The device also uses a 3D-printable bioadhesive ink that allows the electrode to stick directly onto the scalp without the need for any gloopy gels or other skin preparation. This minimizes the gap between the electrode and scalp, improving the signal quality. The lightweight, flexible and stretchable nature of the device also means that the device stays put — even when combing hair and donning and removing a baseball cap — and can be worn for longer periods of time, making it suitable for chronic monitoring.
The team found that the new device performed comparably to gold electrodes, the current standard electrodes used for EEG. However, the hairlike electrode maintained better contact between the electrode and skin and performed reliably for over 24 hours of continuous wear without any degradation in signal quality. Because the electrodes don’t have to be removed and replaced like traditional EEG monitoring systems, they eliminate the risk of inconsistent data, even across different monitoring sessions.
“You don’t have to worry if the position of the electrode has changed or if the impedance has changed because the electrodes haven’t moved,” Zhou said.
Unlike the traditional metal electrodes, the new electrodes mimic human hair and are inconspicuous on the head. Since the device is 3D-printed, Zhou explained that they can print the electrode in different colors to match a person’s hair, too.
“This makes it discreet, and people may be more comfortable wearing this, especially if they require continuous EEG monitoring and need to wear the electrodes for an extended period of time,” Zhou said.
Currently, the EEG is still wired; patients need to be connected to a machine while their brain activity is recorded. In the future, the researchers hope to make the system wireless so that people can move around more freely during recording sessions.
Other Penn State authors on the paper include lead authors Salahuddin Ahmed and Marzia Momin, both doctoral students in the Department of Engineering Science and Mechanics. Jiashu Ren, doctoral student in the Department of Engineering Science and Mechanics; Hyunjin Lee, doctoral student in the Department of Biomedical Engineering; Li-Pang Huang, research assistant; and Basma AlMahmood, undergraduate student in the Department of Physics also contributed to the paper.
Other authors include Chi-Ching Kuo, Archana Pandiyan and Loganathan Veeramuthu from the Department of Molecular Science and Engineering, National Taipei University of Technology.
Funding from the National Institutes of Health; Oak Ridge Associated Universities; the National Taipei University of Technology-Penn State Collaborative Seed Grant Program; and the Department of Engineering Science and Mechanics, the Materials Research Institute and the Huck Institutes of Life Sciences at Penn State supported this work.