Not Being Able To Find Your Way May Indicate Early Signs Of Alzheimer's Disease

It is possible to identify a person's risk to Alzheimer's disease by just seeing how people navigate. Scientists find that navigational skills tend to deteriorate much before other symptoms of Alzheimer's are manifested.

Navigation problems start early in those who have Alzheimer's, which is due to the build up of amyloid plaques and tau tangles, apart from other signs of shrinkage in the brain.

Researchers have used a virtual maze navigation study to check on people who have problems with route learning and cognitive map building, involving the caudate and the hippocampus. They can be located in preclinical Alzheimer's patients. Researchers have examined two distinct forms of spatial representation, including egocentric navigation, in which people search for landmarks in well-worn routes, and allocentric navigation, in which people understand "big picture" environments, leading to the creation of mental maps.

When researchers separated volunteers into three groups, they were tested for their ability to find their way through a virtual maze that had a number of interconnected hallways that showed four virtual wallpaper patterns and 20 landmarks. In 20 minutes they had to find their route through the maze and were asked to recreate their way back to landmarks.

"People with cerebrospinal markers for preclinical Alzheimer's disease demonstrated significant difficulties only when they had to form a cognitive map of the environment---an allocentric, place-learning navigation process associated with hippocampal function," said Denise Head of Washington University and one of the researchers involved in the study. "The same preclinical Alzheimer's disease group showed little or no impairment on route learning tasks----an egocentric navigation process more closely associated with caudate function."

Those who suffer from preclinical Alzheimer's disease exhibit trouble learning about their environment, so they may require more training to learn about new surroundings. However, they still have enough data which can help them to use a cognitive map as well as other people who are not afflicted with preclinical Alzheimer's.

The findings were published in the April 2016 issue of the Journal of Alzheimer's Disease.