By R.J. Anderson
R.J. Anderson is an Assistant Editor at Coaching Management.
Coaching Management, 12.4, April 2004, http://www.momentummedia.com/articles/cm/cm1204/concussion.htm
Brandon Manning, a junior linebacker at Virginia Tech, is known for being in the right place at the right time. So his coaches were puzzled when they looked at the video following the team’s loss to West Virginia this past fall, and noticed Manning was often out of position during the second half.
Eventually, a coach turned to Manning and asked, "Brandon, what the heck were you doing on that play?" After careful consideration, Manning answered that he didn’t know—in fact, he didn’t even remember being on the field for that play. A few minutes later, he realized that he was seeing many parts of the game for the first time.
After getting over their surprise, coaches relayed word of Manning’s amnesia to the sports medical staff, who quickly went to their computers. During the game, Manning wore one of eight helmets outfitted with the Head Impact Telemetry (HIT) System, a wireless, impact-measuring device. The helmet contained six tiny accelerometers similar to the sensors used to trigger air bag deployment during automobile accidents. The sensors gathered information about the force and directionality of each blow to the helmet and transferred the data to a microchip imbedded inside the crown of the helmet. The data was transmitted to a laptop computer on the sideline, where the information was stored for future study.
HIT System technology was used at Virginia Tech last season as part of a study to examine the types of blows football players receive and which types cause concussions. In Manning’s case, it also helped the sports medicine staff uncover a concussion they otherwise would have missed.
Examining the readings from Manning’s helmet, the medical staff saw that a relatively high load had been recorded during the first half. They then matched the game video to the HIT System data and viewed the impacts which led to Manning’s concussion: a helmet-to-helmet collision with West Virginia tailback Quincy Wilson, followed by Manning’s head hitting the turf.
To Manning, the hit seemed no different than any of the other blows he had absorbed during his career. He didn’t leave the field and never reported anything to the coaches during or after the game. Had he not been wearing the HIT System-equipped helmet, Manning would have been viewed as a player having a bad day instead of becoming the first person to have a concussion recorded by the technology.
In the future, these concussions may even be caught as they happen, instead of through video the next day. "The technology is spectacular, because for the first time it allows us to evaluate these hits in real time," says Dr. Gunnar Brolinson, Team Physician for Virginia Tech football. "It’s an opportunity to prevent players from sustaining additional blows to the head after having sustained a concussive load to the brain."
Hits measured in real time? Accelerometer sensors? Microchips in helmets? Concussion-reading computers? These are major changes from a time not long ago when people would shrug off bell ringers and when displays of confusion or impaired coordination elicited laughter instead of concern. Recent efforts by the sports-medicine community have convinced most coaches that concussions are a serious matter, as have the concussion-induced retirements of several high-profile NFL players. But when it comes to the exact hows and whys of concussions, even the experts have had more questions than answers.
A series of research projects have shed fresh light on concussions, giving doctors new perspective on assessing the injury and breaking new ground on treatment ideas. As a result, coaches who have athletic trainers at their side may hear some new terms and see new procedures, while coaches without regular access to an athletic trainer may find much of what they thought they knew about concussions has changed.
As more attention becomes focused on concussions, more specific knowledge is being delivered. In 2003, the Sports Concussion Program at the University of Pittsburgh Medical Center published several studies on concussions in high school athletes. Among the UPMC findings was information that high school athletes take longer to recover from initial concussions than do college athletes. The researchers found that even seven days after suffering a concussion, high school athletes still reported significant symptoms, such as headaches and nausea, and performed worse on neurocognitive tests than those who were uninjured. In the study, college athletes typically returned to near-normal levels within three days, despite suffering more serious injuries.
Other studies have called into question traditional concussion evaluation for athletes of all ages. In a study published in March of 2003, researchers led by David Erlanger found that amnesia—as opposed to loss of consciousness—was the most important symptom for measuring severity. "Self-reported memory problems apparent 24 hours postconcussion … should be a primary consideration in determining an athlete’s readiness to return to competition," the article concluded. "Neither a brief loss of consciousness nor a history of concussion was a useful predictor of the duration of postconcussion symptoms."
A UPMC study found similar results. "Our study showed that many athletes with mild concussions whose symptoms disappeared within 15 minutes still showed significant decline in memory processing and other symptoms within one week after the injury, which means they weren’t healed," says Mark Lovell, Director of the Sports Concussion Program at UPMC.
Based on the research, Lovell and his colleagues believe that the traditional methods of assessing concussions need to change. "You want to find out if the player remembers what happened during the five or 10 minutes before and after the injury," says Lovell. "Ask the athlete to remember three words. Ask them to recount details of what happened to them. We think it’s very, very important to evaluate that on the field at the time of the injury. If we can detect any amnesia on the field, if there’s any detectable mental status change, if they have a significant headache, or if their balance is off, then we hold them out for the rest of the contest."
The reason assessing concussions is so critical was demonstrated in a study conducted by Kevin Guskiewicz, Director of the Sports Medicine Research Laboratory at the University of North Carolina. The study showed that once an athlete suffers a concussion, the probability that he or she will experience a second concussion during the same season is greatly increased. The study also indicates that recovery is slower in players with a history of previous concussions. The effects of multiple concussions can also linger, as the study showed that players with a history of three or more concussions are three times more likely to experience the injury again compared to players with no history of concussions.
Guskiewicz notes that 30 percent of injured players with three or more previous concussions had symptoms lasting longer than a week, compared with seven percent of those with no history of concussion. Researchers also found that 92 percent of repeat concussions occurred within 10 days of the initial injury.
"This underscores the critical importance of making certain that athletes are without symptoms before they are allowed to return to participation," says Guskiewicz. "Concussed players often will still be vulnerable during the first few days following the injury, but they are unlikely to sit out unless a physician or athletic trainer holds them out."
In Guskiewicz’s study, of 2,905 football players at 25 colleges, nearly 200 concussive injuries were reported. A total of 184 players (6.3 percent) experienced a concussion during that period, and 12 players suffered at least two. Positions that incurred the most concussions were linebackers, offensive linemen, and defensive backs.
While many of the recent studies examined the effects of concussion-inducing collisions, the next wave of research concentrates on the biomechanics involved with concussion-causing impacts. The first of these studies was directed by Elliot Pellman, Chair of the NFL Committee on Mild Traumatic Brain Injury (MTBI), and Team Physician for the New York Jets. The purpose of the research was to break down the impacts that caused 182 significant head injuries and concussions by utilizing NFL game footage. A cinematographic analysis was developed to determine the speed at which the players were moving prior to the concussion-causing collision. In 31 of the incidents, footage containing multiple camera angles of the impact was available. These viewings also allowed the researchers to perform three-dimensional laboratory reconstructions using helmeted crash-test dummies.
The results indicated that concussions are more likely to result when an impact causes the head to move in a straight line, rather than from the neck twisting. The footage also revealed that most concussions occurred when players were hit on the side of the helmet, on the facemask, or when the back of the helmet absorbed the impact.
The Pellman study is considered to be a milestone for concussion research, as it is the first to look at the speed of impact and the amount of head acceleration that occurred on impact. With a precedent now set, other groups are set to carry that research a step or two further. One such group is at Virginia Tech, where Manning and his teammates are helping researchers gauge the speed and directionality of the blows they receive. While Pellman and the MTBI Committee painstakingly worked to estimate and re-enact the impact in a laboratory, the medical staff and engineers at Virginia Tech aim to measure the impacts in real time as they occur on the playing field.
Capturing the Data
The Virginia Tech project was implemented at the beginning of the 2003 season. Every two weeks, the sensors were rotated to eight different players who wore them in their helmets during both practice and games. By the end of the season, 38 players had worn helmets equipped with HIT System sensors.
The sensors are designed to track a range of blows, which are measured in gravitational forces (g’s) with ranges from 15 to 150 g’s. "An impact of 120 g’s would be like a severe car accident, which you could survive while wearing a seat belt," says Stefan Duma, Director of the Virginia Tech-Wake Forest Center for Injury Biomechanics. Half of the blows registered by the HIT System measured more than 30 g’s, while blows exceeding 150 g’s were rare, but did occur.
"We rotated the sensors because we’re trying to get a valid assessment of which position is taking what kind of blows," says Brolinson, adding that the system captured the data from over 3,300 high-impact blows during the season. "One of the things I think is going to come out of this study is the need for position-specific helmets. We’re seeing that linemen sustain certain kinds of loads compared with defensive backs, running backs, and so on. We already have position-specific shoulder pads, why not position-specific helmets too?"
One particular finding that surprised Brolinson and his colleagues was the high number of hits that offensive and defensive linemen experience during a game. "It was not unusual for our linemen to sustain 50 or 60 significant blows during a game," he says.
Brolinson says he would like to use follow-up studies to find the effect of repeated nonconcussive blows. "We see multiple loads occurring with linemen," he says. "They are below the level of concussion, but almost any linemen that you talk to—high school, college, or professional—will tell you that a lot of them have headaches following games. We have previously thought these headaches were simple muscle tension headaches, and that may in fact be the case, but at this point given the number of blows and amount of g-loading sustained over the course of a game, we want to investigate that more thoroughly."
Brolinson also wants to continue to discover what types of hits cause concussions. "Ultimately what we want to do is predict risk of concussion based on the directionality of the blow and the load that is sustained, and then evaluate the athlete accordingly," he says. "We want to identify what level of blow we need to be concerned about, even in a player who retains consciousness. If a player sustains a 120-g hit, what is his risk of significant brain injury? Is it 25 percent? Is it 50 percent? Is it 75 percent? We want to identify the at-risk player based on the magnitude of the blow, and we would also like to identify the at-risk player based on the cumulative blows."
The directionality of the blow, Brolinson stresses, is just as important in causing a concussion as the force of the impact. A player who sustains a 130-g frontal impact might walk away from the play without a concussion, while the same player could take a 70- or 80-g lateral or posterior blow that could leave him with concussion symptoms. It is one of the variables their study is exploring—using risk modeling to decode concussion-causing impacts.
"Once we accumulate enough data to build these logistic models, we’ll have the ability to look at an 80- or 90-g blow, see where it comes from, and keeping in mind who it’s happening to, have an idea of what their risk of concussion is," says Brolinson. "If that’s somebody with, for example, a 75 percent risk of concussion, then we can immediately get him to the sideline. And if the sideline evaluation indicates he has a concussion, then we can take him out of the game and avoid subjecting him to further risks." During the 2003 season the HIT System was used primarily as a research-gathering tool, but by next season, Virginia Tech plans to outfit 64 helmets with accelerometers and begin using the system to help diagnose concussions.
While the current cost of this technology is prohibitive for smaller colleges and high schools—equipping a team of 50 to 75 players would cost $165,000 to $195,000 says Rick Greenwald, President and co-founder of Simbex, the company that manufactures the HIT System—Brolinson is confident that over time, the HIT System will be accessible for more mainstream use. Brolinson also hypothesizes that perhaps one day, hospital emergency rooms will be outfitted with the software to read the accelerometer chips, making it unnecessary for high schools to purchase the diagnostic technology. Then, if a player takes a hit that the athletic trainer believes could be concussive, the player’s helmet can be taken to the emergency room to have the impact tested. Brolinson feels this scenario is feasible for a variety of helmeted activities such as hockey, cycling, and skateboarding, because the sensors and chips are relatively inexpensive to produce.
Take Home Message
The best news about this research is that many of the findings can be translated into new assessment techniques right now. The biggest change is a move away from the grading scales that had been used to determine the severity of a head injury.
Although Lovell played a big part in developing some of the early concussion grading scales, he no longer endorses their use. "Those scales were based on arbitrary criteria. They weren’t based on any science," says Lovell. "They were a best guess of everybody out there at the time."
Instead, researchers suggest focusing more on individualized testing and using as many tools as possible. Those tools include balance testing, awareness testing, and knowing the athletes.
Virginia Tech currently uses a stabilogram, which measures a player’s balance and physical stability, and a Web-based neuropsychological exam called HeadMinder, which measures neurocognitive skills such as reaction time and memory retention. "All of that can be done on a sideline or in a locker room which allows the medical staff to make a well-calculated decision on whether or not to return that player to the game," says Brolinson.
Despite all the modern tools and methods that have been developed to detect a concussion, an old stand-by remains helpful. While doctors and athletic trainers can devise objective ways to read what an athlete’s body is saying, a coach can often receive the same signals in more subjective ways. So when a rock-solid linebacker makes an incorrect read on three straight plays or a reliable receiver runs a couple of wrong routes, coaches need to realize that the player may not be suffering from a lack of concentration—he may have a concussion.
"It is very important to understand that any change of behavior can be indicative of a concussion," says Collins. "Things to look for include whether their behavior has changed, if they’re exhibiting any level of confusion, if there are subtle personality changes, if the athlete is not playing like they normally play, or if the athlete is a little slower to react than usual.
"The worst cases of concussion occur when you have an athlete who has a mild concussion and chooses to not report his symptoms, goes back to play and has another injury," he continues. "The brain is not ready to get hit again, and when they have the second blow before the first has healed, the effects can result in more long-term types of problems—even death."
Once a player has been confirmed to have a concussion, coaches usually defer the return-to-play decision to doctors or athletic trainers. These decisions have changed from being based on largely subjective criteria to more objective criteria obtained through testing.
Coaches also should be aware of the tools used to determine when an athlete can return to play. There are a variety of computer-based examinations available, but the basic premise of each is for the athlete to develop a baseline score based on neurocognitive factors that are affected by a concussion, such as reaction time, processing speed, problem solving, and memory. If an athlete is suspected of having a concussion, he or she re-takes the exam and the results are measured against their baseline score.
"In the high school setting, where there are more athletes per athletic trainer, I think the computer-based testing will become more and more important," says Timothy Neal, Head Athletic Trainer at Syracuse University. "In the college setting, I think the use of neuropsychological testing will be more of an adjunct to what people are already doing."
Another benefit of computer-based neuropsychological testing is the message it sends athletes about the seriousness of reporting their symptoms when they are injured. "They sit down and take a baseline test that goes over all the symptoms of concussion," Collins says. "And at that point a coach or athletic trainer can say, ‘Look guys, this is why we’re taking this test. If you have any symptoms, let us know and we’ll manage this sensibly.’"