By Matthew T. McCarthy, MD, and Barry E. Kosofsky, MD, PhD
Dr. McCarthy is Resident, Department of Pediatric Neurology. New York-Presbyterian Hospital/Weill Cornell Medical College. Dr. Kosofsky is Chief, Division of Pediatric Neurology, Goldsmith Professor of Pediatrics, Neurology and Neuroscience, and Radiology, Weill Cornell Medical College
Dr. McCarthy and Dr. Kosofsky report no financial relationships relevant to this field of study.
Synopsis: The developing brain of a child may be particularly susceptible to injury from mild traumatic brain injury, such as a concussion. Recommending a longer period of strict rest after a concussion does not provide additional benefit when compared to consensus guidelines for care after a concussion in children and adolescents. However, in retired former NFL players, exposure to tackle football prior to age 12 is associated with executive dysfunction, memory impairment, and lower estimated verbal IQ later in life.
Sources: Thomas DG, et al. Benefits of strict rest after acute concussion: A randomized controlled trial. Pediatrics 2015;135:213-223. Stamm JM, et al. Age of first exposure to football and later-life cognitive impairment in former NFL players. Neurology 2015 Jan 28. pii: 10.1212/WNL.0000000000001358. [Epub ahead of print].
Filley CM, Bernick C. Children and football: A cautionary tale. Neurology 2015 Jan 28. pii: 10.1212/WNL.0000000000001357. [Epub ahead of print].
There has been increasing awareness of the incidence and potential long-term consequences of mild traumatic brain injury (mTBI) in children and young adults. While parents, school systems, and athletic programs are clamoring for evidence-based guidelines, the field remains primitive in our understanding of the factors, resulting in a spectrum of individual outcomes. Most individuals who sustain mTBI make complete recoveries, 80% within the first month, though some with ongoing symptoms exhibit sustained neurocognitive deficits. While numerous consensus “return to school and play” guidelines have been created in recent years, they are limited by the relative lack of data regarding the acute management and potential long-term outcomes after a concussion. This lack of evidence is most apparent in relation to pediatric concussion. These two studies serve to fill that knowledge gap by evaluating the potential impact of concussions on developing brains — one looking at the recommendations for management immediately post-injury and the other investigating long-term cognitive outcomes related to this type of head injury in childhood.
In the first study from Thomas et al, the authors conducted a randomized, controlled trial assessing specific recommendations for strict rest following a concussion. Eighty-eight patients aged 11-22 years presenting to a pediatric emergency department within 24 hours of a concussion were randomized to receive instructions for either the standard of care (1-2 days of rest, followed by a stepwise return to normal activity once symptoms had resolved) or 5 days of strict rest. Each participant completed a symptom rating scale, neurocognitive testing, and balance assessment at initial presentation, and then 3 and 10 days later. Activity level was self-reported by participants using diaries to account for their level of activity throughout each day.
By randomly assigning participants to either be instructed to adhere to the standard of care or strict rest for 5 days, the authors showed the following:
1) Both groups showed about 20% decrease in energy expenditure and physical activity over the first 5 days post-injury.
2) The strict rest group reported fewer hours of moderate and high mental activity in days 2-5 post-injury.
3) There were no significant differences between groups in neurocognitive testing and balance scores at day 3 and day 10.
4) Individuals in the strict rest group took longer to report symptom resolution, had overall higher symptom scores over the 10-day study period, and had higher mean symptom scores on a daily basis. This was especially apparent with physical and emotional symptoms.
5) Individuals with a past history of concussion reported more symptoms at day 10 in the strict rest group compared to the standard-of-care group, while individuals with a first-time concussion showed no difference between groups.
In the second paper by Stamm et al, the authors divided a group of former NFL players between the ages 40-69 years based on the age at which they were first exposed to tackle football (< 12 years or ≥ 12 years). The players were selected from a group comprised of individuals with recent cognitive, behavioral, or mood complaints. Each participant performed a series of standardized cognitive evaluations that measured executive function, memory, and estimated verbal IQ. After controlling for level of education, total duration of football play, and multidimensional correlation between tests and within subjects, the age of first tackle football < 12 years group performed significantly worse than the age of first tackle football ≥ 12 years group on every measurement. The total number of concussions reported was not significantly different between the two groups.
These studies focus on the acute management and potential long-term consequences of concussion in children and adolescents. Previous studies have led to disparate conclusions: Some have reported that children are able to make quicker and more complete recovery from a concussion due to greater neuronal plasticity. Others have concluded that concussion is one of the few injuries from which children recover more slowly than adults, and that they may be more susceptible to long-lasting consequences from this type of injury resulting from important developmental processes that may be disrupted by an injury during this critical period of brain maturation.
The first study begins to fill an important gap regarding specific recommendations for return to activity after a concussion in pediatric patients. It represents one of the first randomized, controlled trials evaluating such specific recommendations. Despite the numerous consensus, evidence-based guidelines that have been published recently, there have been relatively few specific recommendations for children that are based on class I evidence. For the most part, these guidelines extrapolate from adult literature and use consensus expert opinion to suggest using a more conservative approach in children given the relative lack of studies available. With this study, the authors were able to test one specific element of return to activity recommendations and demonstrated that the standard of care recommendation after an acute concussion (1-2 days of rest followed by gradual step-wise return to activity after symptoms have subsided) is preferred to an approach using a longer, strict rest period.
One possible limitation in this study is that while the strict rest group did comply with reducing mental activity compared to the standard-of-care group, they may not have adhered to strict physical rest. Additionally, there is a chance that the higher symptom scores in the strict rest group may have been the result of reporting bias. In particular, the discharge instructions may have had an influence on the perceived seriousness of the injury, leading to a change in symptom reporting, rather than actually leading to a difference in recovery between the two groups. In addition, these results may not be generalizable to all children with concussions, as this study only recruited patients who presented to the emergency department within 24 hours of an acute concussion and were discharged home. This does not take into account patients who present with persistent symptoms days after an injury or patients with more severe injuries requiring hospitalization, two groups who may benefit from an extended period of strict rest. With these caveats in mind, this report provides much needed data to help clinicians provide appropriate, evidence-based advice to their patients and families.
In the second study, the authors make an important contribution to help establish a link between concussions suffered by young children and subsequent long-term cognitive dysfunction. It has been assumed for some time that repetitive head injuries in childhood and adolescence likely impact brain development and can have long-term consequences on cognitive function. This study establishes that the risk might be even higher for permanent sequelae if the head injuries occur at a younger age during periods of critical brain development. However, it is not known what fraction of football players sustain such ongoing symptoms.
These results may not be generalizable to all populations, as the study participants were all former professional football players who are currently reporting cognitive, mood, or behavior problems. There is a much larger population of people who only play tackle football as children and adolescents who would be of interest for a similar investigation. Additionally, there may be baseline differences in verbal and cognitive abilities between children drawn to playing tackle football at an earlier age and those who do not play until they are older, as well as between individuals who do and don’t choose to play professional football. Importantly, the authors are very clear to state that although executive dysfunction and memory problems are common features of chronic traumatic encephalopathy (CTE), the results of this study do not suggest that any of the study participants have or will develop CTE. While it is conceivable that repetitive head injuries eventually lead to the pathologic changes seen in CTE, the relationship between the two is still not established and CTE remains exclusively a neuropathologic entity.
The developing brain may be uniquely susceptible to concussion, with lasting consequences on brain structure and function. However, most pediatric patients demonstrate complete recovery within days to weeks of concussion. This paradox places clinicians in a difficult situation when counseling parents and caring for children who have sustained concussions, particularly student athletes focused on rapidly returning to play. Recent guidelines published by leading thinkers and professional societies have established recommendations advising a stepwise, graded return to school and play. Those consensus statements acknowledge the need for additional research to improve the diagnosis, inform the prognosis, and facilitate the recovery of those children at risk for ongoing symptoms following concussion. These two studies are both significant in that they specifically studied pediatric populations to help develop strategies for prevention and management of concussions in this population. The results of these two studies are, in fact, coherent: Clinicians should recommend delaying the initial age of tackle football to ≥ 12 years, and following a concussion in individuals ≥ 11 years should recommend a stepwise return to normal activity once symptoms have resolved. As more data become available from studies in children, neurologists will be able to make better evidence-based recommendations for appropriate management. These studies are an essential step in that direction, and are much needed, as increasing participation in youth sports makes children the largest group of individuals at risk for concussion.