Electrochemical and structural characterization of nanocomposite Agy:TiNx thin films for dry bioelectrodes: the effect of the N/Ti ratio and Ag content

Pedrosa, Paulo; Machado, Diogo; Fiedler, Patrique; Alves, E.; Haueisen, Jens; Vaz, F.; Fonseca, C.

doi:10.1016/j.electacta.2014.12.020

Cited by 9 publications

(2 citation statements)

References 51 publications

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“…1). For frequencies below 66 Hz there is a phase shift and the impedance starts to increase, being an indication that the measured impedance receives a capacitive contribution, coming from interfacial charge accumulation at the interface ( Pedrosa et al, 2015 ). However, the impedance remains below 100 Ω throughout the investigated frequency band, even for the lowest investigated frequency of 66 mHz, thanks to the very large interfacial area displayed by the AgCl layer.…”

Section: Resultsmentioning

confidence: 99%

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

et al. 2021

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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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Section: Resultsmentioning

confidence: 99%

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

et al. 2021

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“…The centerto-center distances of the pins are 2.5 mm. The design is an improved version of our previously presented multipin electrodes (Fiedler et al 2014;Pedrosa et al 2015a).…”

Section: Dry Electrodesmentioning

confidence: 99%

Novel Multipin Electrode Cap System for Dry Electroencephalography

et al. 2015

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Current usage of electroencephalography (EEG) is limited to laboratory environments. Self-application of a multichannel wet EEG caps is practically impossible, since the application of state-of-the-art wet EEG sensors requires trained laboratory staff. We propose a novel EEG cap system with multipin dry electrodes overcoming this problem. We describe the design of a novel 24-pin dry electrode made from polyurethane and coated with Ag/AgCl. A textile cap system holds 97 of these dry electrodes. An EEG study with 20 volunteers compares the 97-channel dry EEG cap with a conventional 128-channel wet EEG cap for resting state EEG, alpha activity, eye blink artifacts and checkerboard pattern reversal visual evoked potentials. All volunteers report a good cap fit and good wearing comfort. Average impedances are below 150 kΩ for 92 out of 97 dry electrodes, enabling recording with standard EEG amplifiers. No significant differences are observed between wet and dry power spectral densities for all EEG bands. No significant differences are observed between the wet and dry global field power time courses of visual evoked potentials. The 2D interpolated topographic maps show significant differences of 3.52 and 0.44% of the map areas for the N75 and N145 VEP components, respectively. For the P100 component, no significant differences are observed. Dry multipin electrodes integrated in a textile EEG cap overcome the principle limitations of wet electrodes, allow rapid application of EEG multichannel caps by non-trained persons, and thus enable new fields of application for multichannel EEG acquisition.

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Electro- and Magnetoencephalographic Measurements

Knösche

Haueisen

2022

EEG/MEG Source Reconstruction

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Electrochemical and structural characterization of nanocomposite Agy:TiNx thin films for dry bioelectrodes: the effect of the N/Ti ratio and Ag content

Cited by 9 publications

References 51 publications

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

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

Novel Multipin Electrode Cap System for Dry Electroencephalography

Electro- and Magnetoencephalographic Measurements

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