Development of the National Institute on Aging (NIA)–Alzheimer’s Association (AA) research framework system for staging was designed to stage two types of information independently from each other – disease severity using biomarkers, and the severity of cognitive impairment.3 AT(N) measures are used for definition and staging of AD.3 The presence of Ab biomarkers (A) determines if an individual is on the Alzheimer’s continuum, while the presence of both tau (T) and Ab biomarkers determines whether a patient on the Alzheimer’s continuum has AD.3 Neurodegenerative/neuronal injury biomarkers (N) and cognitive symptoms are not specific to AD are only used to stage disease severity rather than to define presence of the Alzheimer’s continuum.3
For more information on the neurobiology and aetiology of AD, see our slide deck here.
References:
1. Therriault J, Zimmer ER, Benedet AL, et al. Staging of Alzheimer’s disease: past, present, and future perspectives. Trends Mol Med 2022; 28 (9): 726–741.
2. Jack CR Jr, Knopman DS, Jagust WJ, et al. Tracking pathophysiological processes in Alzheimer’s disease: an updated hypothetical model of dynamic biomarkers. Lancet Neurol 2013; 12 (2): 207–216.
3. Jack CR Jr, Bennett DA, Blennow K, et al; Contributors. NIA-AA research framework: toward a biological definition of Alzheimer’s disease. Alzheimers Dement 2018; 14 (4): 535–562.
4. Therriault J, Pascoal TA, Lussier FZ, et al. Biomarker modeling of Alzheimer’s disease using PET-based Braak staging. Nat Aging 2022; 2 (6): 526–535.
5. Knopman DS, Amieva H, Petersen RC, et al. Alzheimer disease. Nat Rev Dis Primers 2021; 7 (1): 33.
6. Rafii MS, Sperling RA, Donohue MC, et al. The AHEAD 3-45 Study: design of a prevention trial for Alzheimer’s disease. Alzheimers Dement 2023; 19 (4): 1227–1233.
7. van Dyck CH, Swanson CJ, Aisen P, et al. Lecanemab in early Alzheimer’s disease. N Engl J Med 2023; 388 (1): 9–21.
