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AI-Enabled Device Emits Radio Waves to Wirelessly Monitor Sleep Patterns at Home

A laptop-sized system could make it easier to diagnose and study sleep disorders

2 min read
A photo illustration shows a laptop-sized device that monitors sleep patterns mounted to a window in a home office
Photo Illustration: Shichao Yue/MIT

Around 50 million people in the U.S. suffer from sleep disorders. In order for physicians to diagnose these disorders, patients must spend a night in a sleep lab hooked up to electrodes and sensors, which can be unpleasant and nerve-racking.

MIT researchers have now come up with a way to wirelessly capture data on sleep patterns from the comfort of a patient’s home. Their laptop-sized device bounces radio waves off a person, and a smart algorithm analyzes the signals to accurately decode the patient's sleep patterns.

The device could allow experts to monitor someone’s sleep for weeks or months rather than once every few months in an overnight lab. Apart from enabling physicians to diagnose and study sleep disorders, they could also use it to understand how drugs or illnesses such as Parkinson’s disease, Alzheimer’s disease, epilepsy, and depression affect sleep quality.

“Doing this wirelessly in your own bedroom, you could really see the impact of drugs, and progression of diseases by long-term monitoring,” says Dina Katabi, a professor of electrical engineering and computer science at MIT who led the work.

During sleep, we cycle through three different sleep stages: light, deep, and REM. Fitness bands and phone apps use accelerometers to track a person’s sleep patterns, but they don’t produce data on sleep stages that is accurate enough for medical use, Katabi says.

The new RF system combines information on breathing, pulse, and movements to decipher sleep stages with 80 percent accuracy, about the same as lab-based EEG tests. The researchers tested the system on 25 volunteers over 100 nights of sleep. They presented their work at the International Conference on Machine Learning on Aug 9.

The device transmits RF waves at one-thousandth the power of Wi-Fi signals and picks up signals reflected from walls, furniture, and sleeping subjects, whose tiniest movements change the frequency of the reflected signal. The deep neural network algorithm extracts the relevant sleep-related signals from the jumble of reflected signals and translates the data into meaningful sleep stages.

The MIT team has previously used the same radio-based system to measure walking speed and to detect and analyze emotions.

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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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