Researchers at the University of California San Diego have uncovered new insights into one of Alzheimer’s disease’s most puzzling questions: why some older adults remain mentally sharp despite having hallmark brain changes linked to the disease. This condition—known as asymptomatic Alzheimer’s disease (AsymAD )— has long been observed but poorly understood. Decoding this natural resilience could pave the way for earlier detection and new strategies to prevent memory loss before symptoms begin.
“Even when the brain shows clear signs of Alzheimer’s, some people stay mentally sharp,” said co-senior author Sushil K. Mahata, PhD, adjunct professor of medicine at UC San Diego School of Medicine and research physiologist at the VA San Diego Healthcare System. “We’re beginning to uncover the brain’s built-in defenses—and that could fundamentally change how we approach treatment.”
More than 7 million Americans are currently living with Alzheimer’s disease. However, an estimated 20–30% of individuals with Alzheimer’s-related brain pathology remain asymptomatic, maintaining normal cognition despite the presence of amyloid plaques and neurofibrillary tangles in the brain.
To investigate this phenomenon, UC San Diego researchers analyzed gene expression across thousands of human brain samples. Using an advanced artificial intelligence–based framework developed by co-senior author Debashis Sahoo, PhD, associate professor of pediatrics and computer science at UC San Diego, the team identified consistent molecular patterns linked to disease progression — and protection — across multiple independent datasets.
Key findings:
Together, these findings identify CgA-centered stress-response pathways as key drivers of cognitive resilience. The study also introduces a powerful combined computational and experimental framework to accelerate the discovery of preventive therapies for Alzheimer’s disease.
The study, published in Acta Neuropathologica Communications , was led by Sahoo and Mahata. The study was funded, in part, by the National Institutes of Health.
Acta Neuropathologica