Stanford team's ARC scale from resting fMRI separates resilient and vulnerable brains with about 85% accuracy

Researchers at Stanford University have developed a method of assessing brain activity that estimates the risk of Alzheimer's disease before noticeable memory impairment appears, according to pravda.ru. The work was published in Science Advances. pravda.rupravda.rupravda.ruOpen source ↗

The authors say that patterns of brain activity, calculated on a scale called ARC, predict cognitive decline earlier and more accurately than the traditionally used biomarkers, amyloid plaques and tau proteins, which usually show up only at late stages of the disease.

How the ARC scale was built

The team analyzed functional MRI scans of 180 "super-agers", people over 75 whose memory is comparable to that of 45-year-olds, and 110 patients with diagnosed Alzheimer's disease. The researchers identified differences in how the brain responds at rest in these two groups.

On this basis they created the Alzheimer's resilience-vulnerability connectome (ARC) scale. It distinguishes a "resilient" brain from a "vulnerable" one with an accuracy of about 85%. A plain comparison of healthy older people gives a blurred picture because biological anomalies among them are highly varied, so the specific super-ager pattern serves as a clearer reference. pravda.rupravda.rupravda.ruOpen source ↗

Follow-up in cognitively healthy adults

The scale was tested on more than 1,300 cognitively healthy people aged 55 to 70. At the start of observation they showed no differences in memory performance. Over follow-up of up to 12 years, those whose brain activity matched the "Alzheimer's" pattern had faster cognitive decline and a higher probability of amyloid plaque formation or a diagnosis.

Lead author Kanhao Zhao said the model shows predictive ability comparable to or better than existing biomarkers, but at an earlier stage.

The researchers state that the aim is not simply to diagnose the disease but to find early markers for potential timely interventions. The team is planning a clinical trial to test whether ARC values can be changed with cognitive training. Yu Zhang, associate professor at Stanford School of Medicine, said he is optimistic about reversing or preventing the process if such early indicators can be determined accurately. pravda.rupravda.rupravda.ruOpen source ↗

The ARC scale is not a diagnostic tool and does not determine a person's future unambiguously. Brain activity can change over time, with injury or other conditions. It has not been shown that altering these patterns, for example with cognitive training or transcranial magnetic stimulation, can prevent dementia.