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Look everywhere — a simple solution with a difficult execution. Gaser’s team used a machine learning algorithm to analyze 3D brain scans. Called BrainAGE, the algorithm is a novel method that provides researchers with an individual’s “brain age gap estimate” — that is, the gap between an individual’s chronological age and their brain’s functional age.
BrainAGE has become the most widely applied method for evaluating the neurological impact of an individual’s genetics, diseases, environment, and behavior. Lower BrainAGEs have been found in individuals who play music (likely due to increased blood flow, which delivers more nutrients), and higher BrainAGEs have been found in individuals diagnosed with Alzheimer’s.
Gaser’s team sought to use the BrainAGE method to determine if brain damage could be identified in individuals with elevated blood pressure before the onset of a neurological disease. To do so, the BrainAGE algorithm first was fed a couple thousand images of brains of various ages. Next, the program analyzed the brain scans of 686 participants and applied its newly acquired knowledge to predict the functional brain age of each (irrespective of the participant’s actual chronological age).
As predicted, the brains of individuals with optimal blood pressure (110/70 mmHg) appeared the youngest. However, they weren’t just younger than the brains of those with high blood pressure; they also appeared six months younger than the brains of individuals whose blood pressure was toward the high end of the normal range (135/85 mmHg).
These effect sizes may seem trivial — indeed, differences of 6.7 years have been observed between individuals with and without Alzheimer’s disease — but the researchers go on to explain that “an average difference of six months has high relevance as it can serve as an additional risk marker, which, if combined with other risk factors, may be predictive of premature conversion to dementia.”
Concerningly, the researchers also detected brain damage in participants in their 40s. Nicolas Cherbuin, lead author of the paper, said that “we have to assume the effects of elevated blood pressure must build up over many years and could start in their 20s. This means that a young person’s brain is already vulnerable.”
