Virtual-Reality Test Reveals Hidden Concussion Damage
A technology that can tell when athletes are ready to get back in the game
Photo: Elena Slobounov
To assess athletes' injuries, scientists measure motion and brain waves in response to virtual situations.
Autumn is upon us, and in the United States, so is football season. The players, who deliver jarring hits to one another that often equal the force of car wrecks, are lionized for the ability to, in the words of an old watch commercial, ”take a licking and keep on ticking.” But concussions are not uncommon, and new research shows that even when players are symptom-free and have passed a battery of cognitive-function tests, their brains may not have completely recovered and may still be vulnerable to further injury.
An ongoing study at Pennsylvania State University aims to create a reliable electroencephalography system for judging whether an athlete should get back in the game, stay on the sidelines, or call it quits.
In an early round of the study, to be published in IEEE Transactions on Neural Systems and Rehabilitation Engineering , 61 football, rugby, and soccer players at Penn State (male and female) were examined; 30 of them were chosen because they had suffered concussions 30 days prior to participating in the study but had been cleared for a full return to their sports. Each subject was connected to an electroencephalograph via 19 electrodes attached to his or her scalp and earlobes and was asked to stand on a platform studded with sensors that recorded shifts in pressure distribution at the bottom of the feet. The platform was surrounded on three sides by video screens that created a visually immersive environment.
A computer running a proprietary algorithm recorded and synchronized the subjects'; physical and neurological responses to virtual-reality graphics. The graphics were designed to give participants the sense that they were involved in some situation that provokes a physical response—say, riding a roller coaster or participating in a snowball fight.
The control group, made up of players who had not suffered concussions, mostly did what was expected when presented with virtual situations that called for complicated, coordinated responses using multiple body parts, and their brain-wave patterns were ordinary. Using the control data, the system became increasingly adept at identifying previously concussed athletes, who exhibited delayed reaction times and abnormal physical reactions like using too little or too much force. Nearly 97 percent of the time, these abnormalities in motor coordination corresponded to detectable differences in the athletes'; brain waves compared with baseline readings taken before the start of their competitive seasons.
According to research associate Richard L. Tutwiler, the Penn State researchers are refining the technique and gathering a pool of data they think will be large enough to yield a reliable brain assessment tool within two years. ”The hope is that we can then make a portable unit that can begin taking readings right after a player gets off the field,” he says.
Stefan Duma, director of Virginia Polytechnic University';s Center for Injury Biomechanics and the lead researcher on the Head Impact Telemetry program (HIT), applauds the Penn State researchers'; efforts. The HIT system, developed by researchers at Simbex, of Lebanon, N.H., and at Virginia Tech and Brown universities, uses helmet-mounted sensors to measure the force of collisions. It then alerts coaches and trainers to those collisions likely to have resulted in concussions, based on data from more than 30 000 impacts. [See ”Helmets Sense the Hard Knocks,” IEEE Spectrum, October 2007.]
Jeffrey Chu, Simbex';s director of engineering, says that Penn State';s test and HIT would be complementary technologies. ”HIT gives sideline staff a powerful tool by putting the focus on players likely to have suffered a brain injury,” says Chu. ”A device based on EEG or other assessment tools would pick up from there, determining the extent of the damage.”