Consensus Statement on Concussion in Sport: The 4th International Conference on Concussion in Sport, Zurich, November 2012

This paper is a revision and update of the recommendations developed following the 1st (Vienna 2001), 2nd (Prague 2004), and 3rd (Zurich 2008) International Consensus Conference on Concussion in Sport and is based on the deliberations at the 4th International Conference on Concussion in Sport held in Zurich, November 2012.1–3The new 2012 Zurich Consensus statement is designed to build on the principles outlined in the previous documents and to develop further conceptual understanding of this problem using a formal consensus-based approach. A detailed description of the consensus process is outlined at the end of this document under the “Background” section. This document is developed for use by physicians and health care professionals who are primarily involved in the care of injured athletes, whether at the recreational, elite, or professional level.While agreement exists pertaining to principle messages conveyed within this document, the authors acknowledge that the science of concussion is evolving, and therefore, management and RTP decisions remain in the realm of clinical judgment on an individualized basis. Readers are encouraged to copy and distribute freely the Zurich Consensus document, the Pocket Concussion Recognition Tool (CRT), the Sports Concussion Assessment Tool version 3 (SCAT3), and the Child SCAT3 card (Appendix), and none is subject to any restriction, provided it is not altered in any way or converted to a digital format. The authors request that the document and the accompanying tools be distributed in their full and complete format.This consensus paper is broken into a number of sections:The Zurich 2012 document examines sport concussion and management issues raised in the previous Vienna 2001, Prague 2004, and Zurich 2008 documents and applies the consensus questions from Section 3 to these areas.1–3Panel discussion regarding the definition of concussion and its separation from mild traumatic brain injury (mTBI) was held. There was acknowledgement by the Concussion in Sport Group (CISG) that, although the terms mild traumatic brain injury (mTBI) and concussion are often used interchangeably in the sporting context and particularly in the US literature, others use the term to refer to different injury constructs. Concussion is the historical term representing low-velocity injuries that cause brain “shaking,” resulting in clinical symptoms, and which are not necessarily related to a pathologic injury. Concussion is a subset of TBI, and the term concussion will be used in this document. It was also noted that the term commotio cerebri is often used in European and other countries. Minor revisions were made to the definition of concussion and it is defined as follows: Concussion is a brain injury and is defined as a complex pathophysiological process affecting the brain, induced by biomechanical forces. Several common features that incorporate clinical, pathologic, and biomechanical injury constructs that may be utilized in defining the nature of a concussive head injury include:The majority (80% to 90%) of concussions resolve in a short (7–10 day) period, although the recovery timeframe may be longer in children and adolescents.2The diagnosis of acute concussion usually involves the assessment of a range of domains including clinical symptoms, physical signs, cognitive impairment, neurobehavioral features, and sleep disturbance. Furthermore, a detailed concussion history is an important part of the evaluation, both in the injured athlete and when conducting a preparticipation examination. The detailed clinical assessment of concussion is outlined in the SCAT3 and Child SCAT3 forms, which are appendices to this document.The suspected diagnosis of concussion can include 1 or more of the following clinical domains:If any 1 or more of these components is present, a concussion should be suspected and the appropriate management strategy instituted.When a player shows any features of a concussion:Sufficient time for assessment and adequate facilities should be provided for the appropriate medical assessment, both on and off the field, for all injured athletes. In some sports, this may require rule change to allow an appropriate off-field medical assessment to occur without affecting the flow of the game or unduly penalizing the injured player's team. The final determination regarding concussion diagnosis and fitness to play is a medical decision based on clinical judgment.Sideline evaluation of cognitive function is an essential component in the assessment of this injury. Brief neuropsychological test batteries that assess attention and memory function have been shown to be practical and effective. Such tests include the SCAT3, which incorporates the Maddocks questions,4,5 and the Standardized Assessment of Concussion (SAC).6–8 It is worth noting that standard orientation questions (eg, time, place, person) have been shown to be unreliable in the sporting situation when compared with memory assessment.5,9 It is recognized, however, that abbreviated testing paradigms are designed for rapid concussion screening on the sidelines and are not meant to replace comprehensive neuropsychological testing, which should ideally be performed by trained neuropsychologists who are sensitive to subtle deficits that may exist beyond the acute episode; nor should they be used as a standalone tool for the ongoing management of sports concussions.It should also be recognized that the appearance of symptoms or cognitive deficit might be delayed several hours after a concussive episode and that concussion should be seen as an evolving injury in the acute stage.An athlete with concussion may be evaluated in the emergency room or doctor's office as a point of first contact after injury or may have been referred from another care provider. In addition to the points outlined above, the key features of this exam should encompass:In large part, the points above are included in the SCAT3 assessment.A range of additional investigations may be used to assist in the diagnosis or exclusion of injury. Conventional structural neuroimaging is typically normal in concussive injury. Given that caveat, the following suggestions are made. Brain computed tomography (CT; or where available, magnetic resonance imaging [MRI]) contributes little to concussion evaluation but should be employed whenever suspicion of an intracerebral or structural lesion (eg, skull fracture) exists. Examples of such situations may include prolonged disturbance of conscious state, focal neurological deficit, or worsening symptoms.Other imaging modalities, such as functional MRI (fMRI) demonstrate activation patterns that correlate with symptom severity and recovery in concussion.10–14 While not part of routine assessment at the present time, they nevertheless provide additional insight to pathophysiologic mechanisms. Alternative imaging technologies (eg, positron emission tomography, diffusion tensor imaging, magnetic resonance spectroscopy, functional connectivity), while demonstrating some compelling findings, are still at early stages of development and cannot be recommended other than in a research setting.Published studies, using both sophisticated force-plate technology, as well as those using less sophisticated clinical balance tests (eg, Balance Error Scoring System), have identified acute postural stability deficits lasting approximately 72 hours after sport-related concussion. It appears that postural-stability testing provides a useful tool for objectively assessing the motor domain of neurologic functioning and should be considered a reliable and valid addition to the assessment of athletes suffering from concussion, particularly where symptoms or signs indicate a balance component.15–21The significance of apolipoprotein (Apo) E4, ApoE promotor gene, tau polymerase, and other genetic markers in the management of sports concussion risk or injury outcome is unclear at this time.22,23 Evidence from human and animal studies in more severe traumatic brain injury demonstrates induction of a variety of genetic and cytokine factors, such as insulin-like growth factor-1 growth growth and such are in sporting concussion is not at this In and of brain injury have been as by which may be There is however, to the routine use of these (eg, magnetic and have in the however, not all studies athletes from The clinical significance of these to be of neuropsychological testing in concussion been shown to be of clinical and contributes in concussion in cognitive recovery with the time of symptom it been that cognitive recovery may or more clinical symptom that the assessment of cognitive function should be an important component in the assessment of concussion in any RTP It be however, that assessment should not be the of management it should be seen as an to the clinical process in with a range of of different clinical domains and is recommended that all athletes should have a clinical neurological assessment assessment of their cognitive as part of their This will be by the often in with screening testing is not for all however, when this is considered it should ideally be performed by a trained neuropsychologists are in the to tests by of their and the RTP decision should remain a medical in which a when been In the of and other (eg, formal balance testing, a more RTP may be testing may be used to assist RTP decisions and is typically performed when an athlete is assessment may important in the early stages after There may be situations where testing is performed early to assist in of management (eg, to in a This will be in with a trained testing was considered by the and was not to be as a of it may be or useful to the of these It also provides an additional for the to the significance of this injury with the present, is to the routine use of of concussion management is physical and cognitive the acute symptoms resolve and a of medical and The the of after a sport-related concussion is of in the acute after injury may be of research to the outcome of and the and of is In the of a involves the to and contact in a that not in a of for those who are to may be of although the after injury for of this is above, the majority of injuries will several In these it is that an athlete will a RTP RTP after a concussion a process as outlined in this the athlete should to to the at the should that an athlete approximately 1 to the full at and with any symptoms occur while in the the should to the previous and to after a further of was that RTP on the of concussive injury should There are demonstrating that, at the and athletes to RTP on the may demonstrate deficits that may not be on the sidelines and are more to have delayed of symptoms are in of In symptoms are not to concussion, and it is important to other of concussion in sport where clinical recovery the should be in a by health care with in may have in this particularly with the are also encouraged to the athlete for symptoms such as and as these symptoms are common in all of traumatic brain in sports concussion may be in The first of these situations is the management of or prolonged symptoms (eg, sleep The situation is where is used to the of the with the of the of the concussion In this to management should be considered by in concussion important in RTP is that athletes should not be symptom but also should not be any or that may or the symptoms of concussion. may be the management of a concussion, the decision to RTP while still on such be considered by the the of a concussion history and the that athletes will not all the concussions they may have in the a detailed concussion history is of Such a history may athletes who into a risk and provides an for the health care to the athlete in to the significance of concussive injury. A concussion history should include questions as to previous symptoms of a concussion and of not the number of It is also worth noting that the of concussive injuries by or been to be The clinical history should also include all previous and as these may also have clinical It is worth that in the of and concussive injuries may be pertaining to may the to a to injury. part of the clinical it is that regarding employed at time of injury be both for and is an additional and often of the preparticipation physical as the evaluation for an with the player as well as of of range of may the and management of concussion in some may the for prolonged or in some the for their is be important to in a detailed concussion history and are outlined in of as a in the management of concussion was at by the There was not agreement that the research is for this to be included as a although it was that may be a risk for injury or injury severity the management of to severe traumatic brain of of is an of While in concussion with early cognitive it not been noted as a of injury Consensus discussion that prolonged be considered as a that may is in the of and its as a of injury that the and of the clinical symptoms may be more important than the or of it be noted that with the time of and is of injury variety of motor (eg, or may a concussion. these clinical features are and require management beyond the standard of the concussive health issues as have been as a of all of traumatic brain including concussion. studies using that a after concussion may an pathophysiological with a of While such health issues may be in it is recommended that the these issues in the management of evaluation and management recommendations can be to children and to the of that children concussion symptoms different from and require symptom as a component of additional in assessing the or athlete with a concussion is that the clinical evaluation by the health care professional may to include both and and and when A SCAT3 been developed to assess concussion for those decision to use testing is the as the assessment although are some of testing may in to assist in and cognitive testing is it be sensitive to the ongoing cognitive that this in the of to the or to In this it is more important to the use of trained neuropsychologists to assessment particularly in children with or who may more sophisticated assessment was by the that to sport or should occur the or athlete to to In the of was with to a to with of that may and may also to be to of should not be to sport symptom which may require a longer timeframe than for of the different and longer recovery after concussion and (eg, related to head and a more RTP is It is appropriate to the of time of or the of the in children and It is not appropriate for a or athlete with concussion to RTP on the as the of the of Concussion more to this than and may more RTP athletes, of of should be using the and RTP The and in concussion evaluation are of more in management than a separation and athlete formal testing may be beyond the of sports or it is recommended that, in all sports, be to this cognitive evaluation, of the or of to be of the for in the management of all athletes. it was that traumatic a with an in It was further that a not been and concussions or to contact present, the of in the studies should It was also recognized that it is important to the of and athletes from related to the of is clinical that will concussion, although have a in and injury. studies have shown a in to the brain with the use of head and but these have not been to a in concussion and are a number of studies to that provide head and injury and should be recommended for in In sports, such as and motor and sports, may other of head injury (eg, skull fracture) that are related to on and may be an important for those of rule to the head injury or severity may be appropriate where a is in a of this is in where research studies that contact in for approximately of noted rule also may be in some sports to allow an off-field medical assessment to occur without the affecting the flow of the or unduly penalizing the player's team. It is important to that rule may be a of injury risk in these and play an important in this important in the use of is the of risk This is where the use of in change such as the of more which can in a in injury The to which this is in more in the in the of Sports This may be a in and athletes, in head injury are often than in nature of sport that it to play and should not be sporting should be encouraged to that may concussion play and should be as key of the to or the of concussive injury after the is of athletes, and the is a of in this and health care be regarding the of concussion, its clinical features, assessment and principles of to including and are important in the In concussion the and of sport such as the International International and International that this have and be play and for are that should be encouraged in all sports and sporting and play an important part in these are on the of November 2001, the 1st International Conference on Concussion in Sport was held in This was by the in with and the of the part of the resulting for the the for and were The 2nd International Conference on Concussion in Sport was by the with the additional of the and was held in in November The of the were to provide recommendations for the of and health of athletes who concussive injuries in and as well as other this a range of were to both to issues of and clinical injury cognitive assessment, new research and 3rd International Conference on Concussion in Sport was held in Zurich, on 2008 and was designed as a formal consensus following the by the US of of the consensus can be at The principles the of a consensus development are not with any The was for the consensus and the were from clinical and research in the of concussion. not but were for their and understanding of this 4th International Conference on Concussion in Sport was held in Zurich, on November 2012 and the as for the 3rd consensus and authors were to an International of for of of related to and of will be made on the Concussion in Sport Group and with the of Sports consensus document the of and will to be to the development of new It provides an of issues that may be of to health care involved in the management of concussion. It is not as a standard of care and should not be as This document is a and is of a with the of a health care will on the and to is that this document will be and to 1 that is the subject of a that is in the of Sports all and of will be in those consensus that concussion is an evolving injury in the acute with clinical signs and symptoms, which may the injury in the Concussion is considered to be the complex injuries in sports to and The majority of concussions in sport occur without or neurologic present, is test or that can on for an diagnosis of concussion in the sporting of this evolving it is not to rule concussion when an injury with a neurologic such should be from the and for concussion by the or health care as It was recognized that a cognitive deficit is not for acute as it may not be present or not on is a clinical diagnosis based on the injury signs, and The majority of concussions referred to as occur without or neurologic In of concussion, the athlete might be without In concussions cannot be identified or by neuroimaging (eg, or Several tests are appropriate for use in the assessment of acute concussion in the sporting tests provide important on symptoms and functional that can incorporate into their but should not be used to and concussion in the athlete on the is a for the health care provider. this is often a rapid assessment in the of with a time and the athlete to A assessment of which more is in decisions for the The evaluation of concussion is often a the and of in a and of assessment and on these the evaluation is based on of assessment of symptoms, cognitive and and are often Concussion is often an evolving and signs and symptoms may be on the of an athlete of when is any suspicion for is A assessment of concussion is useful in the assessment of the athlete with suspected concussion but should not the of was that a variety of should be employed as part of the assessment of concussion to provide a more complete clinical for the clinical can be in a the use of a such as the A assessment is it is that further studies to be performed to this test should include an assessment of injury severity using the by and concussion this is symptom and symptom and balance function should be in any athlete suspected of a concussion. It is recommended that these be after a on the to the of or on the While it is noted that this timeframe is an nevertheless the that a of was important research should the for of tests such as the test and clinical time studies that these may be useful to the assessment of concussion. the for additional may for was further that the SCAT3 be for and and while a new tool be developed for concussions are with 1 or more symptoms, or cognitive deficits a of can be using symptom balance testing, and 3 can in the first after with The of symptoms and the of recovery can be which the of assessing all 3 as part of a comprehensive sports concussion assessment been by the Concussion in Sport Group as a of concussion are to tests and can play an important within the context of a and to concussion. Concussion management that use assessment to assist in clinical decision have been in professional sports, and Brief cognitive evaluation tools are the of these the in trained however, it should be noted that these are not for formal present, is to the routine use of number of exist to assess concussion but not motor assessment, technology, functional imaging and and head this exists for their in this and none have been as It will be important to the of these technologies is the of and after a concussion is of may be of further research to the outcome of and the and of is for those who are to may be of although the after injury for of this is for with clinical of or may be of There is a for studies the of a period, and for who have a symptoms are in of This may be in sports (eg, and (eg, In symptoms are not to concussion, and it is important to and may include formal testing and neuroimaging to structural injury. is to routine clinical use of neuroimaging or other of concussion in sport in which clinical recovery the should be in a by health care with in concussion. components of management after the of physical and cognitive include such as and of assessment of other of prolonged and of of a at a that not demonstrates that the number and severity of symptoms and previous concussions are with prolonged recovery or risk of Brief of or not outcome after concussion, although a should be in an athlete with prolonged longer to from and assessment batteries have to be in the are on the of and on outcome after concussion. 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