Waterloo researchers have used cell phones equipped with a GPS to prove there is a link between the geographical area a person covers in daily life and dementia in older adults.

The groundbreaking study compared the distance healthy older adults travelled on a daily basis to that of those living with Alzheimer’s disease. Adults with mild-to-moderate Alzheimer’s disease showed a significantly smaller life space than their healthy counterparts.

What is life space?

Life space, defined as the area a person travels within a specific time period, has long been thought to be an indicator of mental decline, but until now, has never been reliably documented, said Eric Roy, a professor in the Faculty of Applied Health Sciences, who co-led the study with Pascal Poupart, a professor in the Faculty of Math. The study is a collaboration between Waterloo researchers and Dr. Sandra Black of the Sunnybrook Research Institute in Toronto.

Eric Roy, Pascal Poupart and James Tung

Researchers have developed software for tracking and monitoring the mental decline in Alzheimers patients. Foreground Eric Roy, background right Pascal Poupart, background left James Tung.

“Life space provides a measure of how comfortable people are moving around in their environments. It is one of the more subtle indicators of the development of a dementia,” said Roy.

Traditionally, measurements of life space have relied on questionnaires asking people how far afield they ventured when they left their homes. The biggest problem with this approach is the inherent dependence on people’s memories, especially those thought to be in the early stage of dementia.

“The reliability and accuracy of these self-report methods is questionable. We wanted to try and do something that was an objective measure. Using GPS on smartphones was a very convenient way of doing that,” said James Tung, a postdoctoral fellow on the project.

But for both Tung and Roy, the study is about more than just using GPS to link life space and mental decline— it’s about paving the way for new clinical practices.

Clues to dementia onset

“Years before the dementia shows up people may show changes in the size of their life space. A shrinking life space could be a warning sign something is wrong,” said Roy.

If clinicians used GPS tracking to monitor individuals at risk for Alzheimer’s disease, they could ideally make earlier diagnoses and recommend disease slowing mechanisms.

“We want to make sure people who are at risk, do things to reduce their risk. The disease could be delayed by making lifestyle changes like being more physically active or being more socially involved,” said Tung.

While the potential uses for GPS as a tool to detect dementia are still in their infancy, Roy and Tung are sure of one thing.

“There are strong practical applications for this approach to looking at dementia. It could change the way we think about disease onset.”