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

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...

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Main Authors: Beatriz Vasconcelos, Patrique Fiedler, René Machts, Jens Haueisen, Carlos Fonseca
Format: Article
Language:English
Published: Frontiers Media S.A. 2021-10-01
Series:Frontiers in Neuroscience
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fnins.2021.748100/full
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author Beatriz Vasconcelos
Beatriz Vasconcelos
Patrique Fiedler
René Machts
Jens Haueisen
Jens Haueisen
Carlos Fonseca
Carlos Fonseca
author_facet Beatriz Vasconcelos
Beatriz Vasconcelos
Patrique Fiedler
René Machts
Jens Haueisen
Jens Haueisen
Carlos Fonseca
Carlos Fonseca
author_sort Beatriz Vasconcelos
collection DOAJ
description 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.
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spelling doaj.art-ecb1567bff4446c6809e48f24ed276a92022-12-21T19:16:03ZengFrontiers Media S.A.Frontiers in Neuroscience1662-453X2021-10-011510.3389/fnins.2021.748100748100The Arch Electrode: A Novel Dry Electrode Concept for Improved Wearing ComfortBeatriz Vasconcelos0Beatriz Vasconcelos1Patrique Fiedler2René Machts3Jens Haueisen4Jens Haueisen5Carlos Fonseca6Carlos Fonseca7Departamento de Engenharia Metalúrgica e de Materiais, Faculdade de Engenharia, Universidade do Porto, Porto, PortugalCEMUC – Department of Mechanical Engineering, University of Coimbra, Coimbra, PortugalInstitute of Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, GermanyInstitute of Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, GermanyInstitute of Biomedical Engineering and Informatics, Technische Universität Ilmenau, Ilmenau, GermanyDepartment of Neurology, Biomagnetic Center, Jena University Hospital, Jena, GermanyDepartamento de Engenharia Metalúrgica e de Materiais, Faculdade de Engenharia, Universidade do Porto, Porto, PortugalLAETA/INEGI, Institute of Science and Innovation in Mechanical and Industrial Engineering, Porto, PortugalElectroencephalography (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.https://www.frontiersin.org/articles/10.3389/fnins.2021.748100/fullbiopotential measurementelectrodesbiosignalselectroencephalographyelectrode-skin impedanceadditive manufacturing
spellingShingle Beatriz Vasconcelos
Beatriz Vasconcelos
Patrique Fiedler
René Machts
Jens Haueisen
Jens Haueisen
Carlos Fonseca
Carlos Fonseca
The Arch Electrode: A Novel Dry Electrode Concept for Improved Wearing Comfort
Frontiers in Neuroscience
biopotential measurement
electrodes
biosignals
electroencephalography
electrode-skin impedance
additive manufacturing
title The Arch Electrode: A Novel Dry Electrode Concept for Improved Wearing Comfort
title_full The Arch Electrode: A Novel Dry Electrode Concept for Improved Wearing Comfort
title_fullStr The Arch Electrode: A Novel Dry Electrode Concept for Improved Wearing Comfort
title_full_unstemmed The Arch Electrode: A Novel Dry Electrode Concept for Improved Wearing Comfort
title_short The Arch Electrode: A Novel Dry Electrode Concept for Improved Wearing Comfort
title_sort arch electrode a novel dry electrode concept for improved wearing comfort
topic biopotential measurement
electrodes
biosignals
electroencephalography
electrode-skin impedance
additive manufacturing
url https://www.frontiersin.org/articles/10.3389/fnins.2021.748100/full
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