TUESDAY, May 5, 2026 (HealthDay News) -- Three trajectories of preclinical progression have been identified in Alzheimer disease, according to a study published online April 21 in Alzheimer's & Dementia.Runpeng Li, Ph.D., from the University of Southern California in San Diego, and colleagues used data from the Anti-Amyloid Treatment in Asymptomatic Alzheimer's Disease Study and the Longitudinal Evaluation of Amyloid Risk and Neurodegeneration Study, which enrolled amyloid beta (Aβ)-positive and Aβ-negative individuals, to identify subgroups of cognitive decline and predictors of heterogeneity in preclinical progression.The researchers identified three trajectory classes: stable, slow decliners, and fast decliners. There was an association for higher phosphorylated tau at 217, smaller hippocampal volume, and elevated tau positron emission tomography with declining classes. Of the Aβ-positive individuals, about 70 percent were stable."These results suggest we may need to rethink how we design clinical trials in preclinical Alzheimer's disease," Li said in a statement. "Many people with Alzheimer's remain stable over the course of a study, which can make it hard to tell if a treatment is working. Identifying those who are more likely to decline could make trials more efficient and more informative."Several authors disclosed ties to the biopharmaceutical industry; the study was partially funded by Avid Radiopharmaceuticals and Eli Lilly and Company.Abstract/Full Text (subscription or payment may be required).Sign up for our weekly HealthDay newsletter