Most people who have driven down a lonely, straight road late at night knows what it feels like to get drowsy while driving, and how difficult it can become to stay awake. Drivers are often cautioned with bright highway signs to take break if they are feeling fatigued, because tired drivers are very impaired drivers. But scientists are trying to develop a new way to alleviate fatigue on the road, or create a tool for people who work with heavy equipment that can be dangerous when operators are distracted or tired. A new approach involves earbuds that can detect symptoms of drowsiness in the brain.
A new type of special earbuds can work like a miniature electroencephalogram (EEG), which measures electrical activity in the brain. Usually, EEGs rely on electrodes that are attached to the head to take measurements. But the earbuds contain electrodes that pick up electrical signals by making contact with the ear canal. Reporting in Nature Communications, researchers showed that this tool can detect so-called alpha waves, which are electrical signals in the brain that are known to increase when a person closes their eyes or begins to drift off to sleep.
"We believe that this technology has many potential uses, and that classifying drowsiness is a good indicator that the technology can be used to classify sleep and even diagnose sleep disorders," said senior study author Rikky Muller, an associate professor at the University of California, Berkeley.
Earbuds couldn't be instantly converted to mini-EEG machines. The researchers started by creating a device that could comfortably fit into ear canals of different shapes and sizes, and make the right contact with skin. The team also wanted to make something that could be used without gels, like similar devices under development by other research teams.
"My personal goal was to try to make a device that could be used every day by someone who would really benefit from it," said co-first study author Ryan Kaveh, a UC Berkeley postdoctoral scholar. Not only should many people be able to use and reuse it, Kaveh wanted it to be easy to manufacture.
The final design is available in three sizes, and incorporates flexible electrodes. A low-power, wireless interface delivers the data.
The team also demonstrated the device with nine volunteers, who wore the earbuds while completing some boring tasks in a dark room. The volunteers were asked to rate their drowsiness level at various points.
"We found that even when the signal quality from the earpieces seemed worse, we could still classify the onset of drowsiness with the same level of accuracy as much more complicated, bulky systems," Kaveh said.
The team is continuing to refine and improve the device, as well as look for other applications. This tech might one day be used by clinicians who want to monitor hearts, or jaw clenching, for example.
Sources: University of California - Berkeley, Nature Communications