scholarly journals Flexible Multi-Layer Semi-Dry Electrode for Scalp EEG Measurements at Hairy Sites

Micromachines ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 518 ◽  
Author(s):  
Haoqiang Hua ◽  
Wei Tang ◽  
Xiangmin Xu ◽  
David Dagan Feng ◽  
Lin Shu
Keyword(s):  
Temporal Correlation ◽  
Acquisition Time ◽  
Eeg Monitoring ◽  
Foam Layer ◽  
Contact Impedance ◽  
Lower Electrode ◽  
Scalp Eeg ◽  
Dry Electrodes ◽  
Dry Electrode

One of the major challenges of daily wearable electroencephalogram (EEG) monitoring is that there are rarely suitable EEG electrodes for hairy sites. Wet electrodes require conductive gels, which will dry over the acquisition time, making them unstable for long-term EEG monitoring. Additionally, the electrode–scalp impedances of most dry electrodes are not adequate for high quality EEG collection at hairy sites. In view of the above problems, a flexible multi-layer semi-dry electrode was proposed for EEG monitoring in this study. The semi-dry electrode contains a flexible electrode body layer, foam layer and reservoir layer. The probe structure of the electrode body layer enables the electrode to work effectively at hairy sites. During long-term EEG monitoring, electrolytes stored in the reservoir layer are continuously released through the foam layer to the electrode–scalp interface, ensuring a lower electrode–scalp contact impedance. The experimental results showed that the average electrode–scalp impedance of the semi-dry electrode at a hairy site was only 23.89 ± 7.44 KΩ at 10 Hz, and it was lower than 40 KΩ over a long-term use of 5 h. The electrode performed well in both static and dynamic EEG monitoring, where the temporal correlation with wet electrode signals at the hairy site could reach 94.25% and 90.65%, respectively, and specific evoked EEG signals could be collected. The flexible multi-layer semi-dry electrode can be well applied to scalp EEG monitoring at hairy sites, providing a promising solution for daily long-term monitoring of wearable EEGs.

scholarly journals Fully organic compliant dry electrodes self-adhesive to skin for long-term motion-robust epidermal biopotential monitoring

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Lei Zhang ◽  
Kirthika Senthil Kumar ◽  
Hao He ◽  
Catherine Jiayi Cai ◽  
Xu He ◽  
...  
Keyword(s):  
Body Movement ◽  
Deep Tendon Reflex ◽  
Conductive Polymer ◽  
Motion Artifacts ◽  
Contact Impedance ◽  
Skin Contact ◽  
Dry Electrodes ◽  
Tendon Reflex ◽  
Dry Electrode

Abstract Wearable dry electrodes are needed for long-term biopotential recordings but are limited by their imperfect compliance with the skin, especially during body movements and sweat secretions, resulting in high interfacial impedance and motion artifacts. Herein, we report an intrinsically conductive polymer dry electrode with excellent self-adhesiveness, stretchability, and conductivity. It shows much lower skin-contact impedance and noise in static and dynamic measurement than the current dry electrodes and standard gel electrodes, enabling to acquire high-quality electrocardiogram (ECG), electromyogram (EMG) and electroencephalogram (EEG) signals in various conditions such as dry and wet skin and during body movement. Hence, this dry electrode can be used for long-term healthcare monitoring in complex daily conditions. We further investigated the capabilities of this electrode in a clinical setting and realized its ability to detect the arrhythmia features of atrial fibrillation accurately, and quantify muscle activity during deep tendon reflex testing and contraction against resistance.

scholarly journals A Long-Term, Portable ECG Patch Monitor Based on Flexible Dry Electrode

2022 ◽  
Author(s):  
Hao Chu ◽  
Chenxi Yang ◽  
Yantao Xing ◽  
Jianqing Li ◽  
Chengyu Liu
Keyword(s):  
Electrode Impedance ◽  
Ecg Monitoring ◽  
High Quality ◽  
Ecg Signals ◽  
Skin Electrode ◽  
Rr Interval ◽  
Dry Electrodes ◽  
Dry Electrode ◽  
And Storage

Abstract PurposeLong-term electrocardiogram (ECG) monitoring is an essential approach for the early diagnosis of cardiovascular diseases. Flexible dry electrodes that contains electrolyte without water could be a potential substitution of wet electrodes for long-term ECG monitoring. Therefore, this paper developes a long-term, portable ECG patch based on flexible dry electrodes, namely SEUECG-100.MethodA device consists of analog-front-end acquisition, data acquisition, and storage modules is developed and tested. An impedance test was conducted to compare the skin-electrode impedance of the flexible dry electrode and the Ag/AgCl wet electrode. The ECG signals were simutanously collected from the same subject using the SEUECG-100 and Shimmer device , which were then compared and analyzed from the perspective of ECG morphology, RR interval, and signal quality indices (SQI).ResultsThe experimental results reveal that the flexible dry electrode has the characteristics of low skin-electrode impedance. SEUECG-100 could collect high-quality ECG signals. The ECG signals collected by the two devices have a high RR interval correlation (r=0.999). SQI results show that SEUECG-100 is better than the Shimmer device in overcoming baseline drift. Long-term ECG acquisition and storage experiments show that SEUECG-100 could collect ECG signals with good stability and high reliability.ConclusionThe implementation of the proposed system design with dry electrodes could can effectively record long-term ECG monitoring with high quality in comparison to systems with wet electrodes from both impedance characteristics and signal morphology aspects.

Long-Term Inpatient Audiovisual Scalp EEG Monitoring

1999 ◽  
Vol 16 (2) ◽  
pp. 91-99 ◽  
Author(s):  
James L. Thompson ◽  
John S. Ebersole
Keyword(s):  
Eeg Monitoring ◽  
Scalp Eeg

Robust, self-adhesive, reinforced polymeric nanofilms enabling gas-permeable dry electrodes for long-term application

2021 ◽  
Vol 118 (38) ◽  
pp. e2111904118
Author(s):  
Yan Wang ◽  
Sunghoon Lee ◽  
Haoyang Wang ◽  
Zhi Jiang ◽  
Yasutoshi Jimbo ◽  
...  
Keyword(s):  
Human Skin ◽  
Continuous Monitoring ◽  
Signal To Noise Ratio ◽  
High Signal ◽  
Electrocardiogram Signals ◽  
Dry Electrodes ◽  
Dry Electrode ◽  
Soft Electronics ◽  
Adhesive Materials

Robust polymeric nanofilms can be used to construct gas-permeable soft electronics that can directly adhere to soft biological tissue for continuous, long-term biosignal monitoring. However, it is challenging to fabricate gas-permeable dry electrodes that can self-adhere to the human skin and retain their functionality for long-term (>1 d) health monitoring. We have succeeded in developing an extraordinarily robust, self-adhesive, gas-permeable nanofilm with a thickness of only 95 nm. It exhibits an extremely high skin adhesion energy per unit area of 159 μJ/cm2. The nanofilm can self-adhere to the human skin by van der Waals forces alone, for 1 wk, without any adhesive materials or tapes. The nanofilm is ultradurable, and it can support liquids that are 79,000 times heavier than its own weight with a tensile stress of 7.82 MPa. The advantageous features of its thinness, self-adhesiveness, and robustness enable a gas-permeable dry electrode comprising of a nanofilm and an Au layer, resulting in a continuous monitoring of electrocardiogram signals with a high signal-to-noise ratio (34 dB) for 1 wk.

scholarly journals A Dry Electrode Cap and Its Application in a Steady-State Visual Evoked Potential-Based Brain–Computer Interface

Electronics ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1080 ◽  
Author(s):  
Xiaoting Wu ◽  
Li Zheng ◽  
Lu Jiang ◽  
Xiaoshan Huang ◽  
Yuanyuan Liu ◽  
...  
Keyword(s):  
Visual Evoked Potential ◽  
Evoked Potential ◽  
Brain Computer Interface ◽  
Computer Interface ◽  
State Monitoring ◽  
Contact Impedance ◽  
Dry Electrodes ◽  
Dry Electrode ◽  
Electroencephalogram Eeg ◽  
The Brain

The wearable electroencephalogram (EEG) dry electrode acquisition system has shown great application prospects in mental state monitoring, the brain–computer interface (BCI), and other fields due to advantages such as being small in volume, light weight, and a ready-to-use facility. This study demonstrates a novel EEG cap with concise structure, easy adjustment size, as well as independently adjustable electrodes. The cap can be rapidly worn and adjusted in both horizontal and vertical dimensions. The dry electrodes on it can be adjusted independently to fit the scalp as quickly as possible. The accuracy of the BCI test employing this device is higher than when employing a headband. The proposed EEG cap makes adjustment easier and the contact impedance of the dry electrodes more uniform.

scholarly journals Ionic Liquid Regenerated Cellulose Membrane Electroless Plated By Silver Layer For ECG Signal Monitoring

2021 ◽  
Author(s):  
Xueli Fu ◽  
Yanping Wang ◽  
Wei Wang ◽  
Dan Yu
Keyword(s):  
Ionic Liquid ◽  
Skin Irritation ◽  
Regenerated Cellulose ◽  
Cellulose Membrane ◽  
Ecg Signal ◽  
Contact Impedance ◽  
Skin Contact ◽  
Dry Electrode ◽  
Wide Range

Abstract Flexible electrodes have attracted the interest of a wide range of people because they can monitor human health signals like ECG, EMG and EEG as wearable devices. However, PDMS-based membrane electrodes have the problem of difficulty in depositing metal layers, while fabric electrodes have high contact impedance. Furthermore, the widely used Ag/AgCl electrodes have the shortcomings of skin inflammation or skin irritation. Therefore, we fabricate a skin-like electrical conductive electrode via electroless silver plating on the surface of regenerated cellulose membrane, in which the cellulose membrane is obtained by the dissolution of cotton fiber with green solvent ionic liquid [Bmim]Cl. The as-prepared biocompatible electrode with low skin-electrode contact impedance can be used as a dry electrode for a long-term period of use. The impedance at 700 Hz is only 8 kΩ/cm2, and the conductivity can reach 252 s/cm. After 5 hours of wear, the skin contact impedance of the electrode was only 10 kΩ/cm2 under 700 Hz(when AgNO3 was used at a concentration of 0.20 mol/L). Importantly, the electrodes not only provide a stable and clear ECG signal, but also offer a high level of comfort and low impedance, when used for long-term health monitoring.

Routine EEG and Temporal Lobe Epilepsy: Relation to Long-Term EEG Monitoring, Quantitative MRI, and Operative Outcome

Epilepsia ◽  
1996 ◽  
Vol 37 (7) ◽  
pp. 651-656 ◽  
Author(s):  
Gregory D. Cascino ◽  
Max R. Trenerry ◽  
Elson L. So ◽  
Frank W. Sharbrough ◽  
Cheolsu Shin ◽  
...  
Keyword(s):  
Temporal Lobe Epilepsy ◽  
Temporal Lobe ◽  
Quantitative Mri ◽  
Eeg Monitoring ◽  
Operative Outcome

scholarly journals Textile Electrodes: Influence of Knitting Construction and Pressure on the Contact Impedance

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1578
Author(s):  
Luisa Euler ◽  
Li Guo ◽  
Nils-Krister Persson
Keyword(s):  
Smooth Surface ◽  
Research Field ◽  
Uneven Surface ◽  
Contact Impedance ◽  
Dry Electrodes ◽  
Textile Electrodes ◽  
Human Forearm ◽  
Wet Condition ◽  
Electrode Contact ◽  
Influencing Parameters

Textile electrodes, also called textrodes, for biosignal monitoring as well as electrostimulation are central for the emerging research field of smart textiles. However, so far, only the general suitability of textrodes for those areas was investigated, while the influencing parameters on the contact impedance related to the electrode construction and external factors remain rather unknown. Therefore, in this work, six different knitted electrodes, applied both wet and dry, were compared regarding the influence of specific knitting construction parameters on the three-electrode contact impedance measured on a human forearm. Additionally, the influence of applying pressure was investigated in a two-electrode setup using a water-based agar dummy. Further, simulation of an equivalent circuit was used for quantitative evaluation. Indications were found that the preferred electrode construction to achieve the lowest contact impedance includes a square shaped electrode, knitted with a high yarn density and, in the case of dry electrodes, an uneven surface topography consisting of loops, while in wet condition a smooth surface is favorable. Wet electrodes are showing a greatly reduced contact impedance and are therefore to be preferred over dry ones; however, opportunities are seen for improving the electrode performance of dry electrodes by applying pressure to the system, thereby avoiding disadvantages of wet electrodes with fluid administration, drying-out of the electrolyte, and discomfort arising from a “wet feeling”.

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