A new test could detect Alzheimer’s disease at least ten years before symptoms appear – paving the way for early treatment.
The discovery of a fall in levels of a certain type of genetic material could signal an increased risk of developing Alzheimer’s.
The biological marker is found in cerebral spinal fluid (CSF) at least 10 years before signs of dementia become apparent.
Currently, the only way to accurately diagnose the disease is by post-mortem neuropathological analysis, although memory and other brain function tests are used to determine whether drugs and other treatment may help.
Spanish researchers at the CSIC Institute of Biomedical Research of Barcelona believe they may have found a marker that could suggest the disease process is underway before symptoms start to show.
A new test could detect Alzheimer’s disease at least ten years before symptoms appear
They found a drop in the content of mitochondrial DNA (mtDNA) – genetic material present in the energy centre of cells – in spinal fluid may be a signal for the disease.
They suggest that decreased mtDNA levels reflect the diminishing ability of mitochondria to power brain cells, thus triggering their death.
The drop in the concentration of mtDNA precedes the appearance of other recognized biochemical Alzheimer’s biomarkers, suggesting the process of Alzheimer’s disease starts earlier than previously thought and that mtDNA depletion may be one of the earliest predictors.
Researchers have previously been unable to detect the genetic material in spinal fluid, but they used a new technique to amplify tiny amounts, says a study in the journal Annals of Neurology.
The researchers hope other labs and hospitals will be able to replicate the results.
The researchers say by finding a way to block the degeneration, clinicians may be able to diagnose and treat the disease before symptoms even appear.
Lead author Dr. Ramon Trullas said: “If our initial findings can be replicated by other laboratories, the results will change the way we currently think about the causes of Alzheimer’s.”
“This discovery may enable us to search for more effective treatments that can be administered during the pre-clinical stage.”
A new study suggests that keeping mentally active by reading books or writing letters helps protect the brain in old age.
A lifetime of mental challenges leads to slower cognitive decline after factoring out dementia’s impact on the brain, US researchers say.
The study, published in Neurology, adds weight to the idea that dementia onset can be delayed by lifestyle factors.
An Alzheimer’s charity said the best way to lower dementia risk was to eat a balanced diet, exercise and stay slim.
In a US study, 294 people over the age of 55 were given tests that measured memory and thinking, every year for about six years until their deaths.
Keeping mentally active by reading books or writing letters helps protect the brain in old age
They also answered a questionnaire about whether they read books, wrote letters and took part in other activities linked to mental stimulation during childhood, adolescence, middle age, and in later life.
After death, their brains were examined for evidence of the physical signs of dementia, such as brain lesions and plaques.
The study found that after factoring out the impact of those signs, those who had a record of keeping the brain busy had a rate of cognitive decline estimated at 15% slower than those who did not.
Dr. Robert Wilson, of Rush University Medical Center in Chicago, who led the study, said the research suggested exercising the brain across a lifetime was important for brain health in old age.
He said: “The brain that we have in old age depends in part on what we habitually ask it to do in life.
“What you do during your lifetime has a great impact on the likelihood these age-related diseases are going to be expressed.”
A new study has revealed that some of the earliest signs of Alzheimer’s disease have been found in the brain, more than two decades before the first symptoms usually appear.
Treating the disease early is thought to be vital in order to prevent damage to memory and thinking.
A study, published in the Lancet Neurology, found differences in the brains of people destined to develop an early form of Alzheimer’s.
Experts said the US study may give doctors more time to treat people.
Alzheimer’s disease starts long before anyone would notice; previous studies have shown an effect on the brain 10-15 years before symptoms.
It is only after enough brain cells have died that the signs of dementia begin to appear – some regions of the brain will have lost up to 20% of their brain cells before the disease becomes noticeable.
However, doctors fear so much of the brain will have degenerated by this time that it will be too late to treat patients. The failure of recent trials to prevent further cognitive decline in patients with mild to moderate Alzheimer’s disease has been partly put down to timing.
A team at the Banner Alzheimer’s Institute in Arizona looked at a group of patients who have familial Alzheimer’s. A genetic mutation means they nearly always get the disease in their 40s. Alzheimer’s normally becomes apparent after the age of 75.
Brain scans of 20 people with the mutation, aged between 18 and 26, already showed differences compared with those from 24 people who were not destined to develop early Alzheimer’s.
The fluid which bathes the brain and spinal cord also had higher levels of a protein called beta-amyloid.
The researchers said differences could be detected “more than two decades before” symptoms would appear in these high-risk patients.
Dr. Eric Reiman, one of the scientists involved, said: “These findings suggest that brain changes begin many years before the clinical onset of Alzheimer’s disease.
“They raise new questions about the earliest brain changes involved in the predisposition to Alzheimer’s and the extent to which they could be targeted by future prevention therapies.”
Prof. Nick Fox, from the Institute of Neurology at University College London, said some of his patients had lost a fifth of some parts of their brain by the time they arrived at the clinic.
He said: “I don’t think this pushes us forwards in terms of early diagnosis, we already have markers of the disease.
“The key thing this does is open up the window of early intervention before people take a clinical and cognitive hit.”
However, he said this raised the question of how early people would need to be treated – if drugs could be found.
Dementia signs
• Struggling to remember recent events
• Problems following conversations
• Forgetting the names of friends or objects
• Repeating yourself
• Problems with thinking or reasoning
• Confusion in familiar places
