How fast is your brain ageing? Scientists develop a revolutionary way to measure it

Researchers developed a groundbreaking method to track brain ageing pace using deep learning and MRI scans, providing insights into cognitive decline.

A new study has found a game-changing way to track how fast our brains are ageing, not just how old they seem. Using advanced deep learning and MRI scans over time, researchers have developed a method to measure the "pace of ageing" in the brain. This could be a major breakthrough in spotting early signs of cognitive decline and neurodegenerative diseases like Alzheimer's.

Study reveals a method to measure brain ageing pace using MRI scans and deep learning. (Pixabay)

Published in Proceedings of the National Academy of Sciences (PNAS), the research introduces a powerful 3D convolutional neural network (3D-CNN) that can estimate brain ageing with incredible accuracy, outpacing all previous methods.

"This is a novel measurement that could change the way we track brain health both in the research lab and in the clinic," said Andrei Irimia, associate professor at the USC Leonard Davis School of Gerontology, in a statement. "Knowing how fast one's brain is ageing can be powerful."

While chronological age is fixed, biological age varies, some brains age faster or slower than expected. Earlier methods estimated "brain age" from a single MRI scan, offering only a static snapshot. Now, researchers have developed a way to measure the pace of brain ageing, providing deeper insight into brain health.

How the study measures brain ageing

"The pace of brain ageing reflects how quickly neurobiological integrity declines," the study notes. "A faster pace means greater cognitive decline, increasing risks of morbidity and mortality." Most biological age measures rely on blood samples to track epigenetic ageing, but that doesn't work for the brain. "The blood-brain barrier prevents blood cells from directly reflecting aging-related brain processes," explained Irimia.

The study introduces a deep learning approach to measure brain ageing speed. (Pexels)

USC researchers trained their model on MRI scans from over 2,000 healthy adults, validated it on 1,300 more, and tested it on patients with and without Alzheimer's. Unlike older methods that provide a single brain age estimate, this approach compares two MRI scans over time to calculate the pace of brain ageing. The result? Unmatched accuracy, just 0.16 years of error, compared to the previous model's 1.85-year error.

Beyond tracking ageing speed, the researchers used deep learning to identify which brain regions aged faster in different groups. "The 3D-CNN also generates saliency maps that highlight the most crucial brain regions for determining the ageing pace," explained Paul Bogdan, associate professor at USC Viterbi School of Engineering.

Key findings on brain ageing patterns

The study revealed distinct brain ageing patterns based on sex and age. In healthy females, ageing was most prominent in the right precentral gyrus, postcentral gyri, and superior parietal lobules, while males showed more changes in the left transverse frontopolar gyrus and right supramarginal gyrus.

The approach shows promise in identifying early signs of neurodegenerative diseases. (Pixabay)

Age also played a role, people in their 50s had more ageing in the left lateral temporal and right medial occipital lobes, while those in their 70s showed accelerated ageing in the right central and postcentral gyri and left cingulate gyrus.

Crucially, a faster pace of brain ageing is strongly correlated with cognitive decline. "A high rate of brain ageing often means a faster decline in memory, executive speed, and processing ability," Irimia explained. This was evident in the Alzheimer’s Disease Assessment Scale (ADAS13), where those with accelerated brain ageing showed greater cognitive deterioration. "Our method could serve as an early biomarker for neurocognitive decline," Bogdan added.

Potential for early detection and intervention

Researchers found that their pace of ageing measurements could predict cognitive decline. Among participants, 31 developed impairment after follow-up MRIs, while 211 remained healthy. Those who later declined had a significantly faster pace of brain ageing.

Detecting rapid brain ageing early could allow for preventive treatments or lifestyle changes to slow cognitive decline. Irimia sees this as a potential breakthrough, especially since current Alzheimer's drugs may be less effective when started too late.

The study also highlighted gender differences in brain ageing, which may explain varying neurodegenerative risks. While more research is needed, this approach could help us not only live longer but maintain healthier brains.

Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. Always seek the advice of your doctor with any questions about a medical condition.