Engineers have developed a system, dubbed the SpiroCall, which measures the lung function of people with conditions such as asthma or cystic fibrosis by blowing into any type of phone.
Any type of phone means a simple landline, an old mobile phone or a more sophisticated smartphone. The test works in all cases as it doesn’t rely on any intelligent app.
Instead, it transmits data from the phone’s microphone into a server on the other side of the line.
SpiroCall was developed by engineers from University of Washington (UW) and is designed to help people in remote areas, for whom regular visits to a doctor are too difficult.
"We wanted to be able to measure lung function on any type of phone you might encounter around the world -- smartphones, dumb phones, landlines, pay phones," said Shwetak Patel, Professor of Computer Science and Engineering and Electrical Engineering at the UW. "With SpiroCall, you can call a 1-800 number, blow into the phone and use the telephone network to test your lung function."
The team behind the project previously developed an app for smartphones for exactly the same thing. However they found that, especially in developing countries, not everyone has a smartphone. The SpiroCall system uses the same algorithms, but is run on a computer instead of on the phone. The patient takes a deep breath and exhales with full force into the microphone, which detects the sound and pressure. The data is then forwarded via the standard phone channel.
"People have to manage chronic lung diseases for their entire lives," said lead author Mayank Goel, a UW computer science and engineering doctoral student. "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."
Although audio data collected via the telephone are of poorer quality, when compared to data from commercial spirometers, results from the SpiroCall were within 6.2 per cent identical. As there is variability in the way a patient exhales during each spirometry test, the industry considers anywhere from 5 to 10 per cent to be within an acceptable margin of error.