How Can VR Glasses Serve as a Diagnostic Tool for Dementia?

Path Integration

Subtle difficulties with orientation may be an early sign of Alzheimer’s disease, appearing even before standard memory tests detect any issue. This was suggested by a new study recently published in Science Advances.

The research team decided to test a new approach in detecting cognitive impairment that goes beyond conventional testing methods. The experts focused on assessing what is known as "path integration," that is, the ability to track and remember one’s position and direction of movement.

As clarified by study co-author Professor Thomas Wolbers, people use a part of the brain called the entorhinal cortex for this task. It contains a special type of neurons called grid cells. This brain region is affected by Alzheimer’s disease in its earliest stages, even before dementia symptoms appear. According to Wolbers, path integration is highly sensitive to grid cell dysfunction.

An important aspect for the researchers was also subjective cognitive decline (SCD). This is a condition in which a person feels that their memory is worsening, even though standard tests show no decrease in cognitive performance. According to Wolbers, people with SCD are known to have an increased risk of developing Alzheimer’s disease later in life. The study therefore included 102 individuals aged 55 to 89, comprising 70 healthy controls and 30 people with SCD.

Testing in a Digital Landscape

All participants first underwent conventional cognitive tests, in which they all achieved normal results. They then put on a VR headset and walked through a real physical space while simultaneously moving through a computer-generated environment.

As explained by study co-author Vladislava Segen, the only way to navigate was by relying on the brain’s navigation system —⁠ and this was precisely the ability the researchers aimed to test.

The participants followed a moving ball until they caught up with it and it stopped. They were then asked to turn toward the original starting point and indicate its presumed location. In addition, they had to align themselves with the direction they were facing at the beginning of their journey. The ball then continued to another stop, and the responses were repeated. Each participant completed about 70 trials. This allowed the researchers to collect extensive data on movement and orientation accuracy.

People with SCD Made More Errors

The study found that people with SCD consistently made larger errors during the navigation task and were less accurate in path integration compared with individuals without SCD. The orientation difficulties were not caused by movement dynamics —⁠ such as walking speed or looking down more often —⁠ but had cognitive origins.

According to the researchers, the poor performance among the SCD group may have stemmed from “memory leakage,” meaning the participants had trouble keeping track of the sequence of previous positions necessary to update their real-time location. The researchers believe this may be due to dysfunction of the grid cells responsible for creating the mental coordinate system of our surroundings.

“To determine your position in space while moving, you must continuously update it in your mind. This requires remembering previous positions and drawing from a mental history. In people with SCD, this type of memory was particularly poor. That is why we refer to it as memory leakage, and we believe it originates from functional impairments in the entorhinal cortex,” said Vladislava Segen.

Editorial Team, Medscope.pro

Source:

Segen V., Kabir R., Streck A. et al. Path integration impairments reveal early cognitive changes in Subjective Cognitive Decline, Science Advances 2025 Sep 5; 11 (36): eadw6404, doi: 10.1126/sciadv.adw6404.