Theoretical impact of the AT(N) framework on dementia using a community autopsy sample

Abstract

The AT(N) research framework categorizes eight biomarker profiles using amyloid (A), tauopathy (T), and neurodegeneration (N), regardless of dementia status. We evaluated associations with dementia risk in a community‐based cohort by approximating AT(N) profiles using autopsy‐based neuropathology correlates, and considered cost implications for clinical trials for secondary prevention of dementia based on AT(N) profiles. We used Consortium to Establish a Registry for Alzheimer's Disease (moderate/frequent) to approximate A+, Braak stage (IV‐VI) for T+, and temporal pole lateral ventricular dilation for (N)+. Outcomes included dementia prevalence at death and incidence in the last 5 years of life. A+T+(N)+ was the most common profile (31%). Dementia prevalence ranged from 14% (A–T–[N]–) to 79% (A+T+[N]+). Between 8% (A+T–[N]–) and 68% (A+T+[N]–) of decedents developed incident dementia in the last 5 years of life. Clinical trials would incur substantial expense to characterize AT(N). Many people with biomarker‐defined preclinical Alzheimer's disease will never develop clinical dementia during life, highlighting resilience to clinical expression of AD neuropathologic changes and the need for improved tools for prediction beyond current AT(N) biomarkers.

Association of Presynaptic Loss with Alzheimer's Disease and Cognitive Decline

“…4,5 According to the biological definition of AD 6 and recent reports, [7][8][9][10] Aβ (A) pathology presents initially in disease onset, followed by tau (T) aggregation, which subsequently results in neurodegeneration (N) and cognitive decline. However, several recent studies [11][12][13] also identified different A/T/N profiles with overlapping features of neurodegeneration and cognitive decline, indicating we may need extra techniques beyond A/T/N biomarkers to understand the progression of the disease fully. 14 Synaptic impairment appears closely linked to neurodegeneration and cognitive decline in AD.…”