In-Ear EEG Makes Unobtrusive Brain-Hacking Gadgets a Real Possibility

Man wearing an earplug-like device that's connected by a wire to a headset
Photo: Max Curran

Brain hacking gadgets could soon be an unobtrusive part of daily life, thanks to EEG sensors that fit snugly inside the ear. Two research groups are making progress on discreet devices that offer reliable brain data—and that reliability is a key point. A few neuro gadgets for consumers have already hit the market, but it’s not at all clear that they deliver the promised brain data. 

Why might you want a brain hacking gadget? Well, maybe you want to control objects in the physical world with your mind, and long to use a mere thought to unlock your front door or raise your X-wing spaceship from a swamp. Or perhaps you want to keep tabs on your brainwaves throughout the day, and seek a data-collecting gadget that acts as a Fitbit for your brain. 

Companies and DIYers can make such things today (okay, probably not the X-wing lifter) with sensors that use electroencephalography, or EEG, to pick up a rough recording of brain activity. Typically, these devices use EEG electrodes that are affixed to the scalp, where they detect the patterns of electrical activity generated when millions of brain cells act in concert. The different types of “brainwaves” have been associated with different mental states, such as focus and relaxation, and different actions.

But such scalp-based electrode systems can look a little conspicuous and clunky. While startups are certainly racing to make sleeker and better EEG headsets, several research groups think that in-ear EEG sensors offer an elegant alternative.

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Photo: Max Curran
Researchers tweaked a commercial EEG-reading device by routing the electrode to the ear.

At John Chuang’s lab at UC Berkeley, engineers modified a commercial EEG headset from the Silicon Valley company NeuroSky, taking the electrode out of the plastic forehead piece and bringing it to the ear canal. The team decided to work with “the cheapest available consumer-grade EEG headset,” Chuang says in an email, to see what they could achieve with that “challenging” setup. 

The team’s ultimate goal is to use an in-ear EEG sensor to send mental commands that could control a computer, a drone, or any other electronic thing. But EEG isn’t a very clear signal. It can distinguish broad patterns such as alpha waves (with frequencies between 8 and 13 Hertz) generated when a user is resting with eyes closed, and beta waves (13 to 30 Hz), which are generated when the user is more alert. But it can’t decipher verbalized thoughts like “Go left, car!” 

To use EEG in a brain-machine interface, then, researchers calibrate their systems by having the user perform “mental gestures” and identifying the EEG signatures of those efforts. Chuang’s team tried out a five different mental gestures: Test subjects sang a song inside their head, imagined a face, pictured a rotating cube, listened to a sound, and simply breathed deeply with their eyes closed.

For each person, the researchers chose the two gestures with the clearest EEG signatures. These two mental gestures could theoretically be used to create a binary control system for any hooked-up electronic device. For example, a user could imagine the rotating cube in order to make a remote-controlled car move forward, and picture a face to make it stop. Of course, steering the car left or right would require a more sophisticated system. Chuang’s team presented their research at the IEEE Body Sensor Network conference last month. 

Chuang says this research points toward brainwave-sensing earbuds that quietly convey our commands to the machines in our lives. “Personally, I feel awkward speaking to my devices, or making gestures by waving my hands in the air,” he tells Spectrum. In-ear EEG could provide “a very natural and discreet way for us to ‘talk’ to our computers,” he says. 

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Photo: Danilo Mandic
This in-ear EEG sensor uses an off-the-shelf noise-blocking earplug.

Meanwhile, Danilo Mandic’s lab at Imperial College London has been through several iterations of an earbud-like EEG device. Their latest version uses a simple noise-blocking earplug made of a spongy material called memory foam. Such earplugs conform naturally to the shape of a user’s ear, enabling excellent contact with the skin inside the ear canal. By attaching two electrodes made of a soft silver-coated fabric to the sides of an earplug, the researchers obtained high-quality EEG signals. 

By inventing a device that’s cheap, unobtrusive, and comfortable, Mandic says his group is clearing the way for a “truly wearable” EEG system. “The ear-EEG also opens up completely new avenues in 24/7 monitoring of the state of body and mind,” Mandic says in an email. He imagines possibilities such as using EEG to monitor the progress of chronic diseases, to track sleep patterns, or to keep tabs on military personnel’s mental state and fitness for duty.

Outside of the lab, a Kickstarter campaign for an in-ear gadget with a built-in EEG sensor raised more than $150,000 this spring. That gadget, called Aware, requires a 3-D scan of the user’s ear canal to produce a customized ear piece. It will be interesting to see who else jumps into this brand new commercial sector (iBrain, anyone?).

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The Human OS

IEEE Spectrum’s biomedical engineering blog, featuring the wearable sensors, big data analytics, and implanted devices that enable new ventures in personalized medicine.

 
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