Your brain’s age might be older than your body, creating a "brain age gap"

Most of us know our birthday, but our brains may not follow the same calendar. Scientists now compare a scan-based brain age with our actual age to find what’s called a “brain age gap.” A larger gap can hint at slower thinking and weaker memory.

The study included 1,437 Southeast Asian adults, all without dementia, with an average age of 66. Of this group, 60 percent showed no signs of cognitive impairment.

Each participant provided medical history through interviews, questionnaires, and medication reviews. They also underwent physical exams, lab tests, and brain imaging.

“As we get older, our brains change,” said study co-author Dr. Saima Hilal of the National University of Singapore.

“With less brain volume and fewer blood vessels that support brain tissue, diseases can worsen these changes, profoundly affecting brain health.”

How brain age is calculated

Using modern MRI scans, scientists fed data into a machine-learning model trained to estimate the biological age of a person’s brain.

The experts then subtracted the individual’s real age from this predicted age to find the brain age gap. A positive number meant the brain appeared older than the person’s actual age.

The research team also looked at each person’s brain scans for tiny signs of cerebrovascular disease – such as microbleeds or areas of dead tissue – caused by reduced blood supply.

Risk factors and cognitive performance

To understand the likelihood of cognitive impairment, the researchers assigned each participant a risk score.

This score factored in age, ethnicity, education level, past and current smoking, body mass index, depressive symptoms, high blood pressure, diabetes, high cholesterol, and any history of stroke. A higher score indicated a greater risk of impaired thinking and memory.

The participants then completed a series of cognitive tests. These measured various mental skills including executive function, attention, language, and memory.

The experts also assessed visuoconstruction (such as the ability to copy a drawing) and visuomotor speed, which involves processing visual information and responding with movement.

The researchers found that higher risk scores consistently aligned with lower scores on these tests -especially in tasks involving visuoconstruction and visuomotor speed.

AI links brain age and risk

Once the researchers had each participant’s brain age, they explored whether the brain age gap played a role in how health risks affected thinking and memory. In many cases, it did.

Among participants with more signs of cerebrovascular disease, the brain age gap had a stronger influence. It appeared to magnify how much health risks affected areas like executive function and language.

Researchers calculated how much of the connection between risk factors and cognition could be explained by the brain age gap. They found that it accounted for 20 percent of the overall link.

It explained 34 percent of the link to executive function and 27 percent of the link to language skills.

“The brain age gap may be a helpful biomarker in determining a person’s risk of cognitive decline,” said Hilal.

“Our findings suggest that accelerated brain aging may serve as an important factor linking cognitive impairment risk factors to thinking and memory skills in adults with cerebrovascular conditions.”

Using brain age to guide treatment

This research could help doctors spot early warning signs of cognitive decline, especially in people with known health risks.

A simple scan that shows the brain is aging faster than it should could encourage earlier treatment or lifestyle changes. It may also help identify individuals who are more vulnerable to rapid cognitive decline, even if they currently show no outward symptoms.

Over time, brain age analysis could become a useful tool alongside traditional checkups, offering a more complete picture of neurological health.

A few limits to consider

It’s worth noting that the study focused only on Southeast Asian participants, so the results may not apply to all populations.

Also, data on diet, exercise, and certain genes tied to Alzheimer’s disease were not available for all individuals, limiting some of the analysis.

Longer studies will be needed to see how brain age gaps change over time and whether they can help predict future memory decline.

The full study was published in the journal Neurology.

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