New tool can measure lung functions over phone call

Scientists, including those of Indian-origin, have developed a new health sensing tool that can accurately measure lung function over a simple call made using any phone - not just a smartphone.
Most people in the developing world who have asthma, cystic fibrosis or other chronic lung diseases have no way to measure how well their lungs are functioning outside of a clinic or doctor visit.
"We wanted to be able to measure lung function on any type of phone you might encounter around the world - smartphones, landlines, pay phones," said Shwetak Patel, at the University of Washington (UW).
"With SpiroCall, you can call a 1-800 number, blow into the phone and use the telephone network to test your lung function," Patel said.

Earlier the researchers had developed SpiroSmart, an app that lets people monitor their lung function by blowing into their smartphones.
The patients take a deep breath in and exhale as hard and fast as they can until they can't exhale any more.

The phone's microphone senses sound and pressure from that exhalation and sends the data to a central server, which uses machine learning algorithms to convert the data into standard measurements of lung function.
Researchers collected data from more than 4,000 patients who have visited clinics in US as well as in India and Bangladesh, where clinicians have measured lung function using both SpiroSmart and a commercial spirometer.

That comparative data has improved the performance of the machine learning algorithms, researchers said.
In surveying patients from India and Bangladesh, the team realised that a significant percentage did not own smartphones.
Since the only sensor they were using was a microphone, which all phones have, the researchers, including UW doctoral student Mayank Goel, decided to develop a system that would work with any phone anywhere in the world by having the patient use a call-in service.
SpiroCall transmits the collected audio using a standard phone channel - as opposed to a sound file that is transferred by a smartphone app over the Internet.

The team combined multiple regression algorithms to provide reliable lung function estimates despite the degraded audio quality.
The research team also developed a 3D printed whistle that can be used in conjunction with SpiroCall that changes pitch when the patient exhales.
The whistle is designed to address training challenges by enabling patients to hear what a "good" test sounds like.
The whistle also improved the test performance for patients who are very ill, whose vocal cords are not able produce enough sound for the phone's microphone to pick up.