Predicting dementia

In the future, physicians may be able to identify dementia much earlier than they can today because a computer algorithm will be able to predict from brain scans how our memory is going to develop.

If a physician diagnoses dementia at present, the disease is already quite advanced. An MRI scan of the brain shows how the brain tissue has diminished. However, research has shown that dementia also affects the brain in other ways. The structure of the brain changes. Neural pathways connect parts of the brain less efficiently, and it also seems that changes take place in the functional connections: the links in brain activity that normally exist between different areas of the brain.

‘Healthy people with a genetic predisposition to dementia have on average different functional connections in their brains than people without that genetic predisposition,’ says Serge Rombouts, researcher at Leiden University’s Institute of Psychology and Leiden University Medical Center (LUMC). ‘The connections between some brain areas are less strong, while other connections are stronger. We’re investigating whether those changes are correlated with developing the disease.’

Patterns in data

The research study by Rombouts and his colleagues is following different groups of healthy people, including those with a predisposition to dementia. The participants are given regular brain scans, and, as soon as the disease is diagnosed, the researchers will be able to look back over the scans made in previous years. They are hoping to find changes that correlate with the disease, and also to investigate whether they could have predicted the disease from these changes.

As it is currently not known which changes are important, this is rather like looking for a needle in a haystack. For instance, at least a thousand brain areas are functionally linked with each other, resulting in half a million functional connections. The same applies for anatomical connections. The researchers therefore select which areas are probably important, on the basis of the knowledge they already have. They are also developing self-teaching algorithms: computer programmes that train themselves to recognise patterns in this vast quantity of data, so that they can pick out the relevant changes in the scans.

Predictions in the future

However, Rombouts warns that much still needs to be done before computers can help us predict how our memory will develop on the basis of brain scans. ‘The results of this study are at least true for the group of people that we’ve followed. But to validate the results, we need to study many more groups. Another problem is that each type of scanner has its own technology. The technologies are equally good, but the differences between them mean that the results of the various types of scanners can’t be directly compared. The algorithm must be able to deal with this, and to give a reliable analysis for each scanner.’

The technology being developed by the Leiden researchers is not only relevant for dementia. ‘The method we’re developing for analysing brain scans can perhaps help with diagnosing other conditions,’ says Rombouts. ‘For instance, neurological disorders, such as Parkinson’s disease, or psychiatric disorders, such as depression. In the long run, it might even be possible to use this method to predict the treatment effects of various drugs.’

In addition to Leiden University and LUMC, other organisations involved in the research are Erasmus MC, VUmc Alzheimer Centre and the Centre for Human Drug Research.

Institute of Psychology (Methodology & Statistics unit)
Leiden Institute for Brain and Cognition (LIBC)
LUMC
Erasmus MC
VUmc Alzheimer Centre
Centre for Human Drug Research