A five-minute scan of blood vessels in the neck during mid-life could become part of future dementia screening, researchers have suggested.
If confirmed in larger studies, the scan - which predicts cognitive decline 10 years before symptoms appear - could become part of routine screening for people at risk of developing dementia.
The research, which is being presented at the American Heart Association Scientific Sessions conference in Chicago, was led by University College London (UCL).
Researchers said that as the heart beats, it generates a physical pulse which travels around the body.
Healthy, elastic vessels near the heart usually diminish the energy carried by this pulse by cushioning each heartbeat, preventing the pulse from reaching delicate blood vessels elsewhere in the body.
Factors like ageing and high blood pressure cause stiffening of these blood vessels, however, and may diminish their protective effect.
As a result, a progressively stronger pulse can travel deep into the fragile vessels which supply the brain.
Over time, this can cause damage to the small vessels of the brain, structural changes in the brain’s blood vessel network and minor bleeds known as mini strokes, which all may contribute to the development of dementia.
The study saw the team analyse a group of 3,191 middle-aged volunteers who were given an ultrasound in 2002, which measured the intensity of the pulse travelling towards their brain.
Over the next 15 years, they monitored the participant’s memory and problem-solving ability.
Participants with the highest intensity pulse (top 25%) at the beginning of the study were around 50% more likely to exhibit accelerated cognitive decline over the next decade compared to the rest of the participants.
This difference was present even after adjustments for possible confounding factors, such as age, body mass index (BMI), blood pressure and diabetes, and whether participants had other heart conditions.
Researchers said cognitive decline is a noticeable and measurable reduction in cognitive abilities including memory, language, thinking and judgment skills.
Cognitive decline is often one of the first signs of dementia, but not everyone who shows signs of cognitive decline will go on to develop dementia.
The team now plans to use MRI scans to check if these individuals also display structural and functional changes within the brain which may explain the changes in cognitive abilities.
They also plan to test whether the scan improves predictive "risk scores" for dementia which already exist.
Vascular dementia is one of the most common types, caused by a problem with blood supply to the brain which damages or kills brain cells.
Research suggests controlling blood pressure and cholesterol, having a healthy diet, regular exercise and not smoking can all help to stave off dementia.
Dr Scott Chiesa, post-doctoral researcher at UCL, said: "These findings demonstrate the first direct link between the intensity of the pulse transmitted towards the brain with every heartbeat and future impairments in cognitive function.
"It’s therefore an easily measurable and potentially treatable cause of cognitive decline in middle-aged adults which can be spotted well in advance."
Professor Metin Avkiran, associate medical director at the British Heart Foundation, which co-funded the research, said: "Our beating heart is what keeps us alive, but we also need healthy blood vessels to maintain a healthy blood supply to all organs, including the brain.
"This test may provide a new way to identify people at risk of cognitive decline long before they display any noticeable symptoms.
"What we need now is further research, for example to understand whether lifestyle changes and medicines that reduce pulse wave intensity also delay cognitive decline."