Researchers at Imperial College London analysed brain scans from over 1,500 healthy people to develop a computer program that could predict a person's age from their brain scan. Then they used the program to estimate the "brain age" of 113 more healthy people and 99 patients who had suffered traumatic brain injuries.
The brain injury patients were estimated to be around five years older on average than their real age.
Head injuries are already known to increase the risk of age-related neurological conditions such as dementia later in life. The age prediction model may be useful as a screening tool to identify patients who are likely to develop problems and to target strategies that prevent or slow their decline.
"Your chronological age is not necessarily the best indicator of your health or how much longer you will live," said Dr James Cole, who led the study, from the Department of Medicine at Imperial College London. "There is a lot of interest in finding biomarkers of ageing that can be used to measure a certain aspect of your health and predict future problems."
The study, published in the April issue of Annals of Neurology, used magnetic resonance imaging (MRI) to study changes in brain structure. The researchers used a machine learning algorithm to develop a computer program that could recognise age-related differences in the volume of white matter and grey matter in different parts of the brain.
The model was then used to estimate subjects' ages based on their brain scans. The study included 99 patients with traumatic brain injuries (TBI) caused by road accidents, falls or assaults, who had persistent neurological problems. The scans were taken between one month and 46 years after their injuries.
In healthy controls, the average difference between predicted age and real age was zero. In TBI patients, the difference was significantly higher, with a bigger discrepancy in patients with more severe injuries. Bigger differences in predicted age were associated with cognitive impairments such as poor memory and slow reaction times.
There was also a correlation between time since injury and predicted age difference, suggesting that these changes in brain structure do not occur during the injury itself, but result from ongoing biological processes, potentially similar to those seen in normal ageing, that progress more quickly after an injury.
"Traumatic brain injury is not a static event," said Dr Cole. "It can set off secondary processes, possibly related to inflammation, that can cause more damage in the brain for years afterwards, and may contribute to the development of Alzheimer's or other forms of dementia."
The researchers believe the age prediction model could be applied not just to TBI patients, but might also be useful to screen outwardly healthy people.
"We want to do a study where we use the program to estimate brain age in healthy people, then see if the ones with 'old brains' are more likely to get neurodegenerative diseases. If it works, we could use it to identify people at high risk, enrol them in trials and potentially prescribe treatments that might stave off disease," said Dr Cole.
The researchers received funding from the EU Seventh Framework Programme and a National Institute for Health Research (NIHR) professorship for Professor David Sharp. The research was also supported by the NIHR Imperial Biomedical Research Centre.
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Notes to editors:
1. J.H. Cole et al. 'Prediction of brain age suggests accelerated atrophy after traumatic brain injury.' Annals of Neurology, 2015. DOI: 10.1002/ana.24367
2. About Imperial College London Imperial College London is one of the world's leading universities. The College's 14,000 students and 7,500 staff are expanding the frontiers of knowledge in science, medicine, engineering and business, and translating their discoveries into benefits for society. Founded in 1907, Imperial builds on a distinguished past - having pioneered penicillin, holography and fibre optics - to shape the future. Imperial researchers work across disciplines to improve global health, tackle climate change, develop sustainable energy technology and address security challenges. This blend of academic excellence and its real-world application feeds into Imperial's exceptional learning environment, where students participate in research to push the limits of their degrees. Imperial nurtures a dynamic enterprise culture, where collaborations with industrial, healthcare and international partners are the norm. In 2007, Imperial College London and Imperial College Healthcare NHS Trust formed the UK's first Academic Health Science Centre. This unique partnership aims to improve the quality of life of patients and populations by taking new discoveries and translating them into new therapies as quickly as possible. Imperial has nine London campuses, including Imperial West: a new 25 acre research and innovation centre in White City, west London. At Imperial West, researchers, businesses and higher education partners will co-locate to create value from ideas on a global scale. http://www.imperial.ac.uk
3. About the National Institute for Health Research The National Institute for Health Research (NIHR) is funded by the Department of Health to improve the health and wealth of the nation through research. Since its establishment in April 2006, the NIHR has transformed research in the NHS. It has increased the volume of applied health research for the benefit of patients and the public, driven faster translation of basic science discoveries into tangible benefits for patients and the economy, and developed and supported the people who conduct and contribute to applied health research. The NIHR plays a key role in the Government's strategy for economic growth, attracting investment by the life-sciences industries through its world-class infrastructure for health research. Together, the NIHR people, programmes, centres of excellence and systems represent the most integrated health research system in the world. For further information, visit the NIHR website (http://www.nihr.ac.uk).