A quick neck scan could spot people at risk of dementia years before symptoms appear, researchers claim.

An international team of experts, led by University College London (UCL), has used ultrasound to view blood vessels in the necks of more than 3,000 people, as well as monitoring them over the next 15 years.

They found people with the most intense pulses were more likely to suffer cognitive decline over the next decade than other participants.

The experts say more intense pulses could damage the small vessels of the brain, and create structural changes in the brain's blood vessel network and minor bleeds known as ‘mini-strokes’.

Those with the highest intensity pulse at the beginning of the study were about 50 per cent more likely to show accelerated cognitive decline over the next decade - about an extra one to one-and-half years of decline.

The tests could provide a new way to identify people at risk of developing dementia, allowing for earlier treatments and lifestyle interventions.

“Dementia is the end result of decades of damage, so by the time people get dementia it's too late to do anything,” said Dr Scott Chiesa from UCL.

“What we're trying to say is you need to get in as early as possible, identify a way to see who's actually progressing towards possibly getting dementia and target them.”

The next phase of the research will use MRI scans to check if participants also display structural and functional changes within the brain that could explain their cognitive decline.

The study is being presented at the AHA Scientific Sessions conference in Chicago.