Concussions can occur in sports and in combat, but health experts do not know precisely which jolts, collisions and awkward head movements during these activities pose the greatest risks to the brain. To find out, Johns Hopkins engineers have developed a powerful new computer-based process that helps identify the dangerous conditions that lead to concussion-related brain injuries. This approach could lead to new medical treatment options and some sports rule changes to reduce brain trauma among players.
The research comes at a time when greater attention is being paid to assessing and preventing the head injuries sustained by both soldiers and athletes. Some kinds of head injuries are difficult to see with standard diagnostic imaging but can have serious long-term consequences. Concussions, once dismissed as a short-term nuisance, have more recently been linked to serious brain disorders.
"Concussion-related injuries can develop even when nothing has physically touched the head, and no damage is apparent on the skin," said K. T. Ramesh, the Alonzo G. Decker Jr. Professor of Science and Engineering who led the research at Johns Hopkins. "Think about a soldier who is knocked down by the blast wave of an explosion, or a football player reeling after a major collision. The person may show some loss of cognitive function, but you may not immediately see anything in a CT-scan or MRI that tells you exactly where and how much damage has been done to the brain. You don't know what happened to the brain, so how do you figure out how to treat the patient?"
To help doctors answer this question, Ramesh led a team that used a powerful technique called diffusion tensor imaging, together with a computer model of the head, to identify injured axons, which are tiny but important fibers that carry information from one brain cell to another. These axons are concentrated in a kind of brain tissue known as "white matter," and they appear to be injured during the so-called mild traumatic brain injury associated with concussions. Ramesh's team has shown that the axons are injured most easily by strong rotations of the head, and the researchers' process can calculate which parts of the brain are most likely to be injured during a specific event.
The team described its new technique in the Jan. 8 edition of the Journal of Neurotrauma. The lead author, Rika M. Wright, played a major role in the research while completing her doctoral studies in Johns Hopkins' Whiting School of Engineering, supervised by Ramesh. Wright is now a postdoctoral research fellow at Carnegie Mellon University. Ramesh is continuing to conduct research using the technique at Johns Hopkins with support from the National Institutes of Health.
Beyond its use in evaluating combat and sports-related injuries, the work could have wider applications, such as detecting axonal damage among patients who have received head injuries in vehicle accidents or serious falls. "This is the kind of injury that may take weeks to manifest," Ramesh said. "By the time you assess the symptoms, it may be too late for some kinds of treatment to be helpful. But if you can tell right away what happened to the brain and where the injury is likely to have occurred, you may be able to get a crucial head-start on the treatment."