Updates in Diagnosing Alzheimer’s Disease
Kelly O’Shea Carney, PhD, ABPP
Board Certified Geropsychologist
President, Dementia Friendly Lehigh Valley Steering Committee
As the evidence grows that reducing risk factors for dementia by adopting healthy lifestyle choices can prevent and/or delay the onset of dementia, researchers are also advancing the tools and processes for diagnosing Alzheimer’s disease early in its development. The goal of this early diagnosis is to provide more opportunity for early treatment and intervention, as well as to motivate the adoption of healthy lifestyle factors to slow progression and maintain function.
By way of example, consider how we now identify and treat heart disease. By middle age, your doctor likely orders blood tests to identify cholesterol levels and blood sugar, while also taking your blood pressure and perhaps even offering an occasional EKG to monitor heart function. All of these tests are used to look for the very earliest signs of heart disease, and if there is evidence that any of indicators are outside normal limits, your doctor will likely recommend changes in diet and exercise, perhaps send you to a specialist for further evaluation and/or recommend a medication that reduces risk for heart disease.
Until recently, the same options for identifying very early signs of Alzheimer’s disease and related disorders (ADRD) were not available. As a result, most people have not typically received a diagnosis of dementia until symptoms were clearly evident and the disease was in the middle stages of progression. However, researchers have been working tirelessly to develop the kinds of tests that will help to identify the earliest signs of Alzheimer’s and now there are blood tests, neuroimaging, and other tests that can identify increased levels of the building blocks for this disease. These tests identify increased levels of amyloid and tau in blood streams, cerebral spinal fluid, and brain metabolism. In addition, there are neuroimaging tests that can reveal early changes in brain structure and function that typically accompany the development of cognitive decline. The signs of these early changes identified by the various tests a doctor can order are called “biomarkers,” and just as we identify an increased risk for heart disease using the biomarker of cholesterol, doctors can now look for biomarkers of Alzheimer’s disease by using these new diagnostic tools.
Some of the biomarker tests are used exclusively in research settings, but a few have been approved for use in clinical settings. As the use of biomarker tests for Alzheimer’s becomes more common, perhaps too the stigma and fear of dementia will diminish. Just as the identification of high cholesterol is now used as an early warning sign to encourage a patient to alter their lifestyle and pay attention to their heart health, so too identify the biomarkers for Alzheimer’s has the potential to serve as a motivation to adopt the healthy lifestyle changes that diminish risk for dementia.
The guidelines and metrics for using the new tests to identify biomarkers for Alzheimer’s disease are still being developed and both doctors and their patients are wrestling with the risks and benefits of early diagnosis of Alzheimer’s. It is clear that the sooner the building blocks of dementia are identified in a patient, the more intentional the physician and patient can be about early interventions that may prevent, postpone, and/or slow the progression of the disease process. Researchers are still working to create new therapies and determine how effective and long-lasting diminishing risk factors might be in altering the course of disease.
For the moment, however, these advances in research and clinical care provide us all with a few hopeful developments. First, there is increasing evidence that up to 50% of all dementia cases can be delayed and/or prevented by adopting the lifestyle choices that address the identified risk factors for dementia (see the DFLV April 2024 newsletter for a review of those risk factors). Second, we know that early intervention is far more effective at bending the curve on disease progression than later intervention. Therefore, the ability to identify the biomarkers for Alzheimer’s before symptoms develop is a move in the right direction. Finally, if the use of biomarkers to identify Alzheimer’s proves to be as effective as the identification of biomarkers for heart disease in promoting healthy behavior and altering the trajectory of disease, we may all enjoy a future in which dementia is far less common than it is today.
Resources:
Livingston, Gill et al. (2024). Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission, The Lancet, Volume 404, Issue 10452, 572 – 628. https://doi.org/10.1016/S0140-6736(24)01296-0
Jack, C. R., Andrews, S. J., Beach, T. G., Buracchio, T., Dunn, B., Graf, A., Hansson, O., Ho, C., Jagust, W., McDade, E., Molinuevo, J. L., Okonkwo, O. C., Pani, L., Rafii, M. S., Scheltens, P., Siemers, E., Snyder, H. M., Sperling, R., Teunissen, C. E. & Carrillo, M. C. (2024). Revised criteria for the diagnosis and staging of Alzheimer’s disease. Nature Medicine, 30(8), 2121–2124. https://doi.org/10.1038/s41591-024-02988-7