GaitTrack App Turns Cellphone into Medical Monitor for Heart and Lungs

The new GaitTrack app, developed by researchers at the University of Illinois at Urbana-Champaign and Chicago, can convert any cellphone into a sophisticated medical monitor for your heart and lungs.

Especially useful for patients suffering from chronic diseases, GaitTrack uses eight motion parameters to perform a detailed analysis of a person's gait, or walking pattern. It can tell physicians a lot about a patient's cardiopulmonary, muscular and neurological health.

The unique app, described in the journal Telemedicine and e-Health, is unlike any normal fitness app currently on the market.

"Fitness apps and devices are tuned for healthy people," lead researcher Bruce Schatz, affiliated with the Institute for Genomic Biology at the University of Illinois, said in a statement. "They cannot accurately measure patients with chronic disease, who are the biggest medical market. A pedometer is not a medical device. But a cheap phone with GaitTrack software is."

According to Schatz, gait is sometimes called the "sixth vital sign" - after temperature, blood pressure, heart rate, respiratory rate and blood oxygen level. Gait speed involves several systems of the body working together in coordination, so changes in gait can be a sign of trouble in one or more systems.

Patients with chronic disease tend to walk with shorter, more careful strides, or shuffle across the floor, making it difficult to measure their gait with a typical pedometer. For those with heart and lung disease, such as congestive heart failure, chronic obstructive pulmonary disease (COPD) and asthma, doctors often use an assessment called the six-minute walk test. GaitTrack offers an easier way of running this test.

The Illinois team used GaitTrack to administer six-minute walk tests to 30 patients with chronic lung disease and found that it was a cheaper, more accurate monitor compared to medical accelerometers. What's more, they discovered that analysis of the gait data could predict lung function with 90 percent accuracy, within an age group.

Schatz envisions people constantly running the GaitTrack app while carrying their phones as a sort of early warning system if it should detect any concerning changes in gait.

"Population health measurement is the key to making health care viable. If you could just measure what people were doing all the time, then you could get enough information to make rational decisions," Schatz concluded.