A single sports-related concussion in an adolescent leads to a significant reduction in cerebral blood flow (CBF) that may persist for more than 1 month after the injury, new research suggests.
“This study adds to the expanding evidence that concussion is a serious injury that takes considerable time to recover from for many kids,” Todd A. Maugans, MD, from the Division of Pediatric Neurosurgery, Cincinnati Children’s Hospital Medical Center in Ohio, told Medscape Medical News.
Among 12 concussed 11- to 15-year-olds in this study, two thirds still had CBF alterations at 2 weeks, and one quarter at 1 month. Furthermore, Dr. Maugans said, “clinical recovery by testing and symptom resolution did not predict physiologic recovery in this small group of concussed kids.”
However, the researchers did not find measurable evidence of structural damage. “At least in younger children, sports concussion does not seem to cause serious structural or metabolic injuries, which is different than adults,” Dr. Maugans said, “so parents do not need to worry that a single sports concussion has likely done any serious permanent damage.”
The study was published online November 30 in Pediatrics and will appear in the January 2012 print issue of the journal.
Support for Slow Return-to-Play Policy
Reached for comment, Michael F. Bergeron, PhD, FACSM, who was not involved in the study, said the study is “noteworthy” in that it supports previous studies in adults indicating that head trauma can lead to altered CBF.
This study now “extends those findings to a pediatric population,” said Dr. Bergeron, executive director of the National Institute for Athletic Health and Performance and the National Youth Sports Health and Safety Institute at Sanford University of South Dakota Medical Center in Sioux Falls.
He said these “lingering ‘non-visible’ effects reinforce why return to play (and school) needs to be carefully and individually assessed, even without reported symptoms or obvious clinical signs.”
Dr. Maugans also cautioned: “We do not believe the study is large and definitive enough to cause a change in management of sports-related concussion; however, a slow and systematic return to play, as is being espoused by most sports medicine experts, is very much justified by our work.”
Dr. Maugans and colleagues assessed 12 adolescents who suffered a concussion during soccer (3 children), football (8 children), or wrestling (1 child). The children underwent a battery of tests at less than 72 hours, 14 days, and 30 days or more after the concussion.
Tests included the Immediate Postconcussion Assessment and Cognitive Testing (ImPACT) neurocognitive exam, T1 and susceptibility weighted magnetic resonance imaging, diffusion tensor imaging, proton magnetic resonance spectroscopy, and phase contrast angiography. The researchers also evaluated 12 age- and sex-matched control patients at a single time.
The ImPACT test results confirmed statistically significant differences between concussed youth and control youth in initial total symptom score (mean, 27.8 vs 4.08; P = .0025), with symptoms easing by 14 days (mean, 11.17 vs 4.08; P = .1108) and resolving by 30 days (mean, 3.78 vs 4.08; P = .8701).
Initial postinjury reaction times were also significantly longer in the concussed group (mean, 0.73 vs 0.59 seconds), which persisted at 14 days after injury (mean, 0.68 vs 0.59 seconds) and reached control levels at 30 days (mean, 0.66 vs 0.59 seconds).
CBF Alterations, but No Evidence of Structural Damage
Statistically significant alterations in CBF were seen in the concussed group, with reduction in CBF predominating (38 vs 48 mL/100 g/minute; P = .027). Improvement toward control values occurred in only 27% of the concussed youth at 14 days postinjury, and 64% at more than 30 days postinjury.
“The actual time frame of CBF normalization needs to be better defined in a larger study,” Dr. Maugans told Medscape Medical News. “During the recovery time, rest, hydration, [and] avoidance of another concussion are all prudent.” It is possible that increasing nutritional substances known to increase CBF, such as flavonoids (cocoa) and nitrites (green leafy vegetables) may be helpful, he added, “although this clearly needs to be studied.”
However, although there was no evidence of gross structural injury on any of the tests employed, Dr. Bergeron cautions that “this does not with certainty indicate there is no structural damage. It underscores the complexity of concussion and the challenge of finding sufficient and appropriate objective measures to profile the injury status and guide the clinical evaluation and return-to-play process. CBF may indeed be one of those more ‘objective’ measures,” he said.
The study was supported by the National Institutes of Health. The authors and Dr. Bergeron have disclosed no relevant financial relationships.
Pediatrics. Published online November 30, 2011
