of the input node P1
Implementation Method 5
a first band-pass filter connected to input node P1 through a buffer B1 and a switch S10
Implementation Method 6
The differential amplifier may be configured to load an amplification of a difference between data on the first differential input node and data on the second differential input node to the differential output node
Implementation Method 7
an analog-to-digital converter (ADC) connected to an output of the anti-aliasing filter
Implementation Method 8
obtaining an electrical impedance map of the brain by an electrical impedance tomography (EIT) imaging process
Data Source
AI summary
A circuit for electrical stimulation of a brain is disclosed. The circuit may include a plurality of electrical stimulators, a plurality of electrodes, a crossbar switch, and a processing unit. Each of the plurality of electrical stimulators is configured to generate an electrical signal. The crossbar switch includes a plurality of individual switches. The processing unit is configured to provide a connection between at least one of the plurality of electrical stimulators and a first electrode of the plurality of electrodes through an individual switch of the plurality of individual switches by turning on the individual switch.