This white paper is an international collaborative effort to address concussion management, science, policy and future directions. This article is driven by data and rooted in science. There has been no sponsorship or financial interest influencing the development of this statement of agreement. This consensus statement will be constantly updated based on advances in science. These efforts aim to provide much needed direction for concussion management rendered by school boards, workers’ compensation boards, amateur and professional sporting associations, as well as insurance providers and government. The aforementioned groups are encouraged to strive towards the best medical practices outlined in this white paper. Concussed individuals may reference this policy paper when advocating for care.
Persistent Differences in Patterns of Brain Activation after Sports-Related Concussion: A Longitudinal Functional Magnetic Resonance Imaging Study
Abstract
Avoiding recurrent injury in sports-related concussion (SRC) requires understanding the neural mechanisms involved during the time of recovery after injury. The decision for return-to-play is one of the most difficult responsibilities facing the physician, and so far this decision has been based primarily on neurological examination, symptom checklists, and neuropsychological (NP) testing. Functional magnetic resonance imaging (fMRI) may be an additional, more objective tool to assess the severity and recovery of function after concussion. The purpose of this study was to define neural correlates of SRC during the 2 months after injury in varsity contact sport athletes who suffered a SRC. All athletes were scanned as they performed an n-back task, for n = 1, 2, 3. Subjects were scanned within 72 hours (session one), at 2 weeks (session two), and 2 months (session three) post-injury. Compared with age and sex matched normal controls, concussed subjects demonstrated persistent, significantly increased activation for the 2 minus 1 n-back contrast in bilateral dorsolateral prefrontal cortex (DLPFC) in all three sessions and in the inferior parietal lobe in session one and two (a £ 0.01 corrected). Measures of task performance revealed no significant differences between concussed versus control groups at any of the three time points with respect to any of the three n-back tasks. These findings suggest that functional brain activation differences persist at 2 months after injury in concussed athletes, despite the fact that their performance on a standard working memory task is comparable to normal controls and normalization of clinical and NP test results. These results might indicate a delay between neural and behaviorally assessed recovery after SRC.
Key words: concussion; DLPFC; fMRI; n-back task; working memory
In the past decade, few issues at the intersection of medicine and sports have had
as high a profile or have generated as much public interest as sports-related concussions.
In recent years there has been a growing awareness and understanding that all
concussions involve some level of injury to the brain and that athletes suspected of
having a concussion should be removed from play for further evaluation (CDC, 2013;
Halstead et al., 2010). Despite the increased attention, however, confusion and
controversy persist in many areas, from how to define a concussion and how multiple
concussions affect the vulnerability of athletes to future injury, to when it is safe for a
player to return to sports and the effectiveness of protective devices and other
interventions in reducing the incidence and severity of concussive injuries (Wilde et al.,
2012). Parents worry about choosing sports that are safe for their children to play, about
finding the equipment that can best protect their children, and about when, if a child does
receive a concussion, it will be safe for him or her to return to play or if it might be time
to quit a much-loved sport entirely.
It is within this context that the Institute of Medicine (IOM) and National
Research Council (NRC), in October 2012, convened the Committee on Sports-Related
Concussions in Youth to review the science of sports-related concussions in youth from
elementary school through young adulthood, including military personnel and their
dependents, and to prepare a report on that topic based on that review. The committee
was charged with reviewing the available literature on concussions within the context of
developmental neurobiology, specifically relating to the causes of concussions, their
relationship to impacts to the head or body during sports, the effectiveness of protective
devices and equipment, screening for and diagnosis of concussions, their treatment and
management, and their long-term consequences. Specific topics of interest included
the acute, subacute, and chronic effects of single and repetitive concussive and
non-concussive head impacts on the brain;
risk factors for sports concussions, post-concussion syndrome, and chronic
traumatic encephalopathy;
the spectrum of cognitive, affective, and behavioral alterations that can occur
during acute, subacute, and chronic posttraumatic phases;
physical and biological triggers and thresholds for injury;
the effectiveness of equipment and sports regulations in preventing injury;
hospital- and non-hospital-based diagnostic tools; and
Kevin Flynn covers the futures of FIFA and Sepp Blatter with Jeremy Schaap, MLS’ perception with Ben Grossman and the management of head injuries with David Goldstein.
