Dementia test could predict disease 'nine years before diagnosis with 80% accuracy'

Human head scan, x-ray.
-Credit: (Image: The Image Bank)

Scientists report they have developed a new method that can anticipate dementia up to nine years before diagnosis, with an 80% accuracy rate.

This test focusses on analysing the 'network of connections' in the brain while it is in "idle mode", to recognise early signs of the condition. Queen Mary University of London researchers believe their method is more robust than memory tests or measurements of brain shrinkage, two frequently used diagnostic tools for dementia.

They propose this technique has the "potential to fill an enormous clinical gap" by determining people at risk of dementia and treating them before symptoms arise.

The study, which was led by Professor Charles Marshall, inspected brain scans from over 1,100 individuals from UK Biobank, a database offering genetic and health data from half a million UK residents.

They scrutinised the patterns of links within a brain network known as the default mode network (DMN), active when the brain is idle not fixated on a specific task.

The team formulated a model that could predict which members of this group would be diagnosed with dementia.

Out of 103 persons diagnosed with dementia, 81 had undergone brain scans between five months and 8.5 years before official diagnosis. The findings indicated that their brain scans displayed less connectivity in the default mode network compared to those who did not go on to develop dementia.

Prof Marshall, who spearheaded the research at Queen Mary's Wolfson Institute of Population Health, emphasised the importance of early detection: "Predicting who is going to get dementia in the future will be vital for developing treatments that can prevent the irreversible loss of brain cells that causes the symptoms of dementia."

He also noted the current advancements in identifying Alzheimer's disease: "Although we are getting better at detecting the proteins in the brain that can cause Alzheimer's disease, many people live for decades with these proteins in their brain without developing symptoms of dementia."

Prof Marshall expressed optimism about the new measure of brain function: "We hope that the measure of brain function that we have developed will allow us to be much more precise about whether someone is actually going to develop dementia, and how soon, so that we can identify whether they might benefit from future treatments."

The groundbreaking study has been documented in Nature Mental Health.

Dr Richard Oakley, associate director of research and innovation at Alzheimer's Society, said while the research was able to identify structural changes in the brain before dementia symptoms appear, more studies are needed "involving diverse groups of people of different ages and ethnicities to fully understand the benefits and limitations of this MRI scan as a diagnostic tool".

Tara Spires-Jones, FMedSci, president of the British Neuroscience Association and professor in the UK Dementia Research Institute at the University of Edinburgh, has stated that while these types of brain scans are beneficial, they are "not widely available nor are they perfect at predicting who will go on to develop dementia".

Don't miss the latest news from around Scotland and beyond - Sign up to our newsletter here.