Alzheimer’s disease usually develops unnoticed over years and eventually leads to dementia. To date, there is no cure.
In total, 72 women and men between the ages of their mid-twenties and mid-sixties participated in the study. Of the 48 older individuals, 23 were diagnosed as SCD patients. People with this condition perceive a loss of mental capacity, which, however, cannot be detected by conventional neuropsychological tests. These individuals do not inevitably develop dementia.
However, it has been shown that they are at an increased risk. All study participants were instructed to independently find several buildings on the medical campus of the University Magdeburg, guided by the app, while their movement patterns were tracked by GPS.
During the task, which every study participant had to perform individually, five buildings had to be visited in a row along a route of about 800 meters. The app served as a pacemaker: It displayed a map with the current position and the next destination, including a photo of it. However, the map disappeared as soon as a participant started walking.
The participants had to memorise the layout of the streets, their position and their destination, and then follow their sense of direction and spatial memory. If they got lost, they could press a help button in the app. The map, their position and their destination would then briefly reappear. The researchers leveraged the GPS data to generate individual mobility profiles and other information.
In most cases, the participants reached the five destinations in less than half an hour. Overall, the younger participants performed better. On average, they walked shorter distances and generally did not use the help function as often as the older ones.
The differences between the older adults with and without SCD were mainly reflected in the number of so-called orientation stops.
“Older adults with SCD briefly stopped during walking more often, presumably to orient themselves, than older adults without SCD. In fact, we were able to identify participants with SCD based on this parameter,” say the researchers.
So far it is unclear why people with SCD stand out in this regard.
“We found that they tend to hesitate more at intersections in particular. This suggests that certain decision-making processes are altered. However, the data are not yet conclusive,” the researchers say.
“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 realistic contexts.”
The study was led by the German Centre for Neurodegenerative Diseases (DZNE) and Otto von Guericke University Magdeburg.
