We're truly in the golden age of technology. Download the right apps, and your phone can summon pizza, a taxi, or even a date. But engineers have designed a program that may prove to be even more impressive: one that tests patients’ lung function over the phone—even landlines. New market testing results on the program, called SpiroCall, will be presented [PDF] at the Association for Computing Machinery's conference this month. 

Lung conditions like asthma and chronic obstructive pulmonary disease affect hundreds of millions of people around the world. These conditions are exacerbated by air pollution, allergens, and industrial chemicals, which means that people in low- and middle-income countries are hit especially hard. At the same time, people with chronic illnesses need more medical care than most, but that care can be hard to come by in remote or impoverished areas.

"People have to manage chronic lung diseases for their entire lives," said presenter and University of Washington (UW) engineer Mayank Goel in a press statement. "So there's a real need to have a device that allows patients to accurately monitor their condition at home without having to constantly visit a medical clinic, which in some places requires hours or days of travel."

So Goel and his colleagues developed a smartphone app called SpiroSmart (the “Spiro” part comes from “spirometer,” which is the tool doctors use in the office to measure lung function). To use the app, a person takes a deep breath, then blows as hard and fast as they can into their smartphone’s microphone until they run out of breath. The microphone then quantifies the pressure and sound from the user’s exhalation and reports that data to an algorithm, which turns those numbers into measurements of lung function.

The scientists brought the app into clinics in Seattle and Tacoma, Washington, as well as in India and Bangladesh. They tested the algorithm on more than 4000 patients, whose measurements were also taken using a traditional clinical spirometer.

A patient tests the SpiroSmart app by breathing into a smartphone held by engineer and app developer Mayank Goel. Image credit: University of Washington

The app fared surprisingly well. But as they talked to patients in Bangladesh and India, the engineers learned that many of their intended users don't own smartphones, which means they’d still need to go to a clinic for testing, making the app redundant. They realized that, to be truly useful, their program would have to be accessible from any phone, be they home phones or public pay phones.

Their solution? A hotline. SpiroCall, the newest version of the lung testing program, can be accessed not through an app but by dialing a 1-800 number. Instead of relying on a smartphone to transmit the data, the user’s breath data is collected by a recorder on the hotline itself. This took some tinkering, since the sound quality of landline calls can be pretty poor. But even with these challenges, SpiroCall did quite well, consistently producing results that were within 6.2 percent of those from the spirometer.

The hotline is not ready for primetime just yet. The researchers are still collecting data and trying to determine the best way to share results with patients.

"Our research area is not just about sensing, but human-centered sensing," Goel said. "Because this project has been around for four years, we've been able to talk to a lot of patients about how they're able to use the technology, and that feedback has really helped us make smart improvements."