The AT(N) Framework is an Alzheimer's disease classification scheme that groups fluid and brain imaging biomarkers based around the underlying disease processes they detect. For example, brain scans and cerebrospinal fluid measurements of amyloid are grouped under 'A', while biomarkers that measure tau are grouped under 'T'. Together, AT(N) profiles are designed to help clinicians and researchers better understand and categorise the disease processes that may lead to dementia.
To check the accuracy and diagnostic capability of AT(N) profiles, a group of researchers led by Prof. Paul Crane (University of Washington, Seattle, US) calculated the AT(N) profiles for a large community-based cohort of individuals, basing their calculations on autopsy correlates of AT(N). In their study, published recently in Alzheimer's and Dementia, Prof. Crane and colleagues found that of 603 individuals with complete AT(N) profiles and known dementia status, over 30% were biomarker-positive for amyloid, tau and neurodegeneration (A+T+(N)+). However, almost a third of individuals with this high-risk biomarker status remained dementia-free before death. This suggests that a substantial proportion of older individuals may be resilient to cognitive decline, despite having high levels of amyloid, tau and neurodegeneration.