Sept. 21, 2000 -- Diehard sports fans admire athletes who get knocked for a loop but manage to stagger onto their feet and get back into the game. But here's a sobering thought for soccer moms and dads, or anyone who cheers on kids at play: Even a so-called 'mild' concussion could impair children's ability to learn and develop to their full intellectual potential, warn brain researchers in the September issue of the Journal of Neurotrauma.
Injuries to the brain that occur during a critical "window" of development may close that window forever, suggest David Hovda, PhD, and colleagues from the division of neurosurgery and the Brain Injury Research Center at the University of California, Los Angeles.
A concussion is an injury to the brain that occurs from trauma, such as a fall or a blow to the head by a hard object such as a baseball bat, hockey puck, or football helmet. The force of the blow can cause the brain to be shaken inside the skull, and may result in a loss of consciousness or symptoms such as dizziness, headache, confusion, nausea and vomiting, or blurred vision.
"The report indicates that there probably isn't anything mild about mild traumatic brain injury," Hovda tells WebMD. During development, a head injury may compromise a child's ability to excel in activities that he or she would normally excel in, he says.
"For example, if children are having problems in school or emotional problems, if they've had a previous or recent mild traumatic brain injury this particular fact should not be overlooked," he says.
The good news is that a single episode of brain injury may cause only a temporary interruption in learning or development -- as long as the child is protected from a second injury.
"Once a child has sustained an injury, that child absolutely, positively, without fail must have their brain protected from further injury," Gregory J. O'Shanick, MD, national medical director of the Brain Injury Association, tells WebMD. "These kids are at increased risk for losing more than their peers who have not had a previous injury."
Protection may mean preventing an 8-year-old child from playing football because when he was 5, he suffered an injury that caused him to black out for 10 minutes. "He does not have the room to lose anything at this point, and so we have to become even more restrictive, unfortunately. It ain't easy, but that's what one has to do to be a responsible parent," O'Shanick says.
Of even greater concern, Hovda says, are injuries that may occur during key periods of brain development, when the brain is particularly "plastic," or receptive to acquiring new information, such as learning a new language or how to play a musical instrument.
"During a child's development, there are critical windows of opportunity where the brain needs to be exposed to a particular type of stimulus in order to evolve or develop specific kinds of functions, and that length of time is different for different kinds of functions," Hovda tells WebMD.
Nearly all brain specialists and experts in child development agree that the brains of children are much more adaptable and open to experience than those of adults, under normal circumstances. But whether kids' brains remain plastic after sustaining an injury is unclear.
Furthermore, a neurosurgeon who has seen firsthand the effects of brain injuries on children says that the effects of some apparently minor brain injuries may not be seen for weeks or months after the initial accident.
"What we see is, even with mild to moderate concussions, that kids are often coming back a couple of months later, and their parents' complaint is that they're not getting the same grades in school, they just can't seem to focus, they can't concentrate. So even with minor concussions, problems in school or problems with behavior are real, cardinal signs that something more has gone on following from their injury," says David Adelson, MD, associate professor of neurosurgery at the University of Pittsburgh. He was not involved in the study.
In the report, the UCLA researchers studied rats that had sustained mild concussions and found that even when the injured young animals -- the equivalent of 5- to 7-year-old children -- are raised in a highly stimulating environment, injuries to the front part of the brain harmed their ability to learn from new experiences, compared with their normal littermates.
Also, the researchers found that the normal animals raised in the stimulating environment had significantly greater thickening of the part of the brain responsible for higher intellectual functions than did the brain-injured animals or the animals raised in standard lab-rat digs.
All three physicians interviewed by WebMD recommend that parents or caretakers of children who sustain any kind of injury that causes confusion, dizziness, or even a momentary loss of consciousness, or who vomit or feel nauseous after such an injury, should have the child seen by a doctor as soon as possible.
"There still needs to be, we believe, some time -- how much time we don't have a clear understanding, but the general consensus is that a week is a good period of time - after symptoms alleviate before the child should go back in to play," Hovda tells WebMD.