“The show must go on,” so they say. These days, whether you’re an opera singer, a teacher, or just someone with a lot of video meetings, you rely on your voice to work. But what if your voice is under threat? Work it too hard, or for too long, and you might find that it suddenly lets you down.

Researchers from Northwestern University have developed a new technology to protect against this happenstance. It’s the first wearable device that monitors vocal usage and calls for time out before damage occurs. The research has been published in the Proceedings of the National Academy of Sciences.

You Better Work

Vocal fatigue is a common problem, and highly familiar for people who earn their living using their voices. Those who make their money as orators, singers, or performers are exceedingly familiar with this risk. Those outside these fields may be less attuned to the problem, but it can nevertheless hit any of us if we overuse our voices. The problem is when overworked vocal folds swell up, causing the voice to become raspy and lose its endurance. Singers are especially at risk, as vocal fatigue can put their abilities to hold a tune in jeopardy. It can, in worst case scenarios, be the lethal blow that ends a career.

The root cause of this problem is an underappreciation of the physical demands of vocal activities. People often fail to make the connection between their daily vocal activities and the impact on their vocal health until hoarseness sets in. If you’ve ever been to a wedding and chatted the night away in a loud room, or you’ve sung a demanding punk set at karaoke, you might have noticed the next day your voice was all skunked up. That’s vocal fatigue at play.

Early Warning

The new wearable technology developed by researchers aims to prevent vocal fatigue before it happens. The wearable, no larger than a postage stamp, is soft, flexible, and comfortably attaches to the upper chest. Here, it monitors the vibrations associated with talking and singing. The data is then streamed in real-time via Bluetooth to a smartphone or tablet, allowing the users to monitor their voices in action.

The postage stamp-sized device attaches to the sternum, just below the neck, via a sticky pad. The device is able to tease out the difference between regular speech and singing, and assess vocal use over time. This is achieved with machine-learning algorithms, enabling users to separately track their vocal loads. Users can set personal vocal thresholds within the device’s accompanying app, and receive real-time haptic feedback when they approach their limit, prompting them to rest their voices before overuse. The wearable device is paired with a haptic feedback gadget akin to a wristwatch, providing a subtle cue on when it’s time to rest.

While other vocal-monitoring devices exist, they are often somewhat impractical for regular wear. They typically rely on  bulky, wired designs and have intrusive audio recording capabilities. These can also fall down in noisy environments like choirs or crowded rooms, where the device can easily be confused by audio from other speakers or singers. This new wearable device, however, senses vibrations directly through contact to measure vocal activity instead of recording actual audio. This not only allows for a more accurate tracking of personal vocal usage, but also sidesteps privacy concerns associated with audio capture.

The research builds on previous work which developed devices to track the recovery processes of stroke patients and to monitor coughing in the early weeks of the COVID-19 pandemic. Like those prior diagnostic devices, the vocal monitoring wearable device can capture body temperature, heart rates, and respiratory activity for extra background on vocal condition. The research team sees these extra data points as an opportunity to explore fundamental questions concerning vocal fatigue. For instance, future research could examine whether physical exertion while singing impose additional stress on the vocal cords.

For now, the device remains a piece of research hardware for investigating vocal fatigue issues. However, given the hardware and software has been developed, it’s not hard to see this as a potentially useful product for the vocal-conscious. While vocal fatigue is a niche problem that most of us simply deal with on an occasional basis, for professional orators and singers, such a tool could be of great use.