Publications

Known risk factors for heart disease, an individual’s genetic makeup as well as other health factors, are thought to contribute to someone’s risk of developing Alzheimer’s disease (AD). Researchers have put together a scoring system that uses these risk factors in midlife to calculate someone’s risk of developing Alzheimer’s disease dementia in the future. This is known as a CAIDE score.

The authors used data from the first 210 PREVENT participants from the West London group. The participants were split into two groups based on their CAIDE score and each participant had an MRI scan to look at their brain at two time points, their initial visit and then two years later. The researchers found that the group of participants with a CAIDE score of 7 and above showed more overall shrinkage in their brain after two years compared to people with a lower score.

The authors therefore were able to demonstrate that there is an association between CAIDE score and brain volume and that individuals with a higher CAIDE score in midlife are already showing signs of brain changes. It also provides evidence that using an MRI scanner to image individuals thought to be at risk every few years and measuring brain changes, or lack thereof, may be a good way to track disease progression, or how well an intervention is working.

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.