scholarly journals The Arch Electrode: A Novel Dry Electrode Concept for Improved Wearing Comfort

2021 ◽  
Vol 15 ◽  
Author(s):  
Beatriz Vasconcelos ◽  
Patrique Fiedler ◽  
René Machts ◽  
Jens Haueisen ◽  
Carlos Fonseca
Keyword(s):  
Silver Chloride ◽  
Thermoplastic Polyurethane ◽  
Substrate Material ◽  
The Novel ◽  
Dry Electrodes ◽  
Signal Characteristics ◽  
Dry Electrode ◽  
Dry Contact ◽  
Silver Silver

Electroencephalography (EEG) is increasingly used for repetitive and prolonged applications like neurofeedback, brain computer interfacing, and long-term intermittent monitoring. Dry-contact electrodes enable rapid self-application. A common drawback of existing dry electrodes is the limited wearing comfort during prolonged application. We propose a novel dry Arch electrode. Five semi-circular arches are arranged parallelly on a common baseplate. The electrode substrate material is a flexible thermoplastic polyurethane (TPU) produced by additive manufacturing. A chemical coating of Silver/Silver-Chloride (Ag/AgCl) is applied by electroless plating using a novel surface functionalization method. Arch electrodes were manufactured and validated in terms of mechanical durability, electrochemical stability, in vivo applicability, and signal characteristics. We compare the results of the dry arch electrodes with dry pin-shaped and conventional gel-based electrodes. 21-channel EEG recordings were acquired on 10 male and 5 female volunteers. The tests included resting state EEG, alpha activity, and a visual evoked potential. Wearing comfort was rated by the subjects directly after application, as well as at 30 min and 60 min of wearing. Our results show that the novel plating technique provides a well-adhering electrically conductive and electrochemically stable coating, withstanding repetitive strain and bending tests. The signal quality of the Arch electrodes is comparable to pin-shaped dry electrodes. The average channel reliability of the Arch electrode setup was 91.9 ± 9.5%. No considerable differences in signal characteristics have been observed for the gel-based, dry pin-shaped, and arch-shaped electrodes after the identification and exclusion of bad channels. The comfort was improved in comparison to pin-shaped electrodes and enabled applications of over 60 min duration. Arch electrodes required individual adaptation of the electrodes to the orientation and hairstyle of the volunteers. This initial preparation time of the 21-channel cap increased from an average of 5 min for pin-like electrodes to 15 min for Arch electrodes and 22 min for gel-based electrodes. However, when re-applying the arch electrode cap on the same volunteer, preparation times of pin-shaped and arch-shaped electrodes were comparable. In summary, our results indicate the applicability of the novel Arch electrode and coating for EEG acquisition. The novel electrode enables increased comfort for prolonged dry-contact measurement.

scholarly journals Comparison of three types of dry electrodes for electroencephalography

ACTA IMEKO ◽  
2014 ◽  
Vol 3 (3) ◽  
pp. 33 ◽  
Author(s):  
Patrique Fiedler ◽  
Jens Haueisen ◽  
Dunja Jannek ◽  
Stefan Griebel ◽  
Lena Zentner ◽  
...  
Keyword(s):  
Printed Circuit Boards ◽  
Silver Chloride ◽  
Measurement Range ◽  
Open Circuit ◽  
Signal Acquisition ◽  
The Novel ◽  
Dry Electrodes ◽  
Dry Electrode ◽  
Silver Silver ◽  
Silver Silver Chloride

A potential new area of routine application for electroencephalography (EEG) is the brain-computer interface, which might enable disabled people to interact with their environment, based on measured brain signals. However, conventional electroencephalography is not suitable here due to limitations arising from complicated, time-consuming and error-prone preparation. Recently, several approaches for dry electrodes have been proposed. Our aim is the comparison and assessment of three types of dry electrodes and standard wet silver/silver-chloride electrodes for EEG signal acquisition. We developed novel EEG electrodes with titanium and polyurethane as base materials, which were coated with nanometer sized titanium-nitride films. Furthermore gold multi-pin electrodes were arranged on printed circuit boards. The results of the comparison of these electrodes with conventional wet silver/silver-chloride electrodes in terms of electrode impedances are presented, as well as open circuit potentials and biosignal measurements. Impedances were significantly higher for all dry electrode types compared to wet electrodes, but still within the measurement range of today’s standard biosignal amplifiers. It was found that the novel dry titanium and polyurethane based electrodes show biosignal quality equivalent to conventional electrodes. In conclusion, the novel dry electrodes seem to be suitable for application in brain-machine interfaces.

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 Dry Electrodes for Surface Electromyography Based on Architectured Titanium Thin Films

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2135 ◽  
Author(s):  
Marco S. Rodrigues ◽  
Patrique Fiedler ◽  
Nora Küchler ◽  
Rui P. Domingues ◽  
Cláudia Lopes ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Surface Electromyography ◽  
Silver Chloride ◽  
Thermoplastic Polyurethane ◽  
Skin Irritation ◽  
Normal Growth ◽  
Quality Parameters ◽  
Skin Impedance ◽  
Dry Electrodes

Electrodes of silver/silver chloride (Ag/AgCl) are dominant in clinical settings for surface electromyography (sEMG) recordings. These electrodes need a conductive electrolyte gel to ensure proper performance, which dries during long-term measurements inhibiting the immediate electrode’s reuse and is often linked to skin irritation episodes. To overcome these drawbacks, a new type of dry electrodes based on architectured titanium (Ti) thin films were proposed in this work. The architectured microstructures were zigzags, obtained with different sputtering incidence angles (α), which have been shown to directly influence the films’ porosity and electrical conductivity. The electrodes were prepared using thermoplastic polyurethane (TPU) and stainless-steel (SS) substrates, and their performance was tested in male volunteers (athletes) by recording electromyography (EMG) signals, preceded by electrode-skin impedance measurements. In general, the results showed that both SS and TPU dry electrodes can be used for sEMG recordings. While SS electrodes almost match the signal quality parameters of reference electrodes of Ag/AgCl, the performance of electrodes based on TPU functionalized with a Ti thin film still requires further improvements. Noteworthy was the clear increase of the signal to noise ratios when the thin films’ microstructure evolved from normal growth towards zigzag microstructures, meaning that further tailoring of the thin film microstructure is a possible route to achieve optimized performances. Finally, the developed dry electrodes are reusable and allow for multiple EMG recordings without being replaced.

scholarly journals Properties of different types of dry electrodes for wearable smart monitoring devices

2020 ◽  
Vol 65 (4) ◽  
pp. 405-415
Author(s):  
Lana Popović-Maneski ◽  
Marija D. Ivanović ◽  
Vladimir Atanasoski ◽  
Marjan Miletić ◽  
Sanja Zdolšek ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Heart Muscle ◽  
Silver Chloride ◽  
Real Life ◽  
Motion Artifacts ◽  
The Body ◽  
Stainless Steel Electrode ◽  
Steel Electrode ◽  
Dry Electrodes ◽  
Dry Electrode

AbstractWearable smart monitors (WSMs) applied for the estimation of electrophysiological signals are of utmost interest for a non-stressed life. WSM which records heart muscle activities could signalize timely a life-threatening event. The heart muscle activities are typically recorded across the heart at the surface of the body; hence, a WSM monitor requires high-quality surface electrodes. The electrodes used in the clinical settings [i.e. silver/silver chloride (Ag/AgCl) with the gel] are not practical for the daily out of clinic usage. A practical WSM requires the application of a dry electrode with stable and reproducible electrical characteristics. We compared the characteristics of six types of dry electrodes and one gelled electrode during short-term recordings sessions (≈30 s) in real-life conditions: Orbital, monolithic polymer plated with Ag/AgCl, and five rectangular shaped 10 × 6 × 2 mm electrodes (Orbital, Ag electrode, Ag/AgCl electrode, gold electrode and stainless-steel AISI304). The results of a well-controlled analysis which considered motion artifacts, line noise and junction potentials suggest that among the dry electrodes Ag/AgCl performs the best. The Ag/AgCl electrode is in average three times better compared with the stainless-steel electrode often used in WSMs.

Soft Dry Electrodes for Electrocardiogram with Conductive Silver Nanowires

2014 ◽  
Vol 1685 ◽  
Author(s):  
Amanda Myers ◽  
Yong Zhu
Keyword(s):  
Health Monitoring ◽  
Silver Chloride ◽  
Silver Nanowires ◽  
Skin Irritation ◽  
Hospital Setting ◽  
Skin Impedance ◽  
Ecg Signals ◽  
Dry Electrode ◽  
Silver Silver

ABSTRACTWith increasing attention towards long-term health monitoring, there is a pressing need to create noninvasive sensors that monitor vital bioelectronic signals. Particular importance is placed on measuring electrocardiogram (ECG) signals as heart issues are widespread and can be prevented with the proper warning and care of potential problems. Currently, ECGs are taken in a hospital setting using disposable silver-silver chloride (Ag/AgCl) pre-gelled electrodes. Unfortunately, this cannot translate to a long-term monitoring setting due to the electrolytic gel of the electrodes drying and causing skin irritation. This paper presents a soft, skin-mountable dry electrode based on silver nanowires (AgNWs) for measuring ECG signals that can be used in long-term, wearable health monitoring due to the elimination of the electrolytic gel. The AgNWs are embedded in polydimethylsiloxane (PDMS), which creates a robust design that will not suffer from delamination or cracking problems that can eventually lead to loss of conductivity. The electrode is characterized by electrode-skin impedance as a function of frequency and by the surface resistance as the electrode is stretched. The performance of the dry electrode is evaluated and comparable to that of conventional Ag/AgCl electrodes. The ability of the dry electrode to conform to skin is believed to compensate for the lack of an electrolytic gel.

scholarly journals Characterization of Ag/AgCl Dry Electrodes for Wearable Electrophysiological Sensing

2022 ◽  
Vol 2 ◽  
Author(s):  
Min Suk Lee ◽  
Akshay Paul ◽  
Yuchen Xu ◽  
W. David Hairston ◽  
Gert Cauwenberghs
Keyword(s):  
Electrochemical Impedance ◽  
Silver Chloride ◽  
Low Cost ◽  
The Body ◽  
Clinical Environment ◽  
Electrical Stability ◽  
Dry Electrodes ◽  
Auditory Steady State Response ◽  
Silver Silver ◽  
Silver Silver Chloride

With the rising need for on-body biometric sensing, the development of wearable electrophysiological sensors has been faster than ever. Surface electrodes placed on the skin need to be robust in order to measure biopotentials from the body reliably and comfortable for extended wearability. The electrical stability of nonpolarizable silver/silver chloride (Ag/AgCl) and its low-cost, commercial production have made these electrodes ubiquitous health sensors in the clinical environment, where wet gels and long wires are accommodated by patient immobility. However, smaller, dry electrodes with wireless acquisition are essential for truly wearable, continuous health sensing. Currently, techniques for the robust fabrication of custom Ag/AgCl electrodes are lacking. Here, we present three methods for the fabrication of Ag/AgCl electrodes: oxidizing Ag in a chlorine solution, electroplating Ag, and curing Ag/AgCl ink. Each of these methods is then used to create three different electrode shapes for wearable application. Bench-top and on-body evaluation of the electrode techniques was achieved by electrochemical impedance spectroscopy (EIS), calculation of variance in electrocardiogram (ECG) measurements, and analysis of auditory steady-state response (ASSR) measurement. Microstructures produced on the electrode by each fabrication technique were also investigated with scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). The custom Ag/AgCl electrodes were found to be efficient in comparison with standard, commercial Ag/AgCl wet electrodes across all three of our presented techniques, with Ag/AgCl ink shown to be the better out of the three in bench-top and biometric recordings.

Electrode for recording direction of activation, conduction velocity, and monophasic action potential of myocardium

1997 ◽  
Vol 272 (4) ◽  
pp. H1917-H1927 ◽  
Author(s):  
S. M. Horner ◽  
Z. Vespalcova ◽  
M. J. Lab
Keyword(s):  
Action Potential ◽  
Conduction Velocity ◽  
Simultaneous Measurement ◽  
Silver Chloride ◽  
Reference Electrode ◽  
Simultaneous Recording ◽  
Monophasic Action Potential ◽  
Time Of Arrival ◽  
Silver Silver

Conduction velocity and recovery of excitability are central facets of reentry arrhythmias, and yet there are no satisfactory techniques for the simultaneous measurement of both from the same area of myocardium. We have developed an electrode arrangement that allows the simultaneous recording of conduction velocity, repolarization of the myocardium together with an index of dispersion, and direction of activation of the myocardium. Three silver/silver chloride electrodes were arranged in an equilateral triangle with a reference electrode at the center. From this arrangement three monophasic action potentials were recorded. From the time of arrival of the wavefront of activation at each electrode the direction of activation and conduction velocity were calculated in real time by a computer. There was a good correlation for the in vivo signals from the circular electrode and the new electrode both for conduction velocity (r = 0.99, P < 0.001) and for direction of activation (r = 0.99, P < 0.001). This new mathematical method and electrode design allows the simultaneous measurement of conduction velocity and direction and monophasic action potential, and this can give a beat-by-beat indication of wavelength and dispersion of action potential duration.

scholarly journals Performance evaluation of a new 3D printed dry-contact electrode for EEG signals measurement

2021 ◽  
Vol 24 (1) ◽  
pp. 287
Author(s):  
Aaisha Diaa-Aldeen Abdullah ◽  
Auns Q. Al-Neami
Keyword(s):  
Correlation Coefficient ◽  
Silver Chloride ◽  
Signal To Noise Ratio ◽  
Skin Impedance ◽  
Impedance Change ◽  
Eeg Signals ◽  
Dry Electrode ◽  
Dry Contact ◽  
3D Printed ◽  
Contact Electrode

Traditional wet silver/silver chloride electrodes are used to record electroencephalography (EEG) signals mainly because of their potential repeatability, excellent signal to noise ratio and biocompatibility. This type of electrode is only suitable for conductive glue, which can irritate the skin and cause injury. In addition, as time goes the conductive gel will be dehydrated so the quality of the EEG signal will decrease. To overcome these problems, 3D printed dry-contact electrodes with multi-pins are designed in this work to measure brain signals without prior preparation or gel application. 3D printed electrodes are made from polylactic acids polymer and coated with suitable materials to enhance the conductivity. Electrode-scalp impedance on human was also measured. To evaluate the dry-contact electrode, EEG measurement are performed in subjects and compared with EEG signals acquired by wet electrode by using linear correlation coefficient. Experimentally results showed that the average electrode-skin impedance change of dry electrode in frontal site (9.42-7.25KΩ) and in occipital site (9.56-8.66KΩ). The correlation coefficient between dry and wet electrodes in frontal site (91.4%) and in occipital site (80%). To conclude, the 3D printed dry-contact electrode can be will promising applied on hairy site and provide a promising solutions for long-term monitoring EEG.

Role of venular endothelium in control of arteriolar diameter during functional hyperemia

1994 ◽  
Vol 267 (3) ◽  
pp. H1227-H1231 ◽  
Author(s):  
Y. Saito ◽  
A. Eraslan ◽  
V. Lockard ◽  
R. L. Hester
Keyword(s):  
Silver Chloride ◽  
Muscle Stimulation ◽  
Functional Hyperemia ◽  
Cremaster Muscle ◽  
Silver Silver ◽  
Silver Silver Chloride ◽  
Arteriolar Vasodilation ◽  
Venular Endothelium

This study was designed to determine the importance of the venular endothelium in the vasodilation of adjacent arterioles during functional hyperemia. The hamster cremaster muscle was prepared for in vivo microscopy. Two silver-silver chloride electrodes were placed across the pedicle of the cremaster muscle, and a square-wave pulse (10 V amplitude, 1 ms duration, and 1 Hz frequency) was used to elicit muscle contraction. Muscle stimulation for 1 min resulted in a vasodilation of the first-order arterioles from 74 +/- 2 to 91 +/- 2 microns (n = 9, P < 0.05). After perfusion of the venule with air to disrupt the venular endothelium, there was no significant effect on the resting diameter, 73 +/- 3 microns, but the vasodilation associated with the muscle stimulation was significantly attenuated to 82 +/- 3 microns (P < 0.01). After completion of these experiments, the disruption of venular endothelium was confirmed by electron microscopy. The functional vasodilation of arterioles adjacent to venules with an intact endothelium (venules in which air did not enter) was retained after air perfusion (n = 6). These results suggest that the presence of the venular endothelium is important for the arteriolar vasodilation during functional hyperemia. We propose that the venular endothelium releases a relaxing factor responsible for a portion of the functional arteriolar vasodilation.

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