First-of-its-kind test can predict dementia up to 9 years before diagnosis, scientists say

RESEARCHERS have developed a first-of-its-kind test that could predict dementia up to nine years before a diagnosis – and with 80 per cent accuracy.

The new test is more accurate than other commonly used methods, like memory tests or measurements of brain shrinkage, researchers claim.

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It involves analysing network of connections in the brain when it’s in “idle mode” to look for very early signs of the condition.

The technique has the “potential to fill an enormous clinical gap” by identifying people who are at risk of dementia and treating them before symptoms start to show, scientists said.

The team at Queen Mary University of London – lead by Professor Charles Marshall – developed the test by analysing scans to detect changes in the brain’s ‘default mode network’ (DMN).

The DMN connects regions of the brain to perform specific cognitive functions and is the first neural network to be affected by Alzheimer’s disease. 

It kicks in when the brain is in ‘idle mode’ – for example, when the mind wanders and isn’t focused on a particular task.

Researchers examined the functional MRI (fMRI) scans of 1,100 volunteers from the UK Biobank study, a large-scale biomedical database containing genetic and health information from half a million Brits.

They used the scans to estimate how connected the ten regions of the brain that make up the DMN were.

The team then developed a model they claimed could predict which people in this group would go on to be diagnosed with dementia.

Among the 103 people who had dementia, 81 had brain scans between five months and 8.5 years before being officially diagnosed.

Their brain scans showed less ‘connectivity’ in the default mode network compared with those who didn’t go on to develop the brain robbing disease, findings published in Nature Mental Health showed.

The findings showed that the model was able to accurately predicted onset of dementia up to nine years before an official diagnosis was made, with more than 80 per cent accuracy.

The model could also predict exactly how long it would take that diagnosis to be made, with a two-year margin of error.

Researchers also examined whether changes to the DMN might be caused by known risk factors for dementia.

Genetic risk for Alzheimer’s disease was strongly associated with connectivity changes in the DMN.

They also found that social isolation was likely to increase risk of dementia through its effect on connectivity in the DMN.

‘ENORMOUS POTENTIAL’

Prof Marshall, who led the research team within the Centre for Preventive Neurology at Queen Mary’s Wolfson Institute of Population Health, said: “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.

“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.

“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.”

Lead author Samuel Ereira, from the Centre for Preventive Neurology, Wolfson Institute of Population Health, said: “Enormous potential exists to apply these methods to different brain networks and populations, to help us better understand the interplays between environment, neurobiology and illness, both in dementia and possibly other neurodegenerative diseases.

“fMRI is a non-invasive medical imaging tool, and it takes about six minutes to collect the necessary data on an MRI scanner, so it could be integrated into existing diagnostic pathways, particularly where MRI is already used.”

Others not involved in the research said the dementia test needs to be further studied and noted that fMRIs aren’t widely available.

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”.

He added: “On a practical level, the NHS does not yet have capacity to roll out early diagnostic tools such as this.

“MRI scanners are expensive, require specialised staff, and can be difficult to access for many people in the UK.”

Tara Spires-Jones, FMedSci, president of the British Neuroscience Association and professor in the UK Dementia Research Institute at the University of Edinburgh, said that while this type of brain scan is useful, they are “not widely available nor are they perfect at predicting who will go on to develop dementia”.

It comes after research found that routine free check ups offered to Brits after the age of 40 could map your 10-year risk of dementia and other diseases.

US scientists also said your spouse likely to spot Alzheimer’s quicker than your doctor.