A Flexible, Robust, and Gel-Free Electroencephalogram Electrode for Noninvasive Brain-Computer Interfaces

Area of Science:

• Biomedical Engineering
• Materials Science
• Neuroscience

Background:

• Noninvasive brain-computer interfaces (BCIs) face challenges with hair interfering with electrode contact.
• Conductive gels used with conventional electrodes can be inconvenient and complicated.

Purpose of the Study:

• To develop a cost-effective, gel-free electrode for electroencephalogram (EEG) that bypasses hair.
• To evaluate the performance of the new electrode on both hairless and hairy skin.

Main Methods:

• Fabrication of a flexible, gel-free electrode using silver nanowires, polyvinyl butyral, and melamine sponge (AgPMS).
• Assessment of electrode conductivity, mechanical stability, and hair-bypassing capability.
• Testing BCI accuracy using steady-state visual evoked potential (SSVEP) on hairless and hairy skin.

Main Results:

• The AgPMS electrode exhibits high conductivity (917 S/m) and remarkable mechanical stability.
• BCI accuracy with the AgPMS electrode on hairless skin (86%) is comparable to gel-based electrodes (88%).
• Performance on hairy skin was not significantly reduced, demonstrating effective hair-bypassing.

Conclusions:

• The developed AgPMS electrode offers a robust, gel-free solution for noninvasive BCIs.
• This new electrode can replace conventional ones for both hairless and hairy skin EEG applications.
• The findings pave the way for more accessible and user-friendly BCI technology.