We may be seeing advances in brain-machine interfaces, but the electrodes that are used to detect users' brain activity are still pretty messy. Chinese scientists have decided to do something about it, by developing gel-free electrodes that work through hair.
Ordinarily, when someone is utilizing a system that allows them to control a computer or other device via their thoughts, they need to have multiple electrodes attached to their scalp. These detect electrical activity within the brain, but in order to make a good connection, they have to be coated with a conductive gel. Even then, the user's hair may still cause interference, and the gel can be difficult to subsequently wash out.
Seeking to create an alternative, a team from Beijing's Tsinghua University has produced cheap, flexible, conformable electrodes by placing conductive silver nanowires within ordinary melamine sponge material.
When a skull cap containing 10 of these electrodes was tested on volunteers, it was found that the devices could detect brain activity on shaved heads with just as much accuracy as conventional electrodes. Unlike the regular ones, though, the sponge electrodes performed equally well when sensing electrical activity through a full head of hair – and no gel was required. They're also said to not be adversely affected by heat or sweat.
In a demonstration of the technology, a female test subject (who did not have a shaved head) successfully used the electrode cap to control a toy car using her brain waves.
A paper on the research was recently published in the journal Nano Letters.
Source: American Chemical Society
