This article is part of our exclusive IEEE Journal Watch series in partnership with IEEE Xplore.

Although a pregnancy is an exciting time for expecting parents, it can involve many trips to a doctor’s office to monitor the health of the fetus. Currently, the most common method for monitoring the heartbeat of a fetus is through an ultrasound test—which requires not only a visit to a doctor’s office but also the expertise of a trained technician.

In the search for a simpler approach, researchers have developed a novel system that includes a wearable device, a smartphone, and an algorithm that could offer at-home monitoring of a fetus’s cardiac health. The new algorithm, dubbed Lullaby, is described in a study published on 19 August in IEEE Sensors Letters.

The wearable device involves a patch that’s placed on the abdomen of a pregnant user in addition to electrodes that monitor the electrocardiogram (ECG) signals from the fetus. The device also includes a microcontroller that processes the signals and sends them via Bluetooth to a smartphone or watch. Users can then view the data on an app.

However, a major challenge with this type of tech is that continuous ECG monitoring involves a lot of data to process, which has made real-time monitoring with wearable devices challenging. The new Lullaby algorithm addresses this issue.

“Lullaby was made to push the boundaries of the field by creating an algorithm that could process high-resolution ECG in real time and on a wearable device,” explains Daniel Jilani, an undergraduate researcher at University of California, Irvine, who co-led the development of this technology.

The system works by exploiting the fact that a heartbeat has a steady rhythm. The device uses this temporal pattern to better distinguish between true and false heartbeats, thereby focusing its computational power more on the heartbeats themselves, rather than the cardiac activity between heartbeats. This approach reduces the amount of computation required to process the data and extract the fetal heartbeats.

This fetal cardiac-monitoring system uses a patch with electrodes, which record the abdominal ECG signals of a pregnant user. The novel system is currently being developed jointly by Sensoriis and HERO Laboratory.Tai Le

In their study, the researchers used a data set of abdominal ECG recordings to test the Lullaby approach against other existing ECG-processing algorithms, finding it to be nearly seven to 1,000 times as fast as these existing options.

“In terms of power, we believe that the algorithm is efficient enough to run continuously [on a smartphone] for days or weeks,” says Jilani. “In terms of RAM memory, the Lullaby algorithm uses memory on the scale of kilobytes, meaning it can run on memory-limited devices such as microcontrollers and smartwatches.”

The researchers do not yet know how accurate the Lullaby approach is compared to a traditional ultrasound test, but they note that ultrasound devices are less accessible, more expensive, and more difficult to operate than an ECG. What’s more, ultrasound tests are done during a visit to the doctor’s office, whereas a wearable ECG device can provide more continuous monitoring as a pregnant user goes about their normal day. Significantly, this technology could be especially impactful by making fetal heart monitoring more accessible to low-income and disadvantaged communities, Jilani notes.

Since this initial study, Jilani says the team has already greatly improved the algorithm to be more accurate and faster than the original version, and they are working toward implementing it in a full system. This includes work on a mobile app that can be used on smart phones to support fetal heart monitoring.

They have a provisional joint patent on the Lullaby algorithm with the University of California, Irvine, and have teamed up with a sponsoring company, Sensoriis, to produce a novel fetal cardiac-monitoring system that uses it.

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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
Blue

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.


8 channels


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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