Over the last two years, we've seen some of the most impactful scientific advancements in Alzheimer's disease diagnostics and treatment compared to recent decades. With more accessible means of confirming Alzheimer's disease pathology and the availability of amyloid-targeting therapies, we're finally equipped to target the underlying pathology and help slow the cognitive and functional decline caused by this disease.
Amyloid-targeting therapies are currently FDA-approved for early symptomatic Alzheimer's disease, and it is important to note that according to recent studies, the earlier treatment is initiated the more patients can potentially benefit. This means it is critical that patients are diagnosed when symptoms first emerge, so they can receive the full benefits of these medicines if they are eligible. This requires an evolution of existing diagnostic practices in Alzheimer's disease.
Timely and accurate diagnosis has been challenging
Methods used to detect Alzheimer's disease pathology typically include amyloid positron emission tomography (PET) scans or cerebrospinal fluid (CSF) testing, both of which can be inaccessible and invasive for patients and can often lead to a delay in diagnosis.
A primary factor contributing to this delay is the long wait times commonly experienced when trying to see a specialist with experience ordering and interpreting advanced testing like an amyloid PET scan or CSF test. This stems from a prominent shortage of neurologists coupled with a growing aging population; in fact, 55% of primary care physicians caring for people living with Alzheimer's disease report there are not enough neurologists in their communities.
Further, patients often confuse signs of cognitive impairment with signs of normal aging and don't know when to request an evaluation, while nearly 98% of primary care physicians do not assess patients for cognitive impairment unless asked by a patient or loved one, exacerbating delay in diagnosis.In order for appropriate patients to receive treatment for early symptomatic Alzheimer's disease, it is imperative that a timely and accurate diagnosis is prioritized - opening the door for newer diagnostic tools that can help address these challenges.
Innovation in diagnostic measures
One possible answer is the work that's been done in development of blood-based biomarker tests that can identify or rule out circulating biomarkers in patients' blood which correlate with pathologic proteins in the brain including tau and amyloid, and aid in the evaluation and the diagnosis of early symptomatic Alzheimer's disease. Amyloid is a protein that can form abnormal clumps of protein fragments, otherwise known as amyloid plaques, that accumulate between neurons.Tau is a protein that can build up twisted fibers, otherwise known as tau tangles, that accumulate inside neurons.
Some of these blood-based biomarker tests have demonstrated they can confirm or rule out the presence of amyloid plaques in the brain with a simple blood draw. The results are correlated to the presence of amyloid, in some cases with accuracy of 90% or above. Note that additional confirmatory testing is required.
For the patients that meet the testing criteria, these tests can be paired with other cognitive assessments and clinical findings to allow for an accurate and timelier diagnosis of the disease. High quality blood biomarker tests are becoming more widely available through major reference laboratories.
Advancements are also being made in accessibility for longstanding diagnostic methods like amyloid PET scans. In 2023, the Centers for Medicare and Medicaid Services (CMS) advanced coverage for beta-amyloid PET imaging by removing coverage with evidence development (CED), allowing Medicare to cover amyloid PET scans outside of a research protocol.
Change begins with healthcare professionals
While these advancements in diagnostics are promising, the need remains for healthcare professionals (HCP) to help encourage patients to speak up and take a proactive approach to addressing cognitive impairment. It starts with HCPs taking the lead on proactive conversations with patients and their loved ones about the early signs and symptoms of Alzheimer's disease.
Additionally, it's important that cognitive exams be performed on patients aged 65 and older as part of the Medicare annual wellness exam to establish a cognitive baseline or assess for cognitive impairment if symptoms are reported or observed. If cognitive symptoms are present, HCPs may consider further evaluation for appropriate patients with additional testing such as a blood-based biomarker test or referral to a more specialized provider.
Photo: Andreus, Getty Images
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