Researchers use smartphone data for early detection of Alzheimer’s

Researchers from DZNE and Otto von Guericke University Magdeburg have identified individuals at increased risk of dementia using mobility data recorded during a smartphone-based wayfinding task on the university campus. The findings, reported in the journal PLOS Digital Healthdemonstrate the potential of smartphone data, collected in conditions close to daily life, for the early detection and monitoring of Alzheimer’s disease. The study included 72 adults; about a third of them have subjective cognitive decline (SCD), a condition that is a known risk factor for dementia.

Alzheimer’s disease usually develops unnoticed over the years and eventually leads to dementia. To date, there is no cure.

Currently, Alzheimer’s disease is often treated too late to ensure effective therapy. Even the new antibody drugs that are much talked about at the moment only work if given early. So we need to be able to diagnose the disease earlier, when the symptoms are still mild. This requires advances in diagnostics.”

Dr. Anne Maass, research group leader at DZNE and visiting professor at the University of Magdeburg

Together with colleagues, she now tested a new approach for assessing problems in spatial navigation, as one of the first potential symptoms of Alzheimer’s disease.

App in use

“Our research is based on a kind of treasure hunt where participants had to find pre-specified places of interest. For this they used a smartphone equipped with a special app that we developed,” explains Dr. Nadine Diersch out. The neuroscientist started the research project at DZNE several years ago and currently works in the private sector, but is still affiliated with DZNE as a visiting researcher. “We found that certain app data makes it possible to reliably identify people at increased risk of dementia,” she says. “This shows that digital technologies, such as mobile apps, offer completely new possibilities to assess cognitive functioning under realistic, accessible conditions. In the future, this could help detect subtle cognitive changes and thus harbingers of dementia earlier than today.”

“treasure hunt” on campus

A total of 72 women and men between their mid-twenties and mid-sixties took part in the study. Of the 48 elderly individuals, 23 were diagnosed as SCD patients. People with this condition experience a loss of mental capacity, which, however, cannot be detected by conventional neuropsychological tests. These individuals do not inevitably develop dementia. However, they have been shown to be at increased risk. All study participants were instructed to independently find various buildings on the medical campus of the University of Magdeburg, guided by the app, while their movement patterns were tracked by GPS. “Our participants had similar knowledge of the campus area and all had experience using smartphones. We also practiced with the app in advance,” explains Jonas Marquardt, first author of the study and PhD candidate in Anne Maass’s research group.

Assess the sense of direction

During the task, which each study participant had to perform individually, five buildings had to be visited one after the other along a route of approximately 800 meters. The app acted as a pacemaker: it showed a map with the current position and the next destination, including a photo of it. However, the card disappeared as soon as a participant started walking. “The participants had to memorize the layout of the streets, their position and their destination, and then follow their sense of direction and spatial memory,” says Marquardt. “If they were lost, they could press a help button in the app. The map, their position and their destination would then briefly appear again.” The researchers used the GPS data to generate individual mobility profiles and other information.

Suspicious stops

In most cases, participants reached the five destinations in less than half an hour. “In general, the younger participants performed better. They walked shorter distances on average and generally did not use the assistance function as often as the older ones,” says Marquardt. The differences between elderly people with and without SCD were mainly reflected in the number of so-called orientation stops. Jonas Marquardt explains: “Older adults with SCD stopped briefly while walking, presumably to orient themselves, more often than older adults without SCD. In fact, we were able to identify participants with SCD based on this parameter.”

Early detection perspectives

Until now, it is unclear why people with SCD differ in this regard. “We found that they hesitate more, especially at intersections. This indicates that certain decision-making processes are being changed. However, the data is not yet conclusive,” explains Nadine Diersch. “Nevertheless, the results of our study are a promising proof of concept. They show that smartphone data can help detect subtle signs of cognitive decline in real-world contexts.” The scientist sees this as an opportunity for early detection and early treatment of dementia: “I can imagine that such apps will be used in the future to identify people at risk and then decide whether further testing or therapy at all is needed.”