New study on the signs of brain ageing: variations linked to lifestyle and genetics

Not only wrinkles and white hair: ageing also leaves unmistakable signs in the anatomy of the brain, with areas wrinkling and others changing their structure. Five crucial changes have been identified so far, and recognising them has been anything but easy because they are imperceptible but inexorably real alterations that have precise links with lifestyle as much as with genetics. They were described in the journal Nature Medicine by a research team coordinated by the University of Pennsylvania and comprising artificial intelligence experts and biomedical image analysts.

What happens in the ageing brain are changes linked to particular conditions, such as Parkinson's, and being able to recognise them promises to make future diagnoses of neurodegenerative diseases more accurate. In order to be able to see the way the brain changes as it ages, it was necessary to analyse around 50,000 images obtained by nuclear magnetic resonance imaging. An artificial intelligence system was used for this.

"The human eye is unable to perceive the way changes occur" associated with cognitive decline, notes Christos Davatzikos, a biomedical imaging expert at the University of Pennsylvania in Philadelphia and author of the paper with Zhijian Yang, an expert in artificial intelligence applied to biomedicine at the same university. It took eight years to complete the first sweeping analysis that went beyond what had been done so far, which had resulted in partial studies conducted on a small number of individuals.

Helping the researchers was the artificial intelligence system called Surreal-Gan. First, however, it had to be trained and this was done by teaching the system to read the MRI data of 1,150 healthy people aged between 20 and 49 and 8,992 older adults, some of them with cognitive decline. This is how the AI system learned to recognise the signs of ageing and was ready to review the 49,482 MRI images collected from 11 studies. The result of this analysis led to the identification of five signs of brain ageing. Three of these, for example, are present in some forms of dementia, others in Parkinson's and Alzheimer's. The researchers' hope is that in the future these alterations may help predict the onset of dementia already in a healthy brain. Links have also been identified between the five alterations and lifestyles, such as smoking and alcohol consumption, or with genetic characteristics.