'Idle brain' test can detect dementia nine years before diagnosis

The new test, which analyses connections in the brain when it is in 'idle mode', is 80 per cent accurate, say researchers

Scientists have developed a new method of detecting the development of dementia up to nine years before it is diagnosed. Getty Images

Scientists have developed a new method of detecting dementia up to nine years before it is diagnosed by analysing connections in the brain when it is in “idle mode”.

The test, developed by researchers from Queen Mary University of London, is 80 per cent accurate and better at detecting the condition than memory tests or measurements of brain shrinkage.

The researchers said 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 show.

The team, led by Prof Charles Marshall, looked at MRI brain scans from more than 1,100 people from UK Biobank, a database containing genetic and health information from 500,000 people in Britain.

The researchers developed a model that could predict which people in this group would go on to be diagnosed with dementia.

They examined the patterns of connections in a brain network called the default mode network (DMN). This kicks in when the brain is in idle mode – when the mind wanders and is not focused on a particular task.

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 did not go on to develop dementia, the findings showed.

Prof Marshall, who led the research team within the Centre for Preventive Neurology at Queen Mary’s Wolfson Institute of Population Health, told The National the test could be the first step towards a cure for the disease.

He said no treatment yet exists to prevent dementia, but this might help researchers identify one.

"At the moment we would be looking to use it as a way to identify people at high risk that could go into trials of treatments that might stop the development of dementia," he said.

He added: “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.”

In a statement to The National, Dr Richard Oakley, associate director of research and innovation at the Alzheimer's Society, said the test could provide a non-invasive way of identifying people at risk of developing dementia, when they are most likely to benefit from lifestyle changes that could potentially reduce their risk.

“While we have new disease-modifying treatments for Alzheimer’s disease on the horizon, they are only suitable for people in the early stages … so early and accurate diagnosis through tools such as this are vital," he added.

But he said further research was required involving diverse groups of people of different ages and ethnicities to fully understand the benefits of the method.

On a practical level, the NHS does not have capacity to roll out early diagnostic tools like this, which are expensive, require specialist staff and can be difficult to access for many people in the UK.

“With one in three people born today going on to develop dementia, we need to see urgent investment in the NHS to improve dementia diagnosis,” Dr Oakley added.

Tara Spires-Jones, 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”.

The findings have been published in the journal Nature Mental Health.

Last year a study revealed a list of 11 risk factors which can “strongly predict” whether a person will develop dementia in the following 14 years.

The 11 factors are age, education, a history of diabetes, a history of depression, a history of stroke, parental history of dementia, levels of deprivation, high blood pressure, high cholesterol, living alone and gender.

Researchers also examined these risk factors alongside whether or not people carried the APOE gene, which is a known risk factor for dementia.