She has the power to charm audiences, woo lovers and irritate neighbors, and she's damn delicate. What is she? You guessed it, our voice. Each person's distinctive sound produced when air from the lungs causes the vocal cords, folds of muscle tissue in the larynx, to vibrate. Well, these vocal cords can easily become damaged from stress, infection, or overuse. It's not just artists who risk ending up without a voice: according to a well-known twenty-year study, 30% of the population will experience a voice disorder at some point in their lives. But now a group of bioengineering researchers at UCLA may have found a promising solution.
A patch that reads muscles and makes you speak without a voice
The study was published this week in the journal Nature Communications (I link it here). The UCLA team presented and tested a soft patch that can be applied to a person's neck: from there it will detect muscle movements and, with the help of machine learning algorithms that process the signals, translate them into audible words.
While the device is still an early prototype, it has the potential to offer a substantial improvement over current alternatives. When a person is left without a voice today, the easiest solution is to resort to typing, texting, or written notes to communicate. But as he points out Jun Chen, the study's lead author, typing can be slow and awkward. Writing legible notes, however, is only possible with good lighting. More sophisticated solutions such as electrolarynxes, external devices held against the throat to produce the vibrations needed for speech, may require special training to use, and surgeries are often daunting due to their invasiveness. A patch, in theory, would be able to overcome all these obstacles.
Magnetic nanoparticles: the secret of the talking patch
The mechanism behind the UCLA device? It is a principle known as the magnetoelastic effect. When magnetic nanoparticles are embedded in soft materials such as elastic or silicone polymers, their magnetic properties can change when the material is stretched. This is because each deformation causes the particles to rotate or move relative to each other, changing the magnetization of the material.
When the throat muscles move under the silicone patch, the resulting changes in the magnetic field can also be converted into electrical signals. In a test with eight participants, the researchers captured signals that arose as the subjects spoke and lip-sync five different phrases (including: “I hope your experiments are going well!”, “Merry Christmas!” and "I love you!"). They then trained a machine learning model to recognize the distinct shapes of the electrical signals associated with each sentence. This algorithm was then able to predict which of the five sentences the participants had uttered – both aloud and without a voice – with an accuracy greater than 90%.
A hope for millions of voiceless people
Of course, there is still a way to go: for now the device can only recognize the five sentences on which it was trained. Furthermore, individual differences in vocal folds mean that the algorithm currently needs to be customized for each user. To make it practical on a large scale, researchers will need to collect a lot more data, but given how quickly these technologies are growing, the prospects are exciting. Imagine what this patch could mean for the millions of people who lose their voices every year due to illness, accidents or surgery. Or for those who, for whatever reason, find it difficult or impossible to speak.
With this device, they could regain the ability to communicate in a natural and spontaneous way, without having to resort to slow and cumbersome methods. They could participate in conversations again, express emotions, tell stories. Because the voice is not just a means of communication. It is an integral part of our identity, our personality, our being. Losing your voice doesn't just mean losing the ability to produce sounds, but also a part of yourself. For this reason, such a patch is not just a technological gadget, but a promise of hope. The hope of giving back to those who have lost not just a voice, but a piece of soul.
