Say ‘ahhh’ to the smartphone: It’s a new tool for detecting COVID-19

Sonde Health's app searches for subtle changes in the timbre of a voice

Sonde One is a new app that analyzes a person's voice to detect potential COVID-19 symptoms.Sonde Health

A Boston company says it has developed a new way to spot symptoms of COVID-19: Just pick up your smartphone and say “ahhh.”

Sonde Health is one of several companies pioneering a new kind of diagnostic technology that uses “vocal biomarkers.” These are subtle changes in a person’s voice that can be identified by a computer. These changes could indicate the presence of illness — not just COVID, but also other lung and heart ailments, and even anxiety and depression.

It might sound a little too hocus-pocus, but to Amir Lerman, a cardiologist and professor of medicine at the Mayo Clinic in Rochester, Minn., who is not affiliated with Sonde Health, it makes perfect sense. The voice, Lerman said, “is like any other signal that’s coming from the body. It’s something that you can actually, with the right technology, make as a marker for disease.”

For example, Lerman’s own research has found that changes in the voices of patients can predict impending heart failure.

But these days, COVID detection is the hottest market in diagnostics, and Sonde Health is diving in. The company has just launched Sonde One, a service that uses a smartphone app to test a user’s voice for signs of infection. The app is for sale to companies that want to run daily health checks on employees before allowing them to report for work.

David Liu, Sonde Health’s chief executive, stressed that Sonde One can’t diagnose the disease on its own. “We are not telling you whether or not you have COVID,” Liu said. Instead, the software just detects changes in the voice that are consistent with the disease, usually subtle changes that the human ear wouldn’t pick up.

App users first train the software by saying “ahhh” five to 10 times into the microphone. This provides a baseline measurement of the person’s voice. From then on, the person simply says “ahhh” for six seconds when prompted by the app. The software searches the digitized voice data for any changes.

For instance, respiratory problems caused by COVID and other illnesses will often lead to changes in timbre, the complex mix of frequencies that gives a unique sound to every person’s voice. Timbre is why a trumpet sounds different from a saxophone playing the same note. And subtle changes in timbre can reveal the presence of an infection.

But the voice test is only the beginning. Users would have to complete a questionnaire that checks for symptoms or any recent contacts with infected people. The Sonde One software combines this information with the voice test to decide whether the worker should call the doctor for an actual COVID-19 test.

Sonde isn’t alone in trying to track COVID-19 infections through vocal cues. VocalisHealth, an Israeli company with a Boston-based management team, is testing a similar product.

“Like a lot of people, our world changed in February,” said Michael Seggev, VocalisHealth’s chief commercial officer. The company originally focused on diseases ranging from sleep apnea to congestive heart failure. But today it’s all-in on vocal tests for the coronavirus.

“We have developed a vocal biomarker that’s specific to COVID-19,” said Seggev, whose company launched a clinical trial of the technology in Israel in March.

Sonde Health was founded in 2015, based on technologies developed at the Massachusetts Institute of Technology’s Lincoln Laboratory. The original plan was to measure a person’s voice to detect neurological disorders like Parkinson’s disease and concussion.

About six months ago, Sonde Health researchers began to study illnesses that affect the lungs, like asthma and chronic obstructive pulmonary disease. The company collected 300,000 voice samples from 50,000 people in the United States and India. The samples came from people who spoke seven different languages, but Liu said it didn’t matter; they were analyzing their tones of voice, not their words. Sonde Health ran the digitized samples through an artificial intelligence system that learned to recognize the variations in sound that indicate lung problems.

“There are a hundred different muscles and parts of the body that need to come together for you to be able to speak,” Liu said. If a disease affects any of these body parts, “it’s going to change the physiology of speech, and the sound that you make from your voice.”

The shift toward studying respiratory illness was perfectly timed; Sonde Health had already completed much of the research needed to bring a product to market.

But Liu said that Sonde Health will continue to develop vocal biomarker tests for a broad range of ailments. An unnamed health care provider in India is already using its software to test patients for symptoms of depression.