Stanford Medicine researchers have developed a method to predict who is more likely to develop Alzheimer's disease years before memory problems appear, using resting brain activity scans. The Alzheimer's Resilience–Vulnerability Connectome (ARC) score compares an individual's brain connectivity patterns with those of SuperAgers, older adults with exceptional memory, and people with Alzheimer's.
The study, published in Science Advances , examined functional MRI scans taken while participants lay still. Researchers looked at how different brain regions' signals rose and fell together. Connections involving the front of the brain were stronger in SuperAgers, while those involving the insula were stronger in Alzheimer's patients.
Lead author Kanhao (Alex) Zhao, a postdoctoral researcher in computational neuroscience at Stanford Medicine, said the finding suggested that Alzheimer's vulnerability may be reflected in how the brain functions as an interconnected system. The ARC score summarises whether an individual's brain connectivity more closely resembles that of SuperAgers or people with Alzheimer's, with lower scores being more SuperAger-like.
When tested on a separate set of scans from 143 people who already belonged to one of those two groups, the method placed about 71 percent in the correct group. The researchers then calculated ARC scores from the first scans of 1,315 adults with no cognitive impairment and compared them with test results and clinical assessments from later years. Most datasets covered about five to six years, and the longest extended to 12 years.
People with more Alzheimer's-like scans declined faster on assessments of memory and everyday functioning over time and were more likely to develop Alzheimer's disease or mild cognitive impairment. Those with more SuperAger-like scans were younger on average. In an additional analysis of one dataset, differences in clinical ratings and test performance persisted after accounting for age at the start. Follow-up scans showed that amyloid beta, a protein that can build up into plaques in the brain, accumulated faster in people with more Alzheimer's-like scans, even though the groups started with similar levels.
Adding the ARC score improved predictions of who would develop mild cognitive impairment or Alzheimer's beyond what age, amyloid and tau levels, and genetic risk could predict. Zhao said larger prospective studies would be needed to validate the score across diverse populations and MRI scanners, and to determine whether it could improve clinical decisions.
Analysis
Why This Matters
- Could allow early identification of people at high risk for Alzheimer's before symptoms begin, enabling enrolment in prevention trials
- The ARC score appears to add predictive power beyond established biomarkers such as amyloid and tau levels and genetic risk
- If validated, the approach may help researchers test interventions earlier when they are more likely to slow or stop disease progression
Background
Alzheimer's disease is a progressive neurological disorder and the most common cause of dementia. It is characterised by the buildup of amyloid plaques and tau tangles in the brain, but these changes often begin years before memory loss becomes noticeable. SuperAgers are older adults who maintain memory performance better than typical for their age, providing a comparison to study resistance to cognitive decline. Functional MRI measures brain activity by tracking blood oxygen changes, allowing researchers to study networks of regions that activate together.
What to Watch
- Larger prospective studies following cognitively healthy individuals over several years to validate the ARC score
- Tests of the score across diverse populations and different MRI scanners to ensure reliability
- Independent research showing whether ARC-informed assessments lead to better clinical decisions or trial outcomes
Checked
12 claims in this story checked against 1 source: 12 supported.
Show each claim
- SupportedA resting brain scan may predict Alzheimer’s risk years before symptoms appear.ScienceAlert: “An early clue to that difference may lie in a brain scan, research suggests.”
- SupportedResearchers developed the ARC score to compare a person’s brain connectivity with patterns seen in SuperAgers and people with Alzheimer’s.ScienceAlert: “The team used those patterns to develop the Alzheimer's Resilience–Vulnerability Connectome, or ARC. “The ARC score summarizes whether an individual's brain connectivity more closely resembles that of SuperAgers, who maintain exceptional memory into old age, or individuals with Alzheimer's disease,” Zhao said.”
- SupportedThe study examined functional MRI scans taken while participants lay still.ScienceAlert: “The team examined scans taken while participants lay still. The technique, called functional MRI, tracks changes in blood oxygen as an indirect measure of brain activity.”
- SupportedSome connections involving the front of the brain were stronger in SuperAgers.ScienceAlert: “Some connections involving the front of the brain were stronger in SuperAgers.”
- SupportedSome connections involving the insula were stronger in people with Alzheimer’s.ScienceAlert: “Some involving the insula, a region tucked deep in the brain, were stronger in people with Alzheimer's.”
- SupportedThe separate test set included scans from 143 people who already belonged to one of the two groups.ScienceAlert: “When the researchers tested the method on a separate set of scans from 143 people who already belonged to one of those two groups”
- SupportedThe method placed about 71 percent of that test set in the correct group.ScienceAlert: “it placed about 71 percent in the correct group.”
- SupportedResearchers calculated ARC scores from first scans of 1,315 adults with no cognitive impairment.ScienceAlert: “The researchers calculated ARC scores from the first scans of 1,315 adults with no cognitive impairment”
- SupportedMost datasets covered about five to six years, and the longest extended to 12 years.ScienceAlert: “Most datasets covered about five to six years, and the longest extended to 12.”
- SupportedPeople with more Alzheimer’s-like scans declined faster on assessments of memory and everyday functioning over time.ScienceAlert: “Over time, those with more Alzheimer's-like scans declined faster on assessments of memory and everyday functioning.”
- SupportedPeople with more Alzheimer’s-like scans were more likely to develop Alzheimer’s disease or mild cognitive impairment.ScienceAlert: “They were also more likely to develop Alzheimer's disease or mild cognitive impairment”
- SupportedAdding ARC improved predictions of who would develop mild cognitive impairment or Alzheimer’s beyond predictions using age, amyloid and tau, and genetic risk.ScienceAlert: “Adding ARC improved predictions of who would develop mild cognitive impairment or Alzheimer's beyond what researchers could predict using age, scans measuring amyloid beta and tau, and genetic risk linked to the APOE gene.”
