A simple blood test could detect the onset of dementia 16 years before symptoms are noticed, a new study has found.
Researchers found a protein in the blood that can “very accurately” predict degenerative brain disease well before signs of memory loss and confusion begin.
They hope the blood test will see earlier diagnoses of dementia and consequentially help bring about earlier intervention for the devastating disease.
The discovery could see routine screening for degenerative brain conditions including Alzheimer’s Disease and multiple sclerosis being offered in clinics in the next years.
An international team of neurologists found the speed of a patient’s memory loss was tracked by rises in a structural protein that leaks into their blood after brain cells die.
The increases in the “neurofilament light chains” precisely matched the speed with which the precuneus – a part of the brain involved in memory – thinned and shrank.
Previous studies showed the levels of the protein structure in spinal fluid was a good predictor for dementia but this required invasive spinal tap operations.
Neurologists at the Washington University of School of Medicine and German Centre for Neurodegenerative Diseases in Germany said only a blood test is necessary after discovering the cellular remains were “surprisingly resistant” to degradation.
Their findings were based on years of brain scans of 405 people with genes that causes Alzheimer’s Disease to develop as young as their 30s, from the Dominantly Inherited Alzheimer’s Network.
Senior author Professor Mathias Jucker, at the German Centre for Neurodegenerative Diseases in Tübingen, Germany, said: “The test accurately shows the course of the disease and is therefore a powerful instrument for investigating novel Alzheimer’s therapies in clinical trials.
“We were able to predict loss of brain mass and cognitive changes that actually occurred two years later.
“The fact that there is still no effective treatment for Alzheimer’s is partly because current therapies start much too late.”
He said his team found the changes in the concentration of the protein in the blood reflected neuron damage “very accurately”.
He added: “It is not the absolute neurofilament concentration, but its temporal evolution, which is meaningful and allows predictions about the future progression of the disease.
“It will be important to confirm our findings in late-onset Alzheimer’s disease and to define the time period over which neurofilament changes have to be assessed for optimal clinical predictability.”
The researchers hope the test will be adapted as an early warning sign for Alzheimer’s Disease and other neurodegenerative disorders within years.
The protein also spills out into the blood via the spinal cord in people with Lewy body dementia and Huntington’s disease, and rises dramatically in people with multiple sclerosis during a flare-up and in football players immediately after a blow to the head.
The researchers used a blood test kit similar to others available commercially but not yet approved by the experts at the US Food and Drug Administration agency.
Study author Assistant Professor Brian Gordon at Washington University’s Mallinckrodt Institute of Radiology, in St. Louis, US, said: “This is something that would be easy to incorporate into a screening test in a neurology clinic.
“We validated it in people with Alzheimer’s disease because we know their brains undergo lots of neurodegeneration, but this marker isn’t specific for Alzheimer’s.
“High levels could be a sign of many different neurological diseases and injuries.”
His team is now working to determine how much protein in the blood is too much, and how quickly protein levels can rise before it becomes a cause for concern, to create the clinical test.
Prof Gordon said: “I could see this being used in the clinic in a few years to identify signs of brain damage in individual patients.
“We’re not at the point we can tell people, ‘In five years you’ll have dementia.’ We are all working towards that.”
Co-author Stephanie Schultz, a Washington University graduate, added: “Sixteen years before symptoms arise is really quite early in the disease process, but we were able to see differences even then.
“This could be a good preclinical biomarker to identify those who will go on to develop clinical symptoms.”
The findings were published in Nature Medicine today (Mon).
By Berny Torre