Brain Scans Reveal How Age Shapes Alzheimer's in Younger Patients

By comparing PET scans between younger and older patients with Alzheimer's disease, researchers have uncovered key differences in the condition's biology between these age groups. Their analysis, involving imaging data from 601 participants, showed that patients with early-onset disease display more severe accumulation of toxic tau protein – providing critical data to guide future trial designs and treatment strategies. Although Alzheimer's disease usually appears after the age of 65, a minority of patients develop it earlier in life. Patients with early-onset cases tend to show different symptoms, and studies suggest that they also exhibit distinct patterns in the buildup of disease-linked proteins such as tau and amyloid-beta. These differences could have implications for future research into diagnostics, biomarkers, and treatment response, so Konstantinos Chiotis and colleagues set out to interrogate them in detail. They examined tau PET scans in a cohort of 390 individuals with early-onset Alzheimer's disease (under 65 years of age) and a cohort of 211 people with late-onset disease (over 65 years of age). Compared with the older patients, the younger ones had a higher burden of tau protein at the onset of disease, and their levels of the protein increased more rapidly over time across a wider area of the brain. The early-onset group also displayed a stronger correlation in their scans between tau buildup, the accumulation of amyloid-beta protein, and broader cognitive decline. "Developing a deeper understanding of the similarities and differences in AD pathophysiology across the age spectrum will advance our ability to identify optimal therapeutic approaches," Chiotis et al. write.