Alzheimer's & Dementia · Nov 4, 2026

Measurement precision matters: Accounting for uncertainty alters estimated memory trajectories across the cognitive spectrum

By Trittschuh EH, Scollard P, Crane PK et al.

INTRODUCTION: Harmonized cognitive composites are widely used to study longitudinal cognitive decline. Although harmonization places scores on a common latent scale, measurement precision varies across visits, age, and diagnosis, but is typically ignored in longitudinal models. METHODS: We analyzed harmonized memory scores and time‐varying standard errors from the National Alzheimer's Coordinating Center Uniform Data Set. We compared a naïve mixed‐effects model that did not incorporate measurement uncertainty with two precision‐aware models: a frequentist precision‐weighted and a Bayesian measurement‐error model. Comparisons were based on estimated age of memory impairment. RESULTS: Accounting for measurement precision produced age‐dependent differences in estimated memory trajectories. Naïve models predicted higher memory scores at older ages in cognitively normal and mildly impaired participants but lower scores in Alzheimer's dementia (AD). Precision‐aware models estimated threshold crossing 1.5–3 years earlier than the naïve model. DISCUSSION: Incorporating visit‐specific measurement precision alters estimated cognitive trajectories and the timing of clinically interpretable memory impairment.

doi.org/10.1002/alz.71976Open accessPubMed 42982742Populations