Understanding Diagnostic Findings Helps Guide Daily Alzheimer's Care

First described by the German physician Alois Alzheimer in 1906, Alzheimer’s disease (AD) is a commonly diagnosed dementia that plagues the elderly. Characterized by memory loss and personality changes, AD (which is currently incurable) ultimately leads to death. Although the exact cause of AD is unknown, risk factors include age and family history. Over the years, the diagnosis as well as therapies available for AD and AD-related dementias (ADRD) have evolved. Genetic testing, biomarker identification and other precision diagnostics performed in individuals with cognitive symptoms can guide toward effective therapies. Joseph C. Masdeu, MD, PhD, Graham Family Distinguished Chair for Neurological Sciences, Director, Nantz National Alzheimer Center and Professor of Neurology evaluated research participants’ perspectives on AD precision diagnostics using surveys and questionnaires in a pilot study. The study, published in the Journal of Alzheimer’s Disease in 2024, concluded that participants had a high interest in genetic testing and a high degree of understanding of their positron emission tomography (PET) results. Study participants included individuals older than 50 undergoing clinical evaluation and amyloid PET imaging at the Nantz National Alzheimer Center at Houston Methodist Hospital between 2020 and 2021. Out of 88 participants who completed surveys, 39% had mild cognitive impairment due to AD, 28% suffered from AD and 22% were not cognitively impaired.

Disclosing AD test results can be a delicate issue. Hence, it is essential to understand the patient response and how this process can be improved. Masdeu added, “In this study, we are reporting the perception of the patient and their family when test results are disclosed. Most often, the impact is more important for the family since in many cases, the patient is not very aware of being sick. However, the overall response was very positive.” From the perspective of sociodemographic characteristics, the study population did not represent all neurology clinic patients since the study participants were mostly highly educated, white or european American with higher income. Moreover, surveys conducted as a part of this study only used a singular time point of six weeks after the return of PET test results which cannot evaluate if the psychological responses change with time. Further research with multiple time points in a larger sample size representative of the entire AD/ADRD patient population would shed light on the best practices to communicate biomarker test results and how to enhance supportive care. “Better understanding of whether and to what extent objective understanding of results and access to resources affect self-efficacy to understand and act upon AD/ADRD risk information is needed. Our findings can inform future clinical implementation of AD/ADRD through improved understanding of participants’ experience with return of results and interest in genetic testing,” Masdeu noted. According to the Centers for Disease Control and Prevention (CDC), 5.8 million Americans were living with AD in 2020, and this number is projected to reach 14 million by 2060. Also, AD is one of the top 10 leading causes of death in the U.S. and fifth among the elderly over 65. The annual costs of treating AD in the nation ranged from $159 billion to $215 billion in 2020—by 2040, treating AD is projected to be between $379 billion and $500 billion. Amyloid plaques and neurofibrillary tangles characterize AD brain pathology, although how they contribute to AD remains unclear. Amyloid plaques accumulate in the brain long before dementia symptoms appear. PET imaging helps identify excess amyloid β plaques in the brain. Currently, disease-modifying therapies are available that reduce amyloid-β deposition. These include antibodies that can clear or reduce brain amyloid plaques. In light of these developments, PET imaging in individuals with early AD has become clinically relevant. For individuals with a family history of AD, there are three methodologies to evaluate AD risk: blood test to determine levels of amyloid β and tau—this method is not the most reliable; lumbar puncture to evaluate amyloid β and tau amounts in the cerebrospinal fluid and PET scans, which is the most reliable method. Presently, medications are available to remove amyloid β plaques from the brain. However, this process is likely to be most effective before AD symptoms appear. Once the patient shows symptoms, the deposition of the protein tau begins, and at that point, the process of AD development is more resistant to modification by removal of amyloid β plaques.