Foreword: Sport-Related Concussion: Heads Up! xiii
Mark D. Miller
Preface: Preface xv
Peter K. Kriz
Epidemiology of Sport-Related Concussion 1
Lauren A. Pierpoint and Christy Collins
Sport-related concussions are common in the United States. Concussion rates have increased over time, likely due to improved recognition and awareness. Concussion rates vary across level (high school vs college), sex, and sport. Concussion rates are the highest among men, particularly in football, wrestling, ice hockey, and lacrosse where collisions and contact are inherent to the sports, although girls’/women’s soccer rates are high. In gender-comparable sports, women have higher concussion rates. Continued data collection will increase understanding of sport-related concussion and provide areas for targeted prevention in the future.
Biomechanics of Sport-Related Neurological Injury 19
Clara Karton and Thomas Blaine Hoshizaki
As awareness on the short-term and long-term consequences of sports-related concussions and repetitive head impacts continues to grow, so too does the necessity to establish biomechanical measures of risk that inform public policy and risk mitigation strategies. A more precise exposure metric is central to establishing relationships among the traumatic experience, risk, and ultimately clinical outcomes. Accurate exposure metrics provide a means to support evidence-informed decisions accelerating public policy mandating brain trauma management through sport modification and safer play.
The Molecular Pathophysiology of Concussion 39
David R. Howell and Julia Southard
After a concussion, a series of complex, overlapping, and disruptive events occur within the brain, leading to symptoms and behavioral dysfunction. These events include ionic shifts, damaged neuronal architecture, higher concentrations of inflammatory chemicals, increased excitatory neurotransmitter release, and cerebral blood flow disruptions, leading to a neuronal crisis. This review summarizes the translational aspects of the pathophysiologic cascade of postconcussion events, focusing on the role of excitatory neurotransmitters and ionic fluxes, and their role in neuronal disruption. We review the relationship between physiologic disruption and behavioral alterations, and proposed treatments aimed to restore the balance of disrupted processes.
Diagnosis and Sideline Management of Sport-Related Concussion 53
Andrew Gregory and Sourav Poddar
The diagnosis of sport-related concussion is still based primarily on history and physical examination. Use of a standardized history and examination form is recommended. There have been many tests investigated, but none have been proven to be sensitive and specific for the diagnosis of concussion. Sideline management is based on recognition, diagnosis, and initial treatment. It is clear that symptoms of a concussion can worsen with continued play, and so, if a concussion is suspected based on observation, history, and physical examination, then the athlete should be removed from play.
Outpatient Management of Sport-Related Concussion, Return to Learn, Return to Play 65
Peter K. Kriz and James P. MacDonald
Outpatient sports-related concussion (SRC) management continues to evolve as evidence emerges supporting a multidisciplinary approach to the clinical assessment of SRC. Early active rehabilitation has replaced strict cognitive and physical rest. With this paradigm shift in management, pragmatic approaches are highly sought by busy clinicians that provide direction to individualized treatment, which can potentially expedite symptom resolution. Treatment strategies that address domain-based symptom constellations continue to be developed by clinician researchers. Although the optimal timing and dose of these domain-specific therapies has yet to be determined, future directions of SRC treatment will answer these and other questions regarding SRC management.
Neuropsychological Assessment of Sport-Related Concussion 81
Sabrina Jennings and Michael W. Collins, and Alex M. Taylor
Neuropsychological assessment is a key component in a comprehensive, multidisciplinary approach to assessment of sport-related concussion (SRC). Currently computerized tests are the most commonly used modality of neurocognitive testing and involve both baseline and postinjury assessments. A comprehensive neuropsychological assessment should not only include neurocognitive testing but also incorporate symptom inventories, vestibular-ocular screening, and a psychological evaluation. Neuropsychological assessments are most effective when completed by a Clinical Neuropsychologist, given their specialized training in test interpretation and conceptualization of the psychological, cognitive, behavioral, physiologic, as well as neurologic principals when treating and managing SRC.
Rehabilitation of Sport-Related Concussion 93
Mohammad Nadir Haider, Lenore Herget, Ross D. Zafonte, Adam G. Lamm, Bonnie M. Wong, and John J. Leddy
This article provides a summary of clinical assessment methods and nonpharmacologic rehabilitation techniques used for concussed patients. It describes concussion-relevant physical examination methods to identify underlying symptom generators. This approach allows practitioners to prescribe targeted rehabilitation therapies to treat postconcussion symptoms. Evidence-based rehabilitation approaches include cervical rehabilitation, vestibulo-ocular rehabilitation, and sub–symptom threshold aerobic exercise.
Neuroimaging in Sports-Related Concussion 111
Gaurav Jindal, Rajan R. Gadhia, and Prachi Dubey
Mild traumatic brain injuries, or concussions, often result in transient brain abnormalities not readily detected by conventional imaging methods. Several advanced imaging studies have been evaluated in the past couple decades to improve understanding of microstructural and functional abnormalities in the brain in patients suffering concussions. The thought remains a functional or pathophysiologic change rather than a structural one. The mechanism of injury, whether direct, indirect, or rotational, may drive specific clinical and radiological presentations. This remains a dynamic and constantly evolving area of research. This article focuses on the current status of imaging and future directions in concussion-related research.
Medical Therapies for Concussion 123
Jacob C. Jones and Michael J. O’Brien
The medications used in postconcussion syndrome are typically used to help manage or minimize disruptive symptoms while recovery proceeds. These medications are not routinely used in most concussions that recover within days to weeks. However, it is beneficial to be aware of medication options that may be used in athletes with prolonged concussion symptoms or for those that have symptom burdens that preclude entry into basic concussion protocols. Medications and supplements remain a small part of the concussion treatment plan, which may include temporary academic adjustments, physical therapy, vestibular and ocular therapy, psychological support, and graded noncontact exercise.
Female Athlete and Sports-Related Concussions 133
Katherine H. Rizzone and Kathryn E. Ackerman
Female athletes are participating in collision sports in greater numbers than previously. The overall incidence of concussion is known to be higher in female athletes than in male athletes participating in similar sports. Evidence suggests anatomic, biomechanical, and biochemical etiologies behind this sex disparity. Future research on female athletes is needed for further guidance on prevention and management of concussion in girls and women.
Sports-Related Concussions and the Pediatric Patient 147
Stessie Dort Zimmerman, Brian T. Vernau, William P. Meehan III, and Christina L. Master
Pediatric patients with concussions have different needs than adults throughout the recovery process. Adolescents, in particular, may take longer to recover from concussion than adults. Initially, relative rest from academic and physical activities is recommended for 24 to 48 hours to allow symptoms to abate. After this time period, physicians should guide the return to activity and return to school process in a staged fashion using published guidelines. Further concussion research in pediatric patients, particularly those younger than high-school age, is needed to advance the management of this special population.
Prevention of Sport-Related Concussion 159
Peter K. Kriz and William O. Roberts
Concussion remains a common injury among sports participants. Implementing risk-reduction strategies for sport-related concussion (SRC) should be a priority of medical professionals involved in the care of athletes. Over the past few decades, a multifaceted approach to reducing SRC risk has been developed. Protective equipment, rule and policy change/enforcement, educational programs, behavioral modifications, legislation, physiologic modifications, and sport culture change are a few of the programs implemented to mitigate SRC risk. In this article, the authors critically review current SRC risk-reduction strategies and offer insight into future directions of injury prevention for SRC.
Long-Term Neurocognitive, Mental Health Consequences of Contact Sports 173
Barry S. Willer, Mohammad Nadir Haider, Charles Wilber, Carrie Esopenko, Michael Turner, and John Leddy
This article presents a brief history and literature review of chronic traumatic encephalopathy (CTE) in professional athletes that played contact sports. The hypothesis that CTE results from concussion or sub-concussive blows is based largely on several case series investigations with considerable bias. Evidence of CTE in its clinical presentation has not been generally noted in studies of living retired athletes. However, these studies also demonstrated limitation in research methodology. This paper aims to present a balanced perspective amidst a politically charged subject matter.
Considerations for Athlete Retirement After Sport-Related Concussion 187
Julie C. Wilson, Tatiana Patsimas, Kathleen Cohen, and Margot Putukian
The recommendation to retire from sport after concussion has evolved with the understanding of concussion. Age, sport, position, level of play, relevant medical and concussion history, severity and duration of symptoms, neuroimaging and neuropsychological testing should all be considered. Susceptibility to injury, persistence of symptoms, psychological distress, and personal values and support may also play a role. Pediatric athletes may require a more conservative approach, given ongoing growth and development. For professional and/or elite athletes, financial or career implications may be considerations. When possible, retirement should be a shared decision among the athlete, the family, and the health care team.
Future Directions in Sports-Related Concussion Management 199
Hamish Kerr, Bjørn Bakken, and Gregory House
This article focuses on 3 concepts that continue to be investigated in the search for the holy grail of concussion—a valid diagnostic test. Imaging advances are discussed with optimism that functional MRI and diffusion tensor imaging may be available clinically. Biomarkers and the use of genetic tests are covered. Sideline accelerometer use may help steer discussions of head trauma risk once technology exists to accurately estimate acceleration of the brain. In the meantime, strategies including allowing athletes to be substituted out of games for an evaluation and video review in elite sports can improve recognition of sports-related concussion.
Perspectives on the Impact of the COVID-19 Pandemic on the Sports Medicine Surgeon: Implications for Current and Future Care 213
Kyle N. Kunze, Peter D. Fabricant, Robert G. Marx, and Benedict U. Nwachukwu
As the COVID-19 (Coronavirus disease 2019) pandemic continues, the paradigm of treatment continues to rapidly evolve, especially for sports medicine surgeons, because treatment before the pandemic was considered predominantly elective. This article provides subjective and objective data on the changes implicated by the COVID-19 pandemic with regard to the interactions and practices of sports medicine surgeons. This perspective also considers the potential impact on the patients and athletes treated by sports medicine surgeons. This article discusses the impact of the COVID-19 pandemic on sports medicine and provides thoughts on how the landscape of the field may continue to change.