Where do we go now? Direction-finding problems could be an early sign of Alzheimer's disease, a new study found.
Preclinical Alzheimer's disease reveals variations in the brain that are associated with its development. These changes can be identified by looking at biomarkers found in spinal fluids and the brain.
These biomarkers are involved in the buildup of brain plaques in the caudate and hippocampus. The two parts play roles in the development of cognitive maps and route familiarization.
A team of researchers from the Washington University enrolled participants with and without these biomarkers. They tested the participants' maze navigation abilities to predict who are predisposed to develop Alzheimer's disease.
"These findings suggest that navigational tasks designed to assess a cognitive mapping strategy could represent a powerful new tool for detecting the very earliest Alzheimer's disease-related changes in cognition," said senior author Denise Head, a psychological and brain sciences associate professor.
The study enrolled 42 clinically healthy individuals without the spinal fluid biomarkers as well as 13 clinically healthy individuals who tested positive for the biomarkers, which suggested they have preclinical Alzheimer's. The study also had 16 individuals who had behavioral symptoms of the disease's early stages.
The team tested all of the participants' ability with a virtual maze navigation test for approximately two hours. In particular, the researchers focused on two navigational abilities.
The first focused on how well the participants can understand and follow a pre-determined route. The second concentrated on their ability to develop and create a mental map of the environment.
The team found that the participants with spinal biomarkers had substantial problems in forming a mental map. However, the same individuals had "little to no impairment" when it comes to navigation-learning tasks.
In the study's first phase, the participants with biomarkers for preclinical Alzheimer's scored lower compared to clinically healthy individuals without the biomarkers.
They had a hard time learning objects' locations within the environment in relation to each other. However, they managed to resolve these difficulties during the next wayfinding tasks, enabling them to perform almost as good as the ones without the biomarkers.
"The spatial navigation task used in this study to assess cognitive map skills was more sensitive at detecting preclinical Alzheimer's disease than the standard psychometric task of episodic memory," added Head.
The study findings suggested that direction-finding tasks, which are designed to tap into a mental mapping strategy, could be a useful method for detecting the earliest cognitive changes related to the disease.
The study was published in the Journal of Alzheimer's Disease.
