The Alzheimer’s Association has created a new biology-based criteria for the diagnosis and staging of Alzheimer’s disease (AD). These criteria, last revised in 2018, now include cognitive performance and functionality as well as new blood and CSF (spinal fluid) biomarkers. It has long been known that the neuropathological changes occur long before clinical suggestion of disease.
The Alzheimer’s Disease biomarkers were divided into 3 categories:
1. Biomarkers specific to AD which if abnormal are sufficient to make the diagnosis
2. Nonspecific biomarkers that are clinically important in AD but also are involved in other diseases of the brain
3. Biomarkers of other diseases that often occur with AD but do not cause it.
The biomarker specific to AD (category 1) are divided into Core 1 and Core 2.
Core 1: Biomarkers which can be detected early on prior to clinical symptoms and directly measure either amyloid plaques or phosphorylated tau (p-tau). These include PET scans with specific contrasts (amyloid PET);
CSF markers (amyloid beta 42/40 ratio, CSF p-tau181/amyloid beta 42 ratio, and CSF total (t)-tau/amyloid beta 42 ratio); and blood biomarkers, such as p-tau217.
Core 2: Biomarkers which emerge as AD becomes clinically evident. These
include PET scans with different contrasts (looking for tau) and fragments of
tau in body fluids.
The combination of Core 1 and Core 2 biomarkers help with staging the disease once the diagnosis has been made. The choice between biomarkers (imaging vs. CSF examination vs. blood tests) will in part be made by access and insurance coverage. The presence of more than one helpful option will go far to advance accessibility across geographic and socioeconomic groups. Of note, the current intended use of AD biomarkers is for the evaluation of symptomatic patients only as there are no approved disease-targeted therapies for patients without cognitive impairment-YET. BeCareLink can be instrumental in detecting cognitive impairment before it becomes evident to the patient or the physician. Early detection will most certainly result in better clinical outcomes now that treatment options are coming to the market.
The BeCare Neuro app has cognitive activities that are based on formal neuropsychological tests. Download the app at: https://play.google.com/store/apps/developer?id=BeCare+Link+LLC&hl=en_US&gl=US or https://apps.apple.com/ca/developer/becare-link/id1327398652
The 2024 revised criteria for diagnosis and staging of AD can be found at
https://doi.org/10.1002/alz.13859.