Months after sustaining a mild traumatic brain injury (mTBI) such as a concussion, the changes in a child's brain still persist even if the child is symptom-free, according to a study published online today in The Journal of Neuroscience.
Researchers from the Albuquerque-based Mind Research Network and the University of New Mexico studied 15 children between the ages of 10 and 17 who had sustained a concussion to examine the lasting effects of the injury, comparing the results to 15 healthy controls between the ages of 11 and 17.
Previous research has suggested that concussions affect the brain's white matter, which contains nerve fibers that transmit signals from one area of the brain to another, according to the National Institutes of Health.
Thus, both the healthy and concussed children underwent "diffusion tensor imaging" (DTI), which specifically images white matter in the brain, and neuropsychological testing two separate times. The concussed children were tested and imaged within 21 days of sustaining their injury, and then once more in a follow-up visit roughly three to five months after their initial screening.
In the first visit, children with the mTBIs had "cognitive dysfunction" in terms of attention and processing speed compared to their healthy peers, according to the study. The concussed children also had subtle changes in their brains' white matter.
In the follow-up visit, the researchers found that even after concussion symptoms subsided, the structural changes found in the children's white matter remained months after sustaining the original injury.
"The magnitude of the white matter changes in children with mild traumatic brain injury was larger than what has been previously been reported for adult patients with mild traumatic brain injury," said one of the study's authors, Andrew Mayer from the Mind Research Network, in a statement. "This suggests that developmental differences in the brain or the muscular-skeletal system may render pediatric patients more susceptible to injury."
Second-Impact Syndrome Implications?
Mayer and his colleagues aren't the first to posit that youths may be more susceptible to the effects of concussion due to developmental reasons. In his recent book, Concussions and Our Kids, Dr. Robert Cantu recommends restricting tackle football and soccer headers only to student-athletes who are 14 years of age or older due to developmental immaturity.
In an interview for this blog back in September, Cantu said that youths are "bobble-head dolls with big heads and weak necks," making them potentially more susceptible to injury. He noted that at the age of 14, some people are "physiologically 11 or 10," while others are "skeletally mature adults."
The finding that changes in children's white matter can persist months after a concussion, even if a child is asymptomatic, could have "important implications about when it is truly safe for a child to resume physical activities that may produce a second concussion," said Mayer in a statement.
A number of student-athletes deaths caused by head trauma over the past three decades were potentially preventable, according to a June 2011 study from the journal Pediatrics. It found 17 cases where a youth-football player died from second-impact syndrome (a brain sustaining a second concussion before fully healing from the first), which the researchers said was entirely preventable.
Mayer and his colleagues note their study's small sample size as a potential limitation, suggesting that further research is necessary to determine whether the changes detected in the three-to-five-month follow-up visit are permanent.
On a brief related note: I just went through yesterday and updated our youth-concussion law map.
Of note: Both Michigan and Hawaii have passed youth-concussion laws since July, making 43 states (including the District of Columbia) that now have such laws. Not far behind is Ohio, whose youth-concussion bill just passed through the state Senate last week after being approved by the state House in June. It's waiting to be sent to Gov. John Kasich for a signature.
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