Scientists have created new ways to test for Alzheimer's disease, focusing on memory problems rather than just detecting sticky brain deposits.
Going Beyond Traditional Tests
When doctors think someone might have Alzheimer's, they can order a blood test to check for sticky clumps called amyloid plaques in the brain. These plaques are a well-known sign of the disease.
But here's the problem: some people have many of these plaques but don't show memory loss or thinking problems. That means the current tests don't tell the whole story.
New Blood Test Shows Real Brain Effects
Dr. Randall Bateman from Washington University in St. Louis has developed a new blood test to show if Alzheimer's affects a person's thinking and memory.
His team found a specific part of a protein called tau that seems to damage brain cells and cause memory loss. This protein forms tangles inside the brain cells of people with Alzheimer's.
The researchers created a test that measures a marker called MTBR-tau243. Unlike tests for amyloid plaques, this marker is closely linked to memory loss and symptom onset.
At first, they needed spinal fluid for the test, but now they can use a simple blood sample. The test only shows high levels when people have symptoms, making it more useful than current tests.
Spinal Fluid Test Predicts Future Problems
Another team led by Dr. Tony Wyss-Coray at Stanford University created a test using spinal fluid that can predict if brain changes from Alzheimer's will affect thinking and memory.
They studied over 7,000 proteins in the spinal fluid of more than 3,000 people, using advanced analytical techniques to identify the two proteins that stood out as important markers.
When memory problems appear, one protein increases dramatically while the other decreases sharply. The ratio between these two proteins can reliably indicate whether someone's memory functions properly.
This test can even predict memory loss 10 to 20 years before someone is diagnosed with Alzheimer's, detecting the earliest subtle changes in brain function.
Why These Tests Matter
The spinal fluid test proteins involve connections between brain cells called synapses. These connections are crucial for memory and thinking.
Dr. Paul Worley from Johns Hopkins University explains that these processes happen long before obvious Alzheimer's symptoms appear. This early warning could allow doctors to start treatment much earlier.
Worley's research shows that people can remain mentally sharp despite having amyloid plaques if their brains maintain normal levels of one of these key proteins.
Better Treatment Decisions
These new tests will help doctors identify patients who would benefit most from drugs that clear amyloid plaques from the brain. This could lead to more targeted and effective treatments for Alzheimer's disease.
With the blood test, doctors can make better treatment decisions. They can determine if the plaques are causing memory problems and if the disease has progressed too far for certain treatments to help.
The research also suggests that keeping synapses healthy might be another way to treat or prevent Alzheimer's disease.
Both tests were developed with funding from the National Institutes of Health and are described in the scientific journal Nature Medicine.
