What doctors say and what patients hear is not always the same thing. For proof, look no further than patients’ Google search histories.

That’s what a group of researchers from the University of Pennsylvania did.

Combining Google search data with electronic medical records, they found that a patient who had been told of having had “a walnut-size fibrous tumor” promptly went home and searched “How big is a walnut?” and “What is a fibrous tumor?”

Clearly something was lost in communication.

“Even something as banal as how big a walnut is might make us rethink how we explain things to our patients,” said Jeremy Asch, a co-author of the study and an innovation strategist in the Penn Medicine Center for Digital Health.

The study, which published in February, involved 116 patients from a hospital emergency room who agreed to share their Google search histories. Researchers analyzed that data to see what patients searched in the weeks and days before coming to the hospital, and compared it with medical records to see if there were any patterns.

They found that health-related searches doubled during the week before patients came to the emergency room. On a daily basis, about 6 percent of all Google searches are health-related, Asch said. But in the week before a patient visits the hospital, their rate was upward of 12 percent.

“If we can look at this and see what patients are searching for, it could help us anticipate demand and the patient’s need for care,” Asch said.

Knowing which symptoms and concerns patients are Googling before they arrive in the emergency room can help doctors have more comprehensive conversations with them. If they searched fainting spells, but don’t mention that during a visit about high blood pressure concerns, maybe the doctor can bring it up, Asch said.

The study found more than half the searches patients conducted before coming to the emergency room were related to the reason for their visit. For instance, someone searched “how to relieve sinus pressure,” and later arrived at the hospital with a chief complaint of “headache.”

And while doctors often worry about patients Googling symptoms and jumping to the worst possible conclusions, the researchers found that was rarely the case.

“Most people did search pretty accurately for what they’re complaining about and not down that rabbit hole of ‘is it cancer or a brain tumor,’ ” Asch said.

It can also be helpful to know what patients search after leaving the hospital, potentially to rectify miscommunications like the walnut-size tumor. Shelled? Unshelled?

Patients sometimes feel embarrassed asking doctors questions directly, Asch said, but the study shows many are open to letting doctors know what they have searched for, and including that information in their electronic health record. That could give medical professionals deeper insight into someone’s condition.

“We could track digital info the same way we study DNA, and understand how someone's daily life choices interact with health,” Asch said.

There are still many questions to be answered before search data can be usefully integrated into medical care. Privacy issues are always important, though if the data were made part of the electronic medical record, it would get the same protections as current medical information, Asch said.

Another hurdle is the time it would take doctors to go through mounds of search history data. Researchers hope machine learning tools could be used instead, identifying searches of concern and alerting doctors when needed.

The search data might also be used to create a timeline of symptoms for patients, reminding them of events throughout the year they might otherwise forget to mention during an annual checkup.

With more people Googling symptoms online and asking about medical conditions in Facebook groups, there is a lot of potential, Asch said.

“As the way we socially communicate changes,” he said, “it’s exciting to figure out how we can use all this data to better serve our patients.”