Flexible Multi-Layer Semi-Dry Electrode for Scalp EEG Measurements at Hairy Sites
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...
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MDPI AG
2019-08-01
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| Series: | Micromachines |
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| Online Access: | https://www.mdpi.com/2072-666X/10/8/518 |
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| author | Haoqiang Hua Wei Tang Xiangmin Xu David Dagan Feng Lin Shu |
| author_facet | Haoqiang Hua Wei Tang Xiangmin Xu David Dagan Feng Lin Shu |
| author_sort | Haoqiang Hua |
| collection | DOAJ |
| description | 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. |
| first_indexed | 2024-04-13T03:00:53Z |
| format | Article |
| id | doaj.art-64322ed4f1494d3ca8b4f68df232bbbb |
| institution | Directory Open Access Journal |
| issn | 2072-666X |
| language | English |
| last_indexed | 2024-04-13T03:00:53Z |
| publishDate | 2019-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Micromachines |
| spelling | doaj.art-64322ed4f1494d3ca8b4f68df232bbbb2022-12-22T03:05:26ZengMDPI AGMicromachines2072-666X2019-08-0110851810.3390/mi10080518mi10080518Flexible Multi-Layer Semi-Dry Electrode for Scalp EEG Measurements at Hairy SitesHaoqiang Hua0Wei Tang1Xiangmin Xu2David Dagan Feng3Lin Shu4School of Electronic and Information Engineering, South China University of Technology, Guangzhou 510641, ChinaSchool of Electronic and Information Engineering, South China University of Technology, Guangzhou 510641, ChinaSchool of Electronic and Information Engineering, South China University of Technology, Guangzhou 510641, ChinaSchool of Computer Science, The University of Sydney, Sydney 2006, AustraliaSchool of Electronic and Information Engineering, South China University of Technology, Guangzhou 510641, ChinaOne 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.https://www.mdpi.com/2072-666X/10/8/518EEGsemi-dry electrodeflexible electrodemulti-layer |
| spellingShingle | Haoqiang Hua Wei Tang Xiangmin Xu David Dagan Feng Lin Shu Flexible Multi-Layer Semi-Dry Electrode for Scalp EEG Measurements at Hairy Sites Micromachines EEG semi-dry electrode flexible electrode multi-layer |
| title | Flexible Multi-Layer Semi-Dry Electrode for Scalp EEG Measurements at Hairy Sites |
| title_full | Flexible Multi-Layer Semi-Dry Electrode for Scalp EEG Measurements at Hairy Sites |
| title_fullStr | Flexible Multi-Layer Semi-Dry Electrode for Scalp EEG Measurements at Hairy Sites |
| title_full_unstemmed | Flexible Multi-Layer Semi-Dry Electrode for Scalp EEG Measurements at Hairy Sites |
| title_short | Flexible Multi-Layer Semi-Dry Electrode for Scalp EEG Measurements at Hairy Sites |
| title_sort | flexible multi layer semi dry electrode for scalp eeg measurements at hairy sites |
| topic | EEG semi-dry electrode flexible electrode multi-layer |
| url | https://www.mdpi.com/2072-666X/10/8/518 |
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