WEDNESDAY, Nov. 30, 2011 (HealthDay News) -- New research shows how a concussion can cause damage in a young athlete's brain that may last longer than thought.
In a preliminary study of 12 children with sports-related concussions, the majority experienced immediate decreased blood flow to their brains. Nearly two-thirds showed persistent, significant differences compared to non-injured athletes after two weeks, and one-quarter still had low blood flow to the brain more than a month after the injury occurred.
"In general, we think decreased cerebral blood flow leads to decreased delivery of nutrients such as oxygen and glucose to the brain," explained study author Dr. Todd Maugans, a faculty member at the University of Cincinnati. And weaker blood flow, in itself, could affect brain function, he said.
The good news is that specialized MRIs found no structural damage -- such as chemical changes, brain bleeds or torn nerves -- in any of the 12 children (nine boys and three girls) with concussions from football, wrestling or soccer. Twelve additional children who had no concussions served as controls for the study.
The 24 children in the study, aged 11 to 15, completed computerized tests to measure reaction time, verbal memory, visual memory and visual motor speed. In the first three days after being injured, children with concussions had slower reaction times than those in the control group. By two weeks, the gap had narrowed and, after a month, there was no significant difference.
The study appears online Nov. 30 and in the January 2012 print issue of Pediatrics.
"In high school football players, about 6 percent of kids get concussions in a season. On a team of 60 players, about three will be affected in a season," said Dr. Matt Grady, a pediatric sports medicine specialist at the Children's Hospital of Philadelphia.
The new study's message is "that pediatric concussion is slightly different from adult models," Grady said. "The power of this study is that we need to let kids rest and reduce metabolic demands on the brain."
His advice to young concussion patients: "Stay out of school the first week after a concussion if you're still having symptoms. It's called 'cognitive rest.' No schoolwork, no text messaging, no video games, no homework. Nothing requiring intense concentration."
It's important to get enough rest to avoid a second concussion before the first has resolved, Maugans explained.
"If blood flow is low, another injury could be a catastrophe," said Maugans, who also is a pediatric neurosurgeon at Cincinnati Children's Hospital Medical Center. "'Second injury syndrome' can occur in children and young adults after two seemingly minor concussions and result in serious brain damage or death."
Fortunately, it's very rare, he said, with one or two cases reported a year.
To document the link between concussion and reduced blood flow, "we need a larger study for cause-and-effect," said Maugans, whose next study will include many more children and test them with a form of ultrasound "that can be done in seconds while the child is sitting on the bench."
A second Pediatrics study found that computerized concussion testing is used in about 40 percent of schools that employ athletic trainers. Significantly, in those schools, athletes with concussions were less likely than others to return to play within the next 10 days.
"Ideally, it's administered before the start of the season," said study author Dr. William Meehan, director of the Sports Concussion Clinic at Children's Hospital Boston. "An athletic trainer tells kids how to proceed -- they sit in front of a computer for about 30 minutes. Now you have an idea of how the kid functions before being at risk of injury, and you can compare. Still, the majority of high school athletes don't have baselines."
The software costs several hundred dollars, he said. "Optimal concussion care involves using these tests, but it's not a yes-no," he said. "Really, they're one piece of information used in conjunction with other things," such as physical exams and assessing a child's emotional status."
Many parents want to know how to prevent head injuries, such as whether it's worth investing in expensive helmets marketed as "concussion-prevention systems."
"There is no 'concussion-proof' helmet," Grady said. "Helmets are great at preventing skull fractures. They help when your head hits the ground. But neck muscles probably do more to prevent concussions. If you see a hit coming and brace for it, you may be able to walk away without any concussion. But if you get an upward injury to your chin it could cause violent shaking -- and concussion is a shaking injury."
Maugans recommends "good play: not spearing, not head-butting. Following rules of play, physical conditioning, good nutrition, good hydration. People who are dehydrated are already at risk of low cerebral blood flow."
"At games, there's often an EMT or trainer on the sidelines," Meehan said. "If your child is unconscious, sleepy, confused, vomiting -- get them to the ER."
Concussion warning signs include "headache, nausea, the kid is bothered by loud noises or bright lights," Grady said. "More irritability, subtle changes in personality. All cylinders don't seem to be firing."
The U.S. Centers for Disease Control and Prevention has more on concussion in sports.