Introduction: The Heterogeneity of Alzheimer’s Disease
The clinical presentation of Alzheimer’s disease (AD) is remarkably heterogeneous. While the amyloid-tau-neurodegeneration (ATN) framework has provided a biological backbone for diagnosis, clinicians frequently encounter patients whose cognitive performance does not align with their biomarker profile. Some individuals remain cognitively stable despite high pathological burdens—a phenomenon termed cognitive resilience—while others exhibit rapid decline even with relatively low levels of classic AD pathology, often due to the presence of non-AD copathologies. Understanding these discrepancies is critical in the current era of disease-modifying therapies (DMTs), where predicting a patient’s individual trajectory is essential for risk-benefit stratification.
A landmark study by Brown et al. (2025), published in JAMA Neurology, explores this ‘tau-clinical mismatch.’ By evaluating individuals who are amyloid-positive (Aβ+), the researchers sought to determine whether the discordance between tau burden (measured via PET or plasma p-tau217) and clinical symptoms (measured by the Clinical Dementia Rating Sum of Boxes, CDR-SB) could serve as a proxy for identifying underlying copathologies or inherent resilience.
