A new study published in the Annals of Neurology – the official journal of the American Neurological Association – adds further evidence in support of our growing understanding that TBI, especially moderate/severe TBI or repetitive mild TBI, often triggers a “progressive neurodegenerative process” that accelerates over time. As discussed in prior posts, TBI is now conceptualized as potentially a chronic disease triggered by injury, not as an isolated event. Hopefully this understanding will lead in the future to interventions designed to halt or slow the disease process.
The recent study, published in the April 2015 issue, reports on the results of research at the Imperial College London, where brain scans of over 1500 healthy people were analyzed to develop a computer program that could predict a person’s age from their brain scan. The program was then used to estimate the “brain age” of 113 more healthy people and 99 people who had suffered TBIs. The brains of the TBI patients were on average five years older than their real age would predict.
Of particular note in the study was a correlation between time since injury and the predicted age difference – in other words, the age difference increased over time in the people who had suffered a TBI. This finding supports our understanding that the injury results in an ongoing biological process that can play itself out over a life time. Dr. Cole, the principal researcher, noted that
“Traumatic brain injury is not a static event. 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 differences in “brain age” also correlated with the degree of cognitive compromises, which turned out to be similar to the compromises seen in brains aging at a normal pace. This adds further support to the conclusion that the injury essentially accelerates aging of the brain.
It is important to note that the positive findings in this study were limited to patients with moderate and severe brain injuries and were not found with mild TBIs. (The study did not examine patients with multiple mild TBIs where other studies have noted progressive changes, such as studies of football players.)
Although this study can be seen as depressing news for TBI victims, especially victims of moderate/severe injuries, it does help direct future study of interventions designed to slow or halt this neurodegenerative process.