A Tripolar Electromyography Device With Active Electrode-Skin Impedance Imbalance Compensation

2021 ◽  
Author(s):  
Alexander J. Towse ◽  
Benjamin C. Fortune ◽  
Chistopher G. Pretty ◽  
Michael P. Hayes
Keyword(s):  
Marked Reduction ◽  
Development Process ◽  
Skin Impedance ◽  
Signal Quality ◽  
Electrode Impedance ◽  
Compensation Circuit ◽  
Limited Effect ◽  
Active Electrode ◽  
Emg Signal ◽  
Electrical Interference

Abstract This paper discusses the development of a tripolar EMG device featuring electrode impedance compensation circuitry. The device also includes circuitry to test the effectiveness of these features at improving EMG signal quality. Due to various factors, the electrode-skin impedance of different electrodes is typically imbalanced. This imbalance increases EMG susceptibility to electrical noise. These issues can be mitigated by applying impedance compensation. This was done for a tripolar configuration specifically to also reduce interference due to crosstalk. The development process and design choices behind the device features are discussed, with particular focus on the impedance compensation circuit. This includes key components used, and the justification behind their selection. Testing found the tripolar electrode configuration had limited effect on crosstalk interference. Fortunately, the impedance compensation circuit could successfully correct for impedance imbalance. This led to a marked reduction in noise due to electrical interference, such as from 50Hz mains hum.

scholarly journals The Effect of Sleeve Pattern and Fit on E-Textile Electromyography (EMG) Electrode Performance in Smart Clothing Design

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5621
Author(s):  
Gozde Goncu-Berk ◽  
Bilge Guvenc Tuna
Keyword(s):  
Signal To Noise Ratio ◽  
Arm Movement ◽  
The Body ◽  
Superior Performance ◽  
Skin Impedance ◽  
Signal Quality ◽  
Electrode Performance ◽  
Smart Clothing ◽  
Emg Signal ◽  
Textile Electrode

When e-textile EMG electrodes are integrated into clothing, the fit of the clothing on the body, and therefore its pattern and cut become important factors affecting the EMG signal quality in relation to the seamless contact between the skin and the e-textile electrode. The research so far on these effects was conducted on commercially available clothing or in tubular sleeve forms for arms. There is no study that investigated different clothing pattern and fit conditions and their effect on e-textile EMG electrode performance. This study investigates the effect of clothing pattern and fit in EMG applications using e-textile electrodes integrated onto the sleeves of custom drafted t-shirts in set-in and raglan sleeve pattern variations. E-textile electrode resistance, signal-to-noise ratio (SNRdB), power spectral density and electrode–skin impedance are measured and evaluated in set-in sleeve and raglan sleeve conditions with participants during a standardized arm movement protocol in comparison to the conventional hydrogel Ag/AgCl electrodes. The raglan sleeve pattern, widely used in athletic wear to provide extra ease for the movement of the shoulder joint, showed superior performance and therefore indicated the pattern and cut of a garment could have significant effect on EMG signal quality in designing smart clothing.

scholarly journals Novel dry electrode EEG headbands for home use: Comparing performance and comfort

2020 ◽  
Vol 6 (3) ◽  
pp. 139-142
Author(s):  
Jens Haueisen ◽  
Patrique Fiedler ◽  
Anna Bernhardt ◽  
Ricardo Gonçalves ◽  
Carlos Fonseca
Keyword(s):  
Brain Activity ◽  
Skin Impedance ◽  
Signal Quality ◽  
The Novel ◽  
Application Time ◽  
Dry Electrodes ◽  
Power Spectral ◽  
Dry Electrode ◽  
Increasing Trend ◽  
Eeg Recordings

AbstractMonitoring brain activity at home using electroencephalography (EEG) is an increasing trend for both medical and non-medical applications. Gel-based electrodes are not suitable due to the gel application requiring extensive preparation and cleaning support for the patient or user. Dry electrodes can be applied without prior preparation by the patient or user. We investigate and compare two dry electrode headbands for EEG acquisition: a novel hybrid dual-textile headband comprising multipin and multiwave electrodes and a neoprene-based headband comprising hydrogel and spidershaped electrodes. We compare the headbands and electrodes in terms of electrode-skin impedance, comfort, electrode offset potential and EEG signal quality. We did not observe considerable differences in the power spectral density of EEG recordings. However, the hydrogel electrodes showed considerably increased impedances and offset potentials, limiting their compatibility with many EEG amplifiers. The hydrogel and spider-shaped electrodes required increased adduction, resulting in a lower wearing comfort throughout the application time compared to the novel headband comprising multipin and multiwave electrodes.

scholarly journals Wearable Active Electrode for sEMG Monitoring Using Two-Channel Brass Dry Electrodes with Reduced Electronics

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
J. Antonio Ruvalcaba ◽  
M. I. Gutiérrez ◽  
A. Vera ◽  
L. Leija
Keyword(s):  
Sports Medicine ◽  
Clinical Analysis ◽  
Skin Impedance ◽  
Signal Acquisition ◽  
Wrist Flexion ◽  
Semg Signal ◽  
Active Electrode ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Low Pass

Gel-based electrodes are employed to record sEMG signals for prolonged periods. These signals are used for the control of myoelectric prostheses, clinical analysis, or sports medicine. However, when the gel dries, the electrode-skin impedance increases considerably. Using dry active electrodes (AEs) to compensate variations of impedance is an alternative for long-term recording. This work describes the optimization of the electronic design of a conventional AE by removing the impedance coupling stage and two filters. The proposed work consisted of 5 stages: electrodes, amplification (X250), 2.2 Vdc offset, low-pass filter, and ADC with USART communication. The device did not need the use of electrolytic gel. The measurements of CMRR (96 dB), amplitude of the output sEMG signal (∼1.6 Vp-p), and system bandwidth (15–450 Hz) were performed in order to confirm the reliability of the device as an sEMG signal acquisition system. The SNR values from seven movements performed by eleven volunteers were compared in order to measure the repeatability of the measurements (average 30.32 dB for a wrist flexion). The SNR for wrist flexion measured with the proposed and the commercial system was compared; the values were 49 dB and 60 dB, respectively.

Soft Conductive Polymer Dry Electrodes for High-Quality and Comfortable ECG/EEG Measurements

2014 ◽  
Vol 96 ◽  
pp. 102-107 ◽  
Author(s):  
Yun Hsuan Chen ◽  
Maaike Op de Beeck ◽  
Luc Vanderheyden ◽  
Kris Vanstreels ◽  
Herman Vandormael ◽  
...  
Keyword(s):  
Skin Irritation ◽  
Conductive Polymer ◽  
Hard Metal ◽  
Motion Artifacts ◽  
Patient Comfort ◽  
Signal Quality ◽  
Electrode Impedance ◽  
High Quality ◽  
Dry Electrode ◽  
User Comfort

Wet gel electrodes are widely used for ECG/EEG monitoring, their low impedance results in high-quality signals. But they have important drawbacks too, such as time-consuming electrode set-up for EEG followed by a painful removal, skin irritation by the gel and signal degradation due to gel drying. Hence various dry electrode types are investigated, such as hard metal electrodes with low impedance but limited patient comfort/safety. We focus on flexible conductive polymer-based electrodes to combine low impedance, user comfort and safety. The composition of the conductive polymers is optimized to improve various properties such as conductivity, which directly affects signal quality and sensitivity to motion artifacts, and mechanical properties of the electrodes, important with respect to patient comfort. Electrode impedance and ECG/EEG signal recordings are evaluated using various polymer compositions and compared to wet gel electrode results. Additive optimization to improve processability of the conductive formulations is performed by dedicated flow studies, and will result in a high electrode fabrication yield. Very promising results are obtained regarding impedance, EEG/ECG signal quality and user comfort.

scholarly journals Applying Noncontact Sensing Technology in the Customized Product Design of Smart Clothes Based on Anthropometry

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 7978
Author(s):  
I-Jan Wang ◽  
Wei-Ting Chang ◽  
Wen-Hao Wu ◽  
Bor-Shyh Lin
Keyword(s):  
Product Design ◽  
Development Process ◽  
Skin Irritation ◽  
Three Dimensional ◽  
Motion Artifacts ◽  
Signal Quality ◽  
Conductive Materials ◽  
Dry Electrodes ◽  
Sensing Technology

Electrocardiograms (ECGs) provide important information for diagnosing cardiovascular diseases. In clinical practice, the conventional Ag/AgCl electrode is generally used; however, it is not suitable for long-term ECG measurement because of the risk of allergic reactions on the skin and the dying issue of electrolytic gels. In previous studies, several dry electrodes have been proposed to address these issues. However, most dry electrodes, which are the mode of conductive materials, have to contact the skin well and are easily affected by motion artifacts in daily life. In the smart clothes developed in this study, a noncontact electrode was used to assess the biopotential across the clothes to prevent skin irritation and discomfort. Moreover, a three-dimensional parametric model based on anthropometric data was built, and the technique of customized product design was introduced into the smart clothes development process to reduce the influence of motion artifacts. The experimental results show that the proposed smart clothes can maintain a good ECG signal quality stably under motion from different activities.

Air entrapment and differential swelling as factors in the mellowing of molded soil during rapid wetting

Soil Research ◽  
1990 ◽  
Vol 28 (3) ◽  
pp. 361 ◽  
Author(s):  
CD Grant ◽  
AR Dexter
Keyword(s):  
Tensile Strength ◽  
Quantitative Estimate ◽  
Marked Reduction ◽  
Ambient Air ◽  
Parallel Plates ◽  
Air Entrapment ◽  
Limited Effect ◽  
Sintered Glass ◽  
Wetting Fluids ◽  
Dry Soil

The two principal mechanisms thought to be responsible for the mellowing (or weakening) of moulded soils during rapid wetting are air entrapment and differential swelling. These were investigated in order to obtain a quantitative estimate of the effect each mechanism has on the tensile strength of soils. Rapid wetting experiments were conducted on dry soil discs which had been prepared from moulded moist soil. The discs were wetted on sintered-glass funnels using two different wetting fluids at three different ambient air pressures. Discs were dried again and crushed between flat parallel plates to determine their tensile strengths. For the two soils used in this study, it was found that air entrapment on its own did not generate sufficient stress to induce mellowing, and furthermore that differential swelling on its own also had a limited effect. When the two processes acted simultaneously, however, a marked reduction in the tensile strength of between 35% and 47% resulted.

Design and implementation of low-power CMOS biosignal amplifier for active electrode in biomedical application using subthreshold biasing strategy

2019 ◽  
Vol 18 (01) ◽  
pp. 1941017
Author(s):  
G. Kalpana ◽  
Raja Krishnamoorthy ◽  
P. T. Kalaivaani
Keyword(s):  
Low Power ◽  
Integrated Circuit ◽  
Digital Signal Processor ◽  
Biomedical Application ◽  
Research Work ◽  
Cmos Technology ◽  
Motion Artifacts ◽  
Skin Impedance ◽  
Cochlear Prosthesis ◽  
Active Electrode

Active Electrodes (AEs) are electrodes which have integrated bio-amplifier circuitry and are known to be less susceptible to motion artifacts and environmental interference. In this work, a low-power and high-input impedance amplifier for active electrode application is implemented based on subthreshold biasing strategies. In this proposed Application Specific Integrated Circuit (ASIC) device was versatile and numerical to achieve a high degree of programmability. It could be adapted to any other external part of one cochlear prosthesis, the sound analyzer that could be driven by a Digital Signal Processor (DSP). This research work also discusses the measurement of the electrode-skin impedance mismatch between two electrodes while concurrently measuring a bioelectrical signal without degradation of the performance of the amplifier, the efficient, noise-optimized analysis of bioelectrical signals utilizing two-wired active buffer electrodes. The reduction of power-line interference when using amplifying electrodes employing autonomous adaption of the gain of the subsequent differential amplification. The amplifier’s features include offset compensation, Common Mode Rejection Ratio (CMRR) improvement in software and a bandwidth extending down to DC. The proposed active electrode amplifier is designed using 90 nm CMOS technology. Simulation results exhibit up to the change in noise immunity and lessening in power utilization contrasted with the traditional bio-amplifier design at a similar delay.

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