A blood test can detect signs of Alzheimer’s years before symptoms appear.
Most patients are not diagnosed with Alzheimer’s until they develop memory problems, but an early sign of the disease comes from clumps of a protein called beta amyloid that build up in the brain.
A blood test that detects these toxic clumps was able to identify all but one of 147 people with Alzheimer’s disease in a new study.
The test also identified people who would develop cognitive impairment up to ten years before diagnosis.
News of the new blood test comes on the heels of a separate study that suggested Alzheimer’s could be diagnosed simply by a urine test in the future.
The blood test called SOBA could detect the presence of the neurological plaques that are precursors to Alzheimer’s disease up to 10 years before the patient received a formal diagnosis
The blood test, the so-called soluble oligomer binding test (SOBA), needs to be tried in many more people and is still in its early stages.
But Valerie Daggett, a professor of bioengineering at the University of Washington who developed the test, said: ‘What clinicians and researchers wanted is a reliable diagnostic test for Alzheimer’s disease.
“And not just a test that confirms a diagnosis of Alzheimer’s, but one that can detect signs of the disease before cognitive impairment occurs. What we show here is that SOBA can be the basis of such a test.
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The new test targets amyloid beta – the proteins that are a red flag for Alzheimer’s disease.
When people get Alzheimer’s, beta-amyloid proteins in the brain fold incorrectly, creating “alpha sheets” that stick together in clumps.
The test uses synthetic alpha sheets to extract the beta-amyloid from a person’s blood and show how much is in their body.
This can mark people with abnormally high levels, who are more likely to have Alzheimer’s disease, mild cognitive impairment, which can lead to Alzheimer’s disease, or cognitive impairment not related to Alzheimer’s disease.
Researchers tested 158 blood samples from people with these three health conditions and 221 from people with no diagnosed memory problems.
The test was 99 percent accurate in correctly identifying each sample’s diagnosis.
The test, tested on 379 samples from a total of 310 people, initially seemed flawed in giving a positive result for 11 apparently healthy people.
But 10 of these people, for whom follow-up data were available, were later diagnosed with cognitive impairment and Alzheimer’s disease.
In one case of an older person with mild cognitive impairment, the test was positive 10 years before diagnosis.
The research paper on the test, published in the journal Proceedings of the National Academy of Sciences, also gives examples of a 74-year-old woman who tested positive for more than five years before being diagnosed with Alzheimer’s disease after her death.
An 82-year-old man had a positive test result four years before being diagnosed with mild cognitive impairment.
Blood tests are the main hope for one day screening people for early signs of dementia, as is currently being done for early cancer.
CT and PET scans of the brain are expensive and expose people to radiation, while epidural tests to look for clues in the spinal fluid are uncomfortable and invasive.
While urine and blood tests are faster and easier, more research is needed on how well they work.
In the study, the team also showed that SOBA can be easily modified to detect toxic clumps of another type of protein associated with Parkinson’s disease.
‘We are discovering that many human diseases are related to the build-up of toxic oligomers that make up these alpha sheet structures,’ said Dr Daggett.
‘Not only Alzheimer’s, but also Parkinson’s, type 2 diabetes and more. SOBA picks up on that unique alpha sheet structure, so we hope this method can help diagnose and study many other ‘protein misfolding’ diseases.’
WHAT IS DEMENTIA? THE KILLER DISEASE THAT DEPRIVES SUFFERERS OF THEIR MEMORIES
Dementia is an umbrella term used to describe a range of neurological conditions
A WORLDWIDE CARE
Dementia is an umbrella term used to describe a range of progressive neurological conditions (affecting the brain) that affect memory, thinking, and behavior.
There are many different forms of dementia, with Alzheimer’s disease being the most common.
Some people have a combination of dementias.
Regardless of which type is diagnosed, each person experiences his or her dementia in their own unique way.
Dementia is a global problem, but it is most common in wealthier countries, where people are likely to live very old.
HOW MANY PEOPLE ARE AFFECTED?
The Alzheimer’s Society reports that there are more than 900,000 people living with dementia in the UK today. This is expected to rise to 1.6 million by 2040.
Alzheimer’s disease is the most common form of dementia, affecting between 50 and 75 percent of those diagnosed.
There are an estimated 5.5 million Alzheimer’s patients in the US. A similar percentage increase is expected for the coming years.
As a person’s age increases, so does the risk of developing dementia.
The rate of diagnoses is improving, but many people with dementia are thought to remain undiagnosed.
IS THERE A MEDICINE?
Currently there is no cure for dementia.
But new drugs can slow its progression, and the sooner it’s caught, the more effective the treatments are.
Source: Alzheimer’s Association