The flow of blood to the brain of adolescent athletes is significantly reduced after concussion, a deficit which persists for more than 30 days about a third of the time, finds a recent study.1
The study, by researchers at Cincinnati Children's Hospital is significant in that it:
- adds to the growing body of evidence that the brains of children and teens are more vulnerable to concussion;
- reinforces the concept that recovery takes longer for some young athletes;
- provides support for the now commonplace prescription for cognitive rest after concussion; and
- substantiates the need for "circumspect management" of pediatric sport-related concussion.
The study involved a group of twelve children, ages 11 to 15, who had suffered sport-related concussion (SRC), two with loss of consciousness. All underwent neurocognitive, MRI, magnetic resonance spectroscopy, and angiography tests at 3 days, 14 days and 30 days or more after concussion.
The neurocognitive tests confirmed statistically significant differences in initial total symptom score and reaction time between the SRC and control groups, resolving by 14 days for total symptom score and 30 days for reaction time, but no evidence of structural injury or metabolic changes to the brain.
Significant alterations in cerebral blood flow were found among the SRC group. At 14 days, only one-quarter (27%) of the participants showed improvement in CBF; at 30 days or more after SRC CBF had still not returned to normal in more than one-third (36%) of the athletes.
"Taken together, these CBF data suggest that pediatric sport-related concussion produces a patho-physiologic process resulting in altered CBF values with a variable and possibly protracted timeframe for resolution," writes lead author, Todd A. Maugans, M.D., of the Division of Pediatric Neurosurgery at Cincinnati Children's Hospital Medical Center.
Brains more vulnerable, more conservative management needed
"Considerable clnical evidence suggests a period of vulnerability after sport-related concussion, even after symptom resolution," says Maugans. "If a concussed child returns to quickly to strenuous physical activity or experiences a second concussion, symptoms and neuropsychological testing deficits frequently worsen. ... Furthermore, catastrophic outcomes such as second impact syndrome have been attributed to probable loss of cerebral autoregulation.
Therefore, our results reinforce the concept that a protracted state of physiologic abnormality exists for some young athletes. This substantiates the need for further investigation and circumspect management of the concussed pediatric athlete," the study says.
Supports cognitive rest prescription
The study's findings have important implications for the management of pediatric concussions, says Maugans: first, because medications presently prescribed for severe post-concussive symptoms, such as stimulants, beta blockers, calcium channel blockers, and triptans, have known effects on cerebral blood flow; and second, because it proves the physiological soundness of the increasingly common prescription for cognitive rest after concussion, based on the concept of reducing cerebral metabolic demand in patients with reduced cerebral blood flow.
Maugans cautioned that, because of the small sample size and short follow-up period, the study's results were preliminary and need to be validated by larger investigations conducted over long time periods. The findings, he said, nevertheless "suggest an important role of CBF alterations in the pathophysiology of pediatric sport-related concussion."
[Editor's note: Based in part on the results of this study, MomsTEAM's expert concussion neuropsychologist, Rosemarie Scolaro Moser, recommends in her new book, Ahead of the Game: The Parents' Guide to Youth Sports Concussion, that "youth athletes not return to contact risk for at least three weeks after all symptoms have subsided."
1. Maugans T, Farley C, Altaye M, Leach J, Cecil K. Pediatric Sports-Related Concussion Produces Cerebral Blood Flow Alterations. Pediatrics 2012;129(1)(doi: 10.1542/peds.2011-2083)(accessed March 30, 2012).
Most recently revised December 27, 2012