NEW ORLEANS – A young athlete who has a diminished ability to walk and think at the same time after suffering a concussion may not be fully recovered and could risk another injury if he or she returns to play, suggests preliminary new research being presented today at the National Athletic Trainers’ Association (NATA) 69th Clinical Symposia & AT Expo.
Athletes who have suffered a concussion typically are cleared to return to play once they pass tests that measure balance, vision, movement and cognition (ability to think and reason). Experts theorize those assessments might miss lingering movement or attention deficits that could increase the athletes’ risk of getting re-injured. The small new study suggests an assessment that measures the ability to walk and think at the same time, called dual-task gait testing, might identify those deficits and could be an important addition to the protocol that determines when an athlete returns to play after a concussion. The dual-task gait tests are currently used to assess progression of conditions such as dementia and Parkinson’s disease.
“If we can determine that athletes have recovered this ability after concussion, they may be less likely to get re-injured,” said David Howell, PhD, ATC, lead author of the study, athletic trainer and lead researcher for the Sports Medicine Center at Children’s Hospital Colorado, Aurora. “Our study is the first to test the theory that subsequent injury risk is related to motor function and/or attentional deficits, which can be measured using dual-task tests.”
Dual-task gait testing measures walking patterns when a person walks normally, and then again while thinking through a problem, such as reciting the months in reverse order, spelling a word backwards or subtracting by 7s starting at 99. The difference in these gait measures between conditions, such as how fast a person walks, is called the dual-task gait cost, a measure of motor function. Walking and thinking at the same time causes everyone to slow down because the brain needs extra time to process and complete two tasks simultaneously, but those recovering from a concussion tend to slow down even more.
Motor function deficits increase the risk of getting injured because while on the field athletes need to run or walk while also navigating opponents and strategizing where to move at a rapid pace. Even subtle impairments may decrease the ability to move effectively during sports to reduce injury risk.
Conducted at Boston Children’s Hospital sports medicine clinic the study included 41 high school and college athletes (21 female, 20 male) who suffered a concussion while playing basketball, football, hockey or soccer, and eventually returned to play (which ranged from five days to four months). The researchers had each athlete complete the dual-task gait test within three weeks of the concussion and then again when cleared to return to their sport based on passing the tests that are part of the current concussion protocol.
Fifteen athletes were subsequently injured within a year after returning to play: four had another concussion while the others had knee dislocations, or hip or ankle sprains. Researchers then separated the athletes and results into two groups – those who had been re-injured and those who had not – and compared their collective first and second dual-task gait scores. They found the scores among the injured athletes had worsened between the first and second test, while among the non-injured athletes, the scores had not changed.
- For the injured athletes, the dual-task gait deficit was a 17.9 percent dual-task cost (change between walking alone vs. walking and thinking conditions) shortly after the concussion and 25.1 percent dual-task cost when they had been cleared to play.
- For non-injured athletes, the dual-task gait deficit remained similar: 25.8 percent dual-task cost shortly after the concussion and 25.1 percent dual-task cost when they had been cleared to play.
It’s the comparison between conditions in the same athlete that is telling, researchers said. Study authors say their findings need to be verified in a larger study and additional research is needed to determine how to decide when an athlete’s motor function has returned to normal. But this early research suggests dual-task gait testing can identify athletes who are continuing to struggle with worsening motor function deficits as a result of concussion, even though self-reported symptoms are improving.
The concern is even greater in children and adolescent athletes because the frontal lobe of the brain – which is responsible for the ability to complete two tasks simultaneously (such as walking and thinking) – is growing rapidly. That may suggest young athletes are even more vulnerable to these effects, researchers said.
“Athletic trainers are concerned about the safety of athletes and along with coaches and parents want to be sure these students are fully healthy before they return to play,” said Howell. “This early research sheds light on the complexities of the recovering brain and suggests that dual-task gait may be a paradigm worth looking at to reduce the risk of injury before clearing an athlete to return to play. The next step is to translate this research into something athletic trainers can easily use to assess athletes.”