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Today, when doctors suspect that a patient has a cardiac arrhythmia that could lead to a heart attack, they can implant a tiny cardiac monitor smaller than a AAA battery in the patient's chest, directly over the heart. The company that makes that monitor, Medtronic, thinks the day will come when perfectly healthy people will be clamoring to have that gear inside them as well.

At a Medical Design & Manufacturing conference today, Medtronic program director Mark Phelps described his company's successful efforts to miniaturize its cardiac technologies. In February, the company began a clinical trial of its pill-sized pacemaker, which is implanted inside the heart. While Phelps presented that tiny pacemaker as a remarkable feat of engineering, he saved his real excitement for the tiny Linq cardiac monitor, which went on sale this year. Phelps declared that the device heralded "the beginning of a new industry" in diagnostic and monitoring implants.

Phelps argued that such an implant could be enhanced with more sensors to give people reams of biometric information, which would improve their healthcare throughout their lives. Young healthy people could use the sensors to track heart rate and calories burned, the kind of information that quantified selfers get today from wearable gadgets like the Fitbit. Later, the sensors would help with disease management, as they could be programmed to monitor particular organs or systems. Finally, they could enable independent living for the elderly by allowing doctors to keep watch over their patients remotely. "I would argue that it will eventually be seen as negligent not to have these sensors," Phelps said. "It's like driving without any gauges of your feedback systems."

The data generated by these implants would be provided to both the patient and the physician, Phelps said, and would allow both to see how lifestyle changes affect the patient's health over time, or how his or her body reacts to certain pharmaceuticals. This Big Data approach could enable a shift from reactive, symptom-based medicine to a preventative care model.

Such a medical system would be intrusive in two senses, Phelps admitted: Not only would doctors be physically cutting into a patient's body, they would also be exposing a great deal of the patient's biometric data. Yet Phelps believes that people will embrace the sensor-enabled lifestyle. "You'll get so used to having that feedback and information, you won't be able to imagine life without it," he said.

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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
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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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64 channels

Since optogenetic therapies are just beginning to be tested in clinical trials, there’s still some uncertainty about how best to make the technique work in humans. We’re still thinking about how to get the viral vector to deliver the necessary genes to the correct neurons in the cochlea. The viral vector we’ve used in experiments thus far, an adeno-associated virus, is a harmless virus that has already been approved for use in several gene therapies, and we’re using some genetic tricks and local administration to target cochlear neurons specifically. We’ve already begun gathering data about the stability of the optogenetically altered cells and whether they’ll need repeated injections of the channelrhodopsin genes to stay responsive to light.

Our roadmap to clinical trials is very ambitious. We’re working now to finalize and freeze the design of the device, and we have ongoing preclinical studies in animals to check for phototoxicity and prove the efficacy of the basic idea. We aim to begin our first-in-human study in 2026, in which we’ll find the safest dose for the gene therapy. We hope to launch a large phase 3 clinical trial in 2028 to collect data that we’ll use in submitting the device for regulatory approval, which we could win in the early 2030s.

We foresee a future in which beams of light can bring rich soundscapes to people with profound hearing loss or deafness. We hope that the optical cochlear implant will enable them to pick out voices in a busy meeting, appreciate the subtleties of their favorite songs, and take in the full spectrum of sound—from trilling birdsongs to booming bass notes. We think this technology has the potential to illuminate their auditory worlds.

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