For Dieters, Smart Glasses Could Detect and Record Every Chew

Eyeglasses with EMG sensors can tell whether you're munching on cookies or Jelly Babies

2 min read
Man wearing white plastic glasses made via 3-D printing
These sensor-equipped glasses can inconspicuously monitor the wearer's food chewing.
Photo: University of Passau

Whether you’re trying to lose weight, eat healthier, or track your diet for other reasons, there’s no truly easy and automatic way to log your food intake. Today’s best options are apps that require you to pick the food items you’re consuming or manually enter that information.  

But what if the app knew, without your help, that you’d just spent a half hour crunching on cookies? 

That’s the idea behind the “Diet Eyeglasses” revealed earlier this month at the IEEE Body Sensor Networks conference in San Francisco. The smart glasses have built-in sensors that detect muscle activity related to chewing, which could enable the continuous and unobtrusive monitoring of every morsel users chow down on.

Professor Oliver Amft, a researcher at Germany’s University of Passau, 3-D printed his smart glasses. They look like normal spectacles, but feature sensors made from flexible woven fabric electrodes attached to the glasses’ frame. The sensors use electromyography (EMG) to detect contractions of facial muscles involved in chewing. After experimenting with different locations for the sensors, Amft and his students found that tucking them into the frame behind the ears produces the best contact with the user’s skin, and thus the best signal. The small processor and rechargeable battery are also attached behind the ear. 

To test out the specs, eight research subjects chewed various foods, swallowed water, coughed, spoke, and made random motions with their heads. The smart glasses were able to clearly differentiate the EMG patterns produced by chewing from those produced by other activities. They could also tell the difference between the different foods included in the test: cookies, bananas, toast, carrots, and a beloved European candy called Jelly Babies. The foods’ textures were distinct enough to produce signature EMG patterns, the researchers showed. 

However, the researchers say it’s doubtful that the glasses alone can distinguish between a wide variety of food types. You can see the difficulty of relying solely on texture information: Could such a system tell the difference between eggs and oatmeal? But the glasses could be used in combination with other sensors, the researchers suggest, to create “personalized dietary monitoring systems.” 

There are a number of options for sensors that use other modalities to track food consumption. One gadget covered recently in this blog listens in on the user’s meal; its microphones attach to the user’s neck and detect the sounds of biting, chewing, and swallowing to classify food items. In another approach, a team of experts in natural language processing and machine learning devised a system that could parse a user’s natural description of a meal and retrieve the relevant nutritional information.  

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Restoring Hearing With Beams of Light

Gene therapy and optoelectronics could radically upgrade hearing for millions of people

13 min read
A computer graphic shows a gray structure that’s curled like a snail’s shell. A big purple line runs through it. Many clusters of smaller red lines are scattered throughout the curled structure.

Human hearing depends on the cochlea, a snail-shaped structure in the inner ear. A new kind of cochlear implant for people with disabling hearing loss would use beams of light to stimulate the cochlear nerve.

Lakshay Khurana and Daniel Keppeler

There’s a popular misconception that cochlear implants restore natural hearing. In fact, these marvels of engineering give people a new kind of “electric hearing” that they must learn how to use.

Natural hearing results from vibrations hitting tiny structures called hair cells within the cochlea in the inner ear. A cochlear implant bypasses the damaged or dysfunctional parts of the ear and uses electrodes to directly stimulate the cochlear nerve, which sends signals to the brain. When my hearing-impaired patients have their cochlear implants turned on for the first time, they often report that voices sound flat and robotic and that background noises blur together and drown out voices. Although users can have many sessions with technicians to “tune” and adjust their implants’ settings to make sounds more pleasant and helpful, there’s a limit to what can be achieved with today’s technology.

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