Scientists could be a step closer to a cure for Alzheimer’s after identifying subtle telltale signs in the brains of people most likely to suffer from the disease.
This memory-destroying disease has long been believed to be caused by a buildup of the proteins amyloid and tau in the brain.
While most aging brains have some level of both proteins, a significant amount of them can form plaques and tangles, which is thought to cause the symptoms of dementia.
But now, Canadian researchers have discovered an intriguing brain change that may occur long before the plaques are visible on scans, but indicates they are likely to develop.
The team, from McGill University in Montreal, found that those with reduced electrical activity in specific areas of the brain are more likely than others to develop dementia-causing plaques.
While most aging brains have some level of both proteins, significant amounts of them can form plaques and tangles, which is thought to be behind the symptoms of dementia.
Alzheimer’s disease is the most common cause of dementia. The disease can cause anxiety, confusion and short-term memory loss.
In the study, scientists analyzed two separate brain scans of more than 100 volunteers, all with a family history of Alzheimer’s.
The first tracked the location of proteins in the brain, while the second recorded brain activity in those regions.
They found that those with higher levels of amyloid showed brain hyperactivity (higher frequency brain activity).
In comparison, those who had amyloid and tau plaques in their brains showed signs of hypoactivity (when brain activity decreases).
Cognitive tests also showed that volunteers with higher levels of both proteins were more likely to suffer from memory loss and shorter attention spans.
Writing in the diary Neuroscience of natureThe scientists said their findings suggest that higher levels of these proteins may lead to altered brain activity that can be detected before cognitive symptoms appear.
The researchers now hope to scan the same 104 participants again to track whether the buildup of these two proteins further slows brain activity.
They also aim to decipher whether this can accurately predict cognitive decline.
Jonathan Gallego Rudolf, a neuroimaging expert and senior author of the study, said: ‘Our study provides direct evidence in humans of the hypothesized shift in neurophysiological activity, from neuronal hyperactivity to hypoactivity, and its association with longitudinal cognitive decline.
‘These results parallel findings from animal and computational models.
‘They also contribute to improving our understanding of the pathological mechanisms underlying the preclinical phase of Alzheimer’s disease.’
It is estimated that around 944,000 people in the UK are living with dementia, while the figure stands at around 7 million in the US.
Alzheimer’s affects approximately six out of ten people with dementia.
Memory problems, thinking and reasoning difficulties, and language problems are common early symptoms of the disease, which then worsen over time.
Dementia cases are expected to skyrocket in the coming years, so an inexpensive screening tool is vital to meet this challenge.
An analysis by Alzheimer’s Research UK found that 74,261 people died from dementia in 2022, compared with 69,178 a year earlier, making it the country’s biggest killer.
This comes after new research suggested yesterday that diets rich in flavonoids – plant compounds found in foods such as tea, red wine, berries and dark chocolate – could substantially reduce the risk of the incurable disease.
Scientists believe they may have a protective effect on brain cells, helping to block the buildup of beta-amyloid plaque.
Researchers at Queen’s University Belfast analysed dietary data from more than 120,000 UK adults aged between 40 and 70 over six years.
They found that consuming six additional servings of flavonoid-rich foods per day, particularly berries, tea and red wine, was associated with a 28 percent lower risk of dementia.