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It’s one of the most feared diagnoses for older Americans: Alzheimer’s disease. Especially for those who have watched a parent or other family member suffer, the prospect of developing Alzheimer’s evokes a sense of dread. There is no cure for the disease, which afflicts nearly seven million people in the United States, including about a third of those over the age of 85.
However, there are interventions available which can slow the progress of Alzheimer’s. The earlier a patient’s care team can detect Alzheimer’s disease, the sooner these treatments can be offered, and the more effective they are likely to be.
The Current State of Alzheimer’s Testing
Unfortunately, early diagnosis is not common. For a long time, testing has been cumbersome and costly, and only available for people who were already exhibiting problems with thinking and memory. These cognitive signs and symptoms often point to Alzheimer’s, but are not enough for a definitive diagnosis. Up to one-third of patients diagnosed with Alzheimer’s based solely on cognitive symptoms are misdiagnosed.
It is obviously not a good use of resources to administer therapies for Alzheimer’s disease to patients whose symptoms are caused by other conditions. Accordingly, further testing is usually required before treating patients for Alzheimer’s disease. The point of that testing is to confirm the presence of amyloid plaques in the brain, which are a hallmark of Alzheimer’s.
The presence of amyloid plaques can be confirmed through a variety of tests, including positron emission tomography (PET) scans of the brain and analysis of cerebrospinal fluid, which requires a spinal tap. Not only are these tests costly (and in the case of a spinal tap, painful), they are only available to those who are already showing some signs of cognitive decline.
The Significance of a Blood Test for Alzheimer’s Disease
The potential cost, pain, and inaccessibility of the existing tests, paired with the reality that Alzheimer’s is incurable at present, means that many people will put off testing as long as possible. Fear of being diagnosed with an incurable, life-changing disease may outweigh the benefit they expect from available therapies.
But amyloid plaques don’t just suddenly appear and cause symptoms. Amyloid builds up slowly in the brain over time. There may be up to two decades in which a future Alzheimer’s patient is presymptomatic, and with little or no neurodegeneration. That matters, because while the therapies currently available are helpful, they do not reverse the neuron (nerve cell) loss caused by Alzheimer’s.
If patients could be diagnosed sooner, they could be treated sooner. That might prevent the loss of brain cells even before the patient is showing signs of the disease or mild cognitive impairment (MCI), often a precursor to Alzheimer’s. (Currently, it is estimated that more than 90% of people with MCI are undiagnosed.)
A recent research study found that a new blood test for Alzheimer’s disease performs as well as existing FDA-approved spinal fluid tests. Unlike existing tests for Alzheimer’s disease, this simple, non-invasive test can be administered not only to people showing cognitive symptoms of Alzheimer’s, but those who appear healthy.
Using the Ptau-217 Blood Test to Detect Alzheimer’s Disease
The blood test was developed by researchers at Washington University in St. Louis. The study compared the ability of four tests to identify whether a patient has amyloid in their brain: the ptau-217 blood test, and three existing cerebrospinal fluid tests already approved by the FDA. A total of over 1,750 people were tested; some had cognitive symptoms classified as mild or very mild; others were apparently healthy with no signs of cognitive impairment.
The results were impressive. The ptau-217 blood test performed just as well at identifying amyloid buildup as the cerebrospinal fluid tests: the accuracy scores for all tests ranged between 95% and 97%. The researchers also measured the accuracy of the four tests in detecting the levels of tau tangles, also found in Alzhemer’s patients, in the brain. In this secondary analysis, the ptau-217 blood test actually outperformed tests using cerebrospinal fluid, with accuracy ranging from 95% to 98%.
What a Blood Test for Alzheimer’s Could Mean for the Future
The expression “time is brain” was coined to refer to the importance of prompt treatment for a stroke. But in a very real sense, it also applies to Alzheimer’s disease. At a minimum, early detection of Alzheimer’s disease can help patients take steps to prevent neuron loss and delay the onset or slow the progression of the disease.
Researchers hope for even greater developments with a blood test for Alzheimer’s disease. Researchers hope to eventually find a way to clear amyloid plaque from the brain, preventing a buildup and the resulting neurodegeneration. Conceivably, presymptomatic patients with a positive ptau-217 blood test could have a regular treatment to clear amyloid every few years, and never develop the disease at all.
Until that day, it’s wise to make efforts to reduce the risk of developing Alzheimer’s disease, and to do estate planning that plans for the possibility of future incapacity due to dementia. To learn more about planning for Alzheimer’s and taking steps to prevent it, contact Estate Planning & Elder Law Services to schedule a consultation.
