Researchers at the University of Washington have developed a low-cost hearing test for newborns. Traditionally, the equipment for such testing is quite expensive. As newborns cannot let us know if they can hear something, the test is based on creating a noise within the ear canal and then listening to the vibrations created by the specialized hair cells within.
The UW researchers used cheap earbuds that are connected to a small microphone that can listen to the vibrations of the hair cells. A smartphone app then analyzes the sounds and can provide guidance to attend a specialist if abnormal results arise.
Performing a hearing test with newborns is important to make sure that they receive the support they require if it turns out that they have a hearing issue. However, in many places in the world, people do not have access to the testing equipment required for these procedures.
“There is a huge amount of health inequity in the world. I grew up in a country where there was no hearing screening available, in part because the screening device itself is pretty expensive,” said Shyam Gollakota, one of the developers of the technology. “The project here is to leverage the ubiquity of mobile devices people across the world already have — smartphones and $2 to $3 earbuds — to make newborn hearing screening something that’s accessible to all without sacrificing quality.”
The traditional way to test newborn hearing is to create sounds in the ear at two different tones. This causes the hair cells in the ear to vibrate, creating a third tone. The equipment listens for this third tone to interpret the test results. However, the traditional equipment used to perform this procedure is very expensive, in part because its speakers must be able to play the two different tones without any interference.
These researchers turned to inexpensive earbuds as an alternative, and allow each earbud to play a different tone. The earbuds are also attached to a small microphone that can listen for the returning tone from the hair cells and a smartphone app uses algorithms to analyze the results, and reduce the effects of background noise and interference.
“As you can imagine, these sounds that are coming out from the ear are very soft, and sometimes it’s hard to hear them over noise in the environment or if the patient is moving their head,” said Justin Chan, another researcher involved in the project. “We designed algorithms on the phone that help us detect the signal even with all that background noise. These algorithms can run in real time on any smartphone and do not require the latest smartphone models.”
Study in journal Nature Biomedical Engineering: An off-the-shelf otoacoustic-emission probe for hearing screening via a smartphone