Differences in the way brain regions communicate may help identify who is at risk of Alzheimer’s years before memory problems begin, according to research published in Science Advances.
Researchers at Stanford Medicine analyzed resting-state brain scans to investigate why some older adults develop problems with memory and thinking while others retain strong cognitive abilities.
They first compared two groups: people diagnosed with Alzheimer’s and “super agers,” older adults whose memory is similar to that of people decades younger. Rather than focusing on physical changes such as amyloid plaques or brain shrinkage, the team examined patterns of communication between brain regions.
From those patterns, the researchers created a measure called the Alzheimer’s resilience-vulnerability connectome score, or ARC score. It distinguished super agers from people with Alzheimer’s with about 85% accuracy.
The team then tested the model on more than 1,300 adults aged 55 to 70 who showed no cognitive impairment. Although everyone performed normally on memory tests, their brain scans varied: some resembled the super-ager pattern, while others were closer to patterns associated with Alzheimer’s.
During follow-up lasting as long as 12 years—most participants were tracked for five to six years—those with more Alzheimer’s-like brain activity experienced faster declines in memory and thinking. They also developed more amyloid plaques and were more likely to receive an Alzheimer’s diagnosis.
The ARC score performed as well as, or better than, established measures such as amyloid and tau biomarkers and genetic testing when identifying early decline, the researchers reported. Combining the score with existing biomarkers improved its predictive performance further.
Alzheimer’s affects millions of older adults worldwide. One challenge in treating the disease is that brain damage can begin years before symptoms become noticeable, when available treatments may offer limited benefit.
The researchers cautioned that the scan-based approach is not ready to be used on its own to diagnose Alzheimer’s. Further studies will be needed to verify its accuracy and compare it with other emerging tests.
Still, learning how brain activity differs between healthy aging and neurodegeneration could help guide research into future treatments, including noninvasive methods that stimulate the brain. The team said it will be important to determine both which brain areas to target and what activity patterns treatment should aim to change.
