Researchers have created a way for a smartphone to “hear” a warning sign of ear infections — fluid buildup behind the eardrum.
If it pans out, parents might one day check their tots’ ears at home simply using a phone app and “stuff you have around the house — paper, tape and scissors,” said one of the lead researchers, Dr. Sharat Raju of the University of Washington.
Ear infections are one of the most common reasons for pediatrician visits. Even if there’s no infection, fluid that builds up in the middle ear still can be painful and sometimes can muffle hearing enough to affect speech development.
Diagnosis is difficult. Usually a pediatrician will peek into the child’s ear to see if the eardrum is inflamed, and parents can buy devices that use cameras to do the same thing. But ear specialists tend to use pricier, more complex tests that measure if the eardrum is pliable enough to vibrate correctly in response to sound, or is stiff from the pressure of fluid behind it.
A team of engineers and doctors at the University of Washington developed a simple smartphone approach for acoustic testing: Cut a piece of paper, fold it into a funnel shape and tape it around the phone’s microphone and speakers. Aim the funnel at the ear canal to focus sound. An experimental app beams in birdlike chirps, at a specific frequency. The microphone detects sound waves bouncing off the eardrum.
The app analyzes that echo, a broad-spectrum vibration from a healthy eardrum. Pus or uninfected fluid alters the eardrum’s mobility and changes the reflected sound. The app sends a text saying whether it’s likely that middle-ear fluid is present — one piece of information, along with other symptoms, that might be used for diagnosis.
“This type of technology could potentially avoid needless doctor visits,” said Dr. Justin Golub, a Columbia University ear specialist who wasn’t involved with the research. Golub often sees patients with suspected ear infections who don’t actually have one. He called the tool’s accuracy “quite impressive.”
Researchers tested the system on 98 ears, in children older than 18 months who were about to undergo surgery at Seattle Children’s Hospital. Half were having ear tubes implanted, so doctors could tell exactly how much fluid was present to compare with the smartphone results. The system detected fluid as well or better than specialized acoustic testing devices, the team reported Wednesday in the journal Science Translational Medicine.
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