Cognitive deficits from concussions present after two months

Left to right: Osternig, Chou and Howell studied high school athletes
Left to right: Osternig, Chou and Howell studied high school athletes

Conventional wisdom says a typical recovery from concussion takes seven to 10 days, said David Howell, a graduate student in the UO Department of Human Physiology.

But in a new study, Howell found that the ability to focus and switch tasks readily amid distractions was compromised for up to two months following brain concussions suffered by high school athletes. The study, which was picked up by mainstream media including Canada’s Globe and Mail, was co-authored with Li-Shan Chou, professor of human physiology and director of the UO Motion Analysis Laboratory, and Louis Osternig, professor emeritus of human physiology and a fellow of the American College of Sports Medicine.

The discovery suggests that some athletes may need longer recovery periods than current practices dictate to lower the risk of subsequent concussions.

"If a person goes back to the playing field without a full recovery, that person is put into great danger of being re-injured," Chou said. "In any given season, if you suffer a concussion, the chances of your suffering a second one is three to six times higher and suffering a third is eight times higher.”

The findings are based on cognitive exercises used five times over the two months with a pair of sensitive computer-based measuring tools — the attentional network test and the task-switching test. The study was published online ahead of print by Medicine & Science in Sports & Exercise, the official journal of the American College of Sports Medicine.

Each year, there are 300,000 to 500,000 mild traumatic brain injury incidents, or concussions, with 100,000 tied to football, Chou said. He also cited a 2011 report from the Centers for Disease Control and Prevention that called such injuries a silent epidemic, with sports-related concussions in youths rising by 60 percent in the last decade.

A big unknown, the researchers said, is just how serious such injuries are for adolescents, whose brains are still developing.

Through an arrangement with Eugene-area schools, 20 high school athletes who had suffered a concussion — primarily football players but also others from soccer, volleyball and wrestling — were assessed within 72 hours of injury and then again one week, two weeks, a month and two months later.

"After two months following the concussions, these individuals were still significantly impaired in their executive function, compared to age-matched, activity-matched and gender-matched control populations," Osternig said.

Osternig, also a certified athletic trainer, noted that self-reports by the subjects about how they were feeling sometimes were at odds with test results, which continued to show subtle deficits in cognitive functioning. The researchers also noted anecdotal reports from concussed athletes and their parents of declines in academic performance during the two-month period.