Advances in Early Alzheimer’s Detection

The prevalence of Alzheimer’s disease (AD) is rapidly increasing as individual life spans across the world increase.  It is currently the most common form of dementia, marked by the overproduction and aggregation of amyloid β (Aβ) and tau proteins in the brain. These aggregates may trigger various symptoms in the brain, including inflammation, that lead to progressive declines in cognition, memory, and social functionality in patients. Currently, there is no cure and the available treatments only manage some of the symptoms of the disease.

Unfortunately, the newest findings are still far from curing or preventing AD, but there have been some major advances in earlier detection of the disease. Catching Alzheimer’s early can maximize a patient’s treatment options and enable them to better prepare for their future in terms of care. Below are some of the most recent advances in early detection of AD.

Regular Eye Exams – A recent study has shown the importance of keeping up with regular eye exams as we age. The researchers in this study examined brain scans and retinal samples from both mouse and human AD patients and found the presence of Aβ and tau proteins in the retina as well as increased inflammation there and throughout the brain¹. The difference in retinal thickness is significant enough due to the inflammation to detect during direct and non-invasive imaging as part of a normal health check-up. This can be a reliable detection of the early presence Aβ and tau biomarkers, allowing large-scale screening and monitoring of at-risk populations for AD.

Aβ Imaging via PET scans – Aβ PET scanning has become a mainstay in AD diagnosis and is revolutionizing clinical research. PET, or Positron Emission Tomography, is a nuclear medicine imaging tool that can be used to make a picture of amyloid plaque accumulation within the brain. Recently, researchers have developed more sensitive radiolabeling agents that can detect smaller and smaller amounts of Aβ in the brain, supporting the case that PET scans can more accurately diagnose patients with AD². Currently PET scans are not commonly used in clinical practice due to the lack of reimbursement under current Center for Medicare and Medicaid Services guidelines in the United States, however researchers and clinicians are diligently working towards making the case for PET in AD diagnosis and studies are underway to further inform the field on the benefits of PET utilization.

Genetic testing – Genetic markers for AD predication have been a topic of intense research for early detection methodologies. Many of these markers focus on single genes, such as the APOE gene, which is known to increase the risk of developing AD 15-fold, however recent advances have taken this a step forward. New genetic testing techniques combine all the previous genetic marker research to check for mutations in 26 genes that have been found to be prevalent in a sample size of over 700,000 dementia patients³. This technique looks for the presence of these 26 genes and calculates an individual ‘hazard score’, which can be used to assist physicians in arriving at a diagnosis of AD much earlier as well as target the right type of patients for clinical research of new therapies. In addition, a patient who has received early knowledge of their elevated risk for AD can be encouraged by their physicians to improve their lifestyles to cut their chance of developing disease.

These are some of the many new findings that have led to a shift in focus in AD research from testing therapies that only address some symptoms of the disease to prediction of the onset of AD well before the debilitating symptoms begin. Hopefully, with the ability to diagnose AD earlier, the shift in focus will also lead to an emergence of preventative therapies that can slow the progressive cognitive decline that plagues so many people dealing with this disease.

References:

1. Hart NJ, Koronyo Y, Black KL, Koronyo-Hamaoui M. Ocular indicators of Alzheimer’s: exploring disease in the retina. Acta Neuropathol. 2016;132(6):767-787. PMID: 27645291.
2. Anand, K. & Sabbagh, M. Amyloid Imaging: Poised for Integration into Medical Practice Neurotherapeutics 2017;14:54. PMID: 27571940
3. Desikan RS, Fan CC, Wang Y, Schork AJ, Cabral HJ, et al. (2017) Genetic assessment of age-associated Alzheimer disease risk: Development and validation of a polygenic hazard score. PLOS Medicine 14(3): e1002258. PMID: 28350793