Many high school athletes with concussions who are medically cleared to return to play within 60 days of the brain injury will suffer significant setbacks in their recovery, says a new study by the University of Oregon. The athletes experienced significant regression in their ability to do simple mental tasks and walk at the same time. Currently, medical staff and team trainers often determine the time that athletes return to activity based on the athletes’ self-reported symptoms and individual assessments of the athletes’ motor or cognitive function. The study findings were announced on August 20, 2014, and were published in the journal Medicine & Science in Sports & Exercise.
The study was based on a closer analysis of data from an earlier 2013 study that was published in the journal Medicine & Science in Sports and Exercise. That research demonstrated that the 25 high school athletes with concussions had compromised abilities to switch tasks and to focus for up to two months after their injuries.
Performance assessments were done within 72 hours of the injuries, and again at one week, two weeks, a month, and two months after the concussion. Researchers excluded six athletes who did not to activities during the study period. At 28 days post injury, data suggesting a regression began to emerge, said principal investigator Li-Shan Chou, a professor in the UO Department of Human Physiology and director of the Motion Analysis Laboratory.
"We had seen this same type of curve in an earlier study of college athletes," Chou said. "We didn't have any evidence linking it to a return to activity, but we did discuss that possibility, because we knew that they usually were permitted to return to practice two weeks after a concussion."
The previous study had found that concussed athletes had a slower reaction time of 30 to 40 milliseconds two months after injury. "For many of us, that is just a blink of the eyes, but for athletes to be sure their bodily position is ready to perform a very skilful avoidance maneuver or prepare to safely take a collision, 30 milliseconds is a critical length of time for assuming that posture," he said.
In the current study, the 19 high school athletes analyzed in the current study represented football (13 athletes), soccer (4), wrestling (1), and volleyball (1). David Howell of the Boston Children's Hospital and lead author of the study, compared the return-to-activity status with the results of three tests: walking, doing simple computerized mental exercises, and a combination of walking and doing mental exercises simultaneously.
While performing the dual task test, walking athletes heard a spoken word and identified it as either a low or high-pitched tone. Other tasks done while walking were subtracting seven repeatedly beginning at 100 and reciting the months backward from October on. Researchers compared the results to a control group who did not suffer from a concussion.
The study found:
- 12 of the athletes had changes in their walking speeds and/or balance
- Out of the 12 athletes, 10 had returned to sports activity in less than a month
- Seven athletes whose performance was similar to uninjured control subjects returned to activity more than 20 days after suffering injuries
- The more complicated the secondary task done while walking, the more significant the effect on concussed athletes when compared to the uninjured control group
"There had been a continuous improvement prior to the athletes' return to activity," Chou said. "But at the data point taken after their return to activity, we saw a turn in their recovery in the opposite direction. When the athletes did a simple walking test, there was no regression. Just using the computer task to probe their cognitive functioning, we didn't see a regression. However, put together, we did."