Researchers say changes in folks' driving patterns could be an early signal of cognitive decline.

“We found that using a GPS data tracking device, we could more accurately determine who had developed cognitive issues than looking at just factors such as age, cognitive test scores and whether they had a genetic risk factor related to Alzheimer’s disease," explained study lead author Ganesh Babulal of Washington University School of Medicine in St. Louis, Missouri.

His team reported their findings Nov. 26 in the journal Neurology.

As Babulal explained in a journal news release, the "early identification of older drivers who are at risk for accidents is a public health priority, but identifying people who are unsafe is challenging and time-consuming."

What if simply tracking everyday behaviors, such as driving, could help?

In the new study, the St. Louis team first enrolled 56 people already diagnosed with mild cognitive impairment (MCI), which can sometimes be a precursor to Alzheimer's disease.

They also enrolled another 242 people of similar age but without such diagnoses. Together, the group averaged 75 years of age, and everyone said they drove at least once a week.

All participants also took standard tests for thinking skills, and all agreed to having special GPS tracking installed in their vehicles to monitor their driving.

At first, driving patterns between cognitively impaired and non-impaired people seemed similar, the researchers said.

However, that began to change over time: People with MCI began to drive less frequently, drove less at night, and there was less variance in where they drove, compared to folks whose cognition was not impaired.

Adding that information to other data on a person's age, other demographics, cognitive test scores and whether or not they had a gene associated with Alzheimer’s, accuracy in spotting cognitive decline rose to 87%, the researchers said.

“Looking at people’s daily driving behavior is a relatively low-burden, unobtrusive way to monitor people’s cognitive skills and ability to function,” Babulal said. “This could help identify drivers who are at risk earlier for early intervention, before they have a crash or near miss, which is often what happens now. Of course, we also need to respect people’s autonomy, privacy and informed decision-making and ensure ethical standards are met."