What’s in a Cough?

Scientists have developed a new technique to reliably detect pneumonia in children using only a microphone and simple computer.  Portable and cheap, this technology could improve healthcare for children in poor, remote areas.

According to the World Health Organization (WHO), pneumonia is the leading cause of death among children worldwide. As it is easily treatable with antibiotics, pneumonia is most prevalent in developing nations with limited healthcare resources, particularly in Asia and sub-Saharan Africa.

Pneumonia causes a distinctive cough, and a trained professional can tell the difference by listening. But trained doctors are spread far too thin, so WHO has developed a set of criteria that community workers can use to diagnose pneumonia on their own.

However, the WHO test’s accuracy is limited and it has a high rate of false positives, meaning that children are often misdiagnosed with pneumonia when they have some other respiratory illness. Where supplies of antibiotics are limited and precious, making the correct diagnosis can make all the difference.

The research team, led by Dr. Udantha Abeyratne from the University of Queensland in Australia, recorded hundreds of coughs from children with and without pneumonia at the Sardjito Hospital of Gadjah Mada University in Indonesia. Working with pediatric respiratory technicians, they classified the coughs as either pneumonic or non-pneumonic, and then trained a computer algorithm to tell the difference.

The result is an audio-only test that can detect pneumonia with more than 90 percent accuracy. What’s more, their test has a very low false-positive rate, making it more accurate overall than the WHO test.

"Our results indicate the feasibility of taking a cough-centered approach to the diagnosis of childhood pneumonia in resource-poor regions," the study authors concluded. "The technology, in its simplest version, will require between five and 10 cough sounds and will automatically and immediately provide a diagnosis without requiring physical contact with patients."

Although the technology currently only exists in the lab, it should soon be converted for widespread use in the developing world. Requiring only a microphone and a small computer, it would make an ideal candidate for a smartphone app. Smartphones are small, cheap, portable, have a long battery life, and already come equipped with the requisite microphone, data storage, and processing power.

Making Healthcare Mobile

Abeyratne’s team aren’t the only ones looking to use smartphones as health tools in the developing world. Dr. Shwetak Patel, a researcher at the University of Washington in Seattle, has invented a way to use a smartphone’s built-in microphone to measure a patient’s lung function.

Normally, doctors use a device called a spirometer to measure lung function. A patient blows into a tube and small turbines measure the amount of airflow. Spirometers are used to help doctors monitor patients with asthma, cystic fibrosis, allergies, and other respiratory ailments.

Patel’s new iPhone app, called SpiroSmart, is able to use the phone’s microphone to detect how a patient’s vocal resonance changes as he or she breathes out, effectively measuring the volume of air exhaled. In clinical tests, SpiroSmart proved to be accurate to within five percent of the current gold standard for spirometers.

Although the app isn’t currently available, Patel hopes to get SpiroSmart approved by the FDA for use as a medical device by the end of the year. By allowing patients to regularly monitor their own respiratory conditions using their phones, this technology could cut costs and allow for more routine testing and treatment at home.

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