Doctors and researchers at the University of Washington have developed a smart phone app that can detect ear infections in children. Using only the app and a folded piece of paper, it can detect an ear infection with 85% accuracy. The app does this by producing a series of soft chirps that are directed into the ear via a paper funnel. The team's work was recently published in Science Translational Medicine.
“Designing an accurate screening tool on something as ubiquitous as a smartphone can be game changing for parents as well as health care providers in resource limited regions,” says Shyam Gollakota, associate professor at the University of Washington Paul G. Allen School of Computer Science & Engineering and co-author of the study. “A key advantage of our technology is that it does not require any additional hardware other than a piece of paper and a software app running on the smartphone.”
From the University of Washington article: "This app works by sending sounds into the ear and measuring how those sound waves change as they bounce off the eardrum. The team’s system involves a smartphone and a regular piece of paper that the doctor or parent can cut and fold into a funnel. The funnel rests on the outer ear and guides sound waves in and out of the ear canal. When the phone plays a continuous 150 millisecond sound — which sounds like a bird chirping — through the funnel, the sound waves bounce off the eardrum, travel back through the funnel and are picked up by the smartphone’s microphone along with the original chirps. Depending on whether there’s fluid inside, the reflected sound waves interfere with the original chirp sound waves differently.
When there is no fluid behind the eardrum, the eardrum vibrates and sends a variety of sound waves back. These sound waves mildly interfere with the original chirp, creating a broad, shallow dip in the overall signal. But when the eardrum has fluid behind it, it doesn’t vibrate as well and reflects the original sound waves back. They interfere more strongly with the original chirp and create a narrow, deep dip in the signal."
Read more about the smartphone app that can "hear" ear infections at University of Washington.