Work

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

Year: 2026

Type: article

Abstract: 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.

Source: Alzheimer s & Dementia

DOI: 10.1002/alz.71976