Scientists may be one step closer to a cure for Alzheimer’s after pinpointing subtle telltale signs in the brains of people most likely to get the disease.
The memory-robbing illness has long been believed to be caused by a build-up of the proteins amyloid and tau in the brain.
While most ageing brains have some level of both these proteins, a significant clump of them can form plaques and tangle — and this is thought to be behind dementia symptoms.
But now, Canadian researchers have discovered an intriguing brain change that could happen long before the plaques are seen on scans — but indicate they’re likely to develop.
The team, from McGill University in Montreal, found those with reduced electrical activity in specific areas of the brain are more likely than others to go on to develop dementia-causing plaques.
While most ageing brains have some level of both these proteins, a significant clump of them can form plaques and tangle — and this is thought to be behind dementia symptoms
Alzheimer’s disease is the most common cause of dementia. The disease can cause anxiety, confusion and short-term memory loss
In the study, the scientists analysed two separate brain scans of more than 100 volunteers — all with a family history of Alzheimer’s.
The first tracked the locations of proteins in the brain, with the second recording the brain activity in these regions.
They found those with higher levels of amyloids displayed brain hyperactivity — higher frequency brain activity.
By comparison, those with both amyloids and tau plaques in their brain showed signs of hypoactivity — when brain activity slows.
Cognitive tests also showed that volunteers with higher levels of both proteins were more likely to be suffering with memory loss and shorter attention spans.
Writing in the journal Nature Neuroscience, the scientists said their findings suggest that higher levels of these proteins may lead to altered brain activity that can be spotted before cognitive symptoms appear.
Researchers now hope to re-scan the same 104 participants to track whether the accumulation of these two proteins does further slow brain activity.
They also aim to decipher whether this can accurately predict cognitive decline.
Jonathan Gallego Rudolf, an expert in neuroimaging and the study’s lead author said: ‘Our study provides direct evidence in humans for the hypothesized shift in neurophysiological activity, from neural hyper- to hypo-activity, and its association with longitudinal cognitive decline.
‘These results parallel findings from animal and computational models.
‘They also contribute to the advancement of our understanding of the pathological mechanisms underlying the preclinical stage of Alzheimer’s disease.’
Around 944,000 in the UK are thought to be living with dementia, while the figure is thought to be around 7million in the US.
Alzheimer’s affects around six in 10 people with dementia.
Memory problems, thinking and reasoning difficulties and language problems are common early symptoms of the condition, which then worsen over time.
Dementia cases are expected to sky-rocket in the coming years, making a cheap screening tool vital to get to grips with the challenge.
Alzheimer’s Research UK analysis found 74,261 people died from dementia in 2022 compared with 69,178 a year earlier, making it the country’s biggest killer.
It comes as fresh research yesterday suggested that diets rich in flavonoids — plant compounds found in the likes of tea, red wine, berries and dark chocolate — could substantially reduce the risk of the incurable disease.
Scientists believe they could have a protective effect on brain cells, helping to block the build-up of beta-amyloid plaque.
Researchers from Queen’s University Belfast analysed dietary data from more than 120,000 UK adults, aged between 40 and 70 over six years.
They found consuming six additional servings of flavonoid-rich foods per day, in particular berries, tea and red wine, was associated with a 28 per cent lower risk of dementia.