Some of the earliest brain regions to be affected by Alzheimer’s disease are thought to be those involved in memory and spatial orientation. Researchers led by PREVENT Co-Chief Investigator Prof Karen Ritchie were interested in how the PREVENT cohort performed on  tasks involving particular orientation skills. The ‘4 Mountains Task’ is used to measure navigation through allocentric space (person-independent, relating to the location of particular objects in relation to other objects in space). The ‘Virtual Supermarket Task’ involves orientation of egocentric space (person-dependent, relating to the location of objects in space relative to one’s own body position).   

They found that participants with a higher ‘Dementia Risk Score’ (calculated from a combination of known risk factors such as genetics and cardiovascular health) scored significantly lower overall on the ‘4 Mountains’ allocentric orientation task. There was no significant association between Dementia Risk Score and performance on the ‘Virtual Supermarket’ test of egocentric space.

These findings would support the idea that the earliest brain changes associated with Alzheimer’s disease may be able to be detected through specific tests of spatial orientation. Developing behavioural tests that are sensitive to these very earliest changes could be vital in supporting earlier identification of disease burden, long before symptoms become apparent. They could also prove important in offering a way of measuring the effectiveness of future early interventions, including drug trials. 

This investigation included only a small initial population of what will form the eventual 700-strong PREVENT cohort. The researchers are keen to repeat this analysis once more participants have completed the spatial processing tasks.