Engineer helping unravel mystery of traumatic brain injury

The American Academy of Neurology issued new guidelines last week for assessing school-aged athletes with head injuries on the field. The message: if in doubt, sit out.

With more than 3 million sports-related concussions occurring in the U.S. each year, from school children to professional athletes, the issue is a burgeoning health crisis.

While concussions may not be difficult to diagnose initially, the longer one waits, the more difficult treatment can be.

The efforts of a researcher and his colleagues at Washington University in St. Louis’ School of Engineering & Applied Science are helping to unravel the many mysteries of traumatic brain injury.

“There’s and urgent need to understand the problem of traumatic brain injuries, for the sake of athletes, military personnel and accident victims,” says Philip Bayly, PhD, the Lilyan and E. Lisle Hughes Professor of Mechanical Engineering.

“Anyone who has met someone who’s had a head injury knows how scary it is, and how frustrating it is that we know so little about the causal pathways, and thus the best therapeutic opportunities,” he says.

Bayly, chair of the Department of Mechanical Engineering & Materials Science, researches the mechanics of brain injury. He recently received a $2.25 million grant from the National Institutes of Health to better understand traumatic brain injuries.

Head injuries, concussions and the resulting trauma have been in public discussion recently as the National Football League (NFL) deals with a lawsuit regarding head injuries by about one-third of living former NFL players. The league is accused of not providing information connecting football-related head injuries to brain damage, memory loss and other long-term health issues.

Bayly’s team is working on ways to measure 3-D relative motion between in the brain and skull and estimate strain during mild head acceleration. Bayly hopes computer simulation can teach researchers about the basic physics of brain injury and ways to develop new approaches to prevention and therapy.

“Our studies provide experimental data on how the brain actually responds mechanically in response to mild external loads,” Bayly says. “This is especially critical to developing useful computer simulations, to make sure they reflect reality.
These simulations will in turn be used to design new equipment, evaluate rule changes in sports and determine exposure thresholds or diagnostic tests.”

Computer simulation is important in creating animal models that can be used to develop diagnostic and therapeutic approaches, he says.

“Understanding mechanical deformation in traumatic brain injury is also essential to anyone studying brain trauma by exposing cultured brain cells to mechanical stress,” Bayly says. “We need to understand how much stress to apply and in what directions.”

How can athletes minimize their risks?

“From a mechanical standpoint, they should avoid repeated high head accelerations,” Bayly says. “Head-to-head collisions and collisions with head-to-ground are clearly to be avoided.”

Bayly says to truly protect athletes, new rules need to be instated.

“I would actually advocate for eliminating sports like boxing, in which injury-level accelerations are known to occur routinely. More research is needed on sports where the threshold is less clear.”

There is where Bayly and his colleagues come in.

“We need to do the research to find out what kinds of repeated accelerations are responsible for producing the degeneration seen in chronic traumatic encephalopathy,” he says.

(Image: Jupiterimages / Getty Images)

Computer Model May Help Athletes and Soldiers Avoid Brain Damage and Concussions

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.”

Why your brain tires when exercising

A marathon runner approaches the finishing line, but suddenly the sweaty athlete collapses to the ground. Everyone probably assumes that this is because he has expended all energy in his muscles. What few people know is that it might also be a braking mechanism in the brain which swings into effect and makes us too tired to continue. What may be occurring is what is referred to as ‘central fatigue’.

"Our discovery is helping to shed light on the paradox which has long been the subject of discussion by researchers. We have always known that the neurotransmitter serotonin is released when you exercise, and indeed, it helps us to keep going. However, the answer to what role the substance plays in relation to the fact that we also feel so exhausted we have to stop has been eluding us for years. We can now see it is actually a surplus of serotonin that triggers a braking mechanism in the brain. In other words, serotonin functions as an accelerator but also as a brake when the strain becomes excessive," says Associate Professor Jean-François Perrier from the Department of Neuroscience and Pharmacology, who has spearheaded the new research.

Help in the battle against doping

Jean-François Perrier hopes that mapping the mechanism that prompts central fatigue will be useful in several ways. Central fatigue is a phenomenon which has been known for about 80 years; it is a sort of tiredness which, instead of affecting the muscles, hits the brain and nervous system. By conducting scientific experiments, it is possible to observe and measure that the brain sends insufficient signals to the muscles to keep going, which in turn means that we are unable to keep performing. This makes the mechanism behind central fatigue an interesting area in the battle against doping, and it is for this reason that Anti Doping Danmark has also helped fund the group’s research.

"In combating the use of doping, it is crucial to identify which methods athletes can use to prevent central fatigue and thereby continue to perform beyond what is naturally possible. And the best way of doing so is to understand the underlying mechanism," says Jean-François Perrier.

Developing better drugs

The brain communicates with our muscles using so-called motoneurons. In several diseases, motoneurons are hyperactive. This is true, for example, of people suffering from spasticity and cerebral palsy, who are unable to control their movements. Jean-François Perrier therefore hopes that, in the long term, this new knowledge can also be used to help develop drugs against these symptoms and to find out more about the effects of antidepressants.

"This new discovery brings us a step closer to finding ways of controlling serotonin. In other words, whether it will have an activating effect or trigger central fatigue. It is all about selectively activating the receptors which serotonin attaches to," explains Jean-François Perrier.

"For selective serotonin re-uptake inhibitor (SSRI) drugs which are used as antidepressants, we can possibly help explain why those who take the drugs often feel more tired and also become slightly clumsier than other people. What we now know can help us develop better drugs," concludes Jean-François Perrier.

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FOOTBALL teams of the future — even high school squads on limited budgets — may someday have a new tool to check players for brain injuries. It’s a special form of headgear, packed with sensors that read the brain waves of athletes after they come off the field, thus detecting changes caused by the trauma of hard knocks.

The compact, portable sensors decipher neural activity by measuring changes in the brain’s tiny magnetic field. These small magnetometers — still in the laboratory and in prototype — have yet to be tried on athletes. But their potential is enormous for brain imaging and for inexpensive monitoring of brain diseases, as well as for many other applications like the control of prosthetics, said Dr. José Luis Contreras-Vidal, a professor of electrical and computer engineering at the University of Houston.