Hair-contact sensors offer potential medical, behavioral applications.
Every technology has its shortcomings and electroencephalography (EEG) is no exception.
What is EEG, you ask? It’s a method to measure brain activity via sensors attached to a person’s scalp. It’s most commonly used to diagnose neurological conditions like epilepsy. As handy as this tech is, however, it involves complex setups that are severely limited in portability.
It’s been a long time in the making, but there might just be an answer to this problem.
Tracking Brain Activity with Untethered EEG
The wearable EEG system can track brain activity during movement. (Image courtesy of Jacobs School of Engineering/UC San Diego.)
EEG is typically limited to state-of-the-art equipment confined to a research lab. Sensors measure brain waves and then relay measurements to software that tracks and identifies irregularities.
However, in the case of epilepsy, a laboratory environment is far from ideal. Seizures don’t usually happen when a person is conveniently hooked up to an EEG.
This is where the new portable system comes in. Reminiscent of a rugby helmet, it is a wearable brain activity monitoring system that uses dry sensors to take high-density electroencephalographic measurements. Its octopus-like elastic arms are designed to fit a range of head sizes and each arm is outfitted with its own sensor.
Although it still can’t handle vigorous movement like running, the system is capable of taking measurements while a subject is walking.
Dry Run
EEG typically uses wet sensors to take its measurements, but these are difficult to apply outside of a lab setting. These sensors require the application of conductive gel, which is a bit unfortunate if you like your hair where it is, thank you very much.
To combat this issue, the bioengineers and cognitive scientists at the University of California San Diego had to get a little creative. They developed two types of dry sensors, both of which can be applied directly without conductive gel:
- Hair-contact sensors are made of a combination of silver and carbon on a flexible substrate. A silver and silver-chloride coating on the ends allows the sensor to conduct through hair.
- Skin-contact sensors are made from a hydrogel encased in a conductive membrane.
Mapping the Brain’s Network
Measurements from the system’s sensors are transferred to an algorithm that separates brain signals from noise. To identify irregularities, it splits data into statistically unrelated components and compares these with clean data obtained while the subject is resting.
Hair-contact dry sensors use a special silver/carbon compound that took researchers four years to develop. (Image courtesy of Jacobs School of Engineering/UC San Diego.)
This algorithm also takes information about the brain’s known anatomy and compares it with EEG data in order to locate signal points of origin. With these findings the researchers then used machine learning to correlate specific brain network patterns with cognitive and behavioral events.
The Future of Brain Wave Monitoring
It might not be the fashion statement you want to make out in public, but this technology holds a lot of promise.
“We will be able to prompt the brain to fix its own problems,” said Gert Cauwenberghs, professor of bioengineering at UCSD’s Jacobs School of Engineering and Institute for Neural Computation. “We are trying to get away from invasive technologies such as deep brain stimulation and prescription medications and instead start up a repair process by using the brain’s synaptic plasticity.”
As it develops, the portable EEG system could be employed on a large scale – even to the point where it could eventually be connected to smartphones.
Yes, that’s right: someday, your phone might be able to read your mind.
For more information about the project, you can check out this page or read the full paper here.
