Global positioning system (GPS) devices are everywhere these days—in cars, cell phones, dog collars—and now, even in asthma inhalers. Researchers from the University of Wisconsin–Madison recently launched a study using GPS devices to monitor where and when patients use their inhalers, a technology they hope will uncover unrecognized triggers of asthma symptoms.

Scientists have long known that environmental factors such as pollen, cigarette smoke, and air pollutants aggravate symptoms of asthma, such as wheezing, coughing, and shortness of breath. But the leader of the study David Van Sickle, an epidemiologist at the UW School of Medicine and Public Health says it's likely there are unknown environmental culprits. Figuring out exactly when and where asthma attacks occur can help pinpoint these aggravators, he adds.

Take, for instance, a string of asthma outbreaks that occurred in Barcelona, Spain in the 1980s, Van Sickle says. On 26 separate occasions between 1981 and 1989, hospital emergency rooms throughout the city were suddenly flooded with people having asthma attacks. Stumped by these mini asthma epidemics, researchers scoured hospital records and weather and pollution data for a suspect. 

It was not until some eight years after the initial episodes that they finally pegged the source: soybean dust kicked up by ships unloading soybeans in the city's harbor. As it turned out, the asthma attacks tended to be clustered near the harbor and occurred on days that ships unloaded soybeans. If the researchers had access to a better method for monitoring when and where people had symptoms—like GPS-outfitted asthma inhalers—chances are the mystery would have been solved much faster, Van Sickle notes.

Two months ago, Van Sickle and his colleagues began recruiting asthma patients ages 18 and over for a 50-person study using GPS devices to monitor inhaler use. They have provided each participant with a cell-phone-sized GPS device to attach to his or her inhaler; every time the patient uses the device, it relays a signal to the researchers' computer server indicating the time and location.

Using this data, Van Sickle's team has begun making maps and time logs to illustrate patterns of inhaler use. "Right now, we're trying to evaluate how well the system works," says Van Sickle, who is set to present early findings in mid-May at the American Thoracic Society Meeting in San Diego.

Image courtesy of David Van Sickle, University of Wisconsin School of Medicine and Public Health