Consensus Statement on Concussion in Sport 3rd International Conference on Concussion in Sport Held in Zurich, November 2008

Abstract

Preamble This paper is a revision and update of the recommendations developed following the 1st (Vienna) and 2nd (Prague) International Symposia on Concussion in Sport.1,2 The Zurich Consensus statement is designed to build on the principles outlined in the original Vienna and Prague 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 (see Section 11). This document is developed for use by physicians, therapists, certified athletic trainers, health professionals, coaches and other people involved in the care of injured athletes, whether at the recreational, elite or professional level. While agreement exists pertaining to principal messages conveyed within this document, the authors acknowledge that the science of concussion is evolving and therefore management and return to play decisions remain in the realm of clinical judgment on an individualized basis. Readers are encouraged to copy and distribute freely the Zurich Consensus document and/or the Sport Concussion Assessment Tool (SCAT2) card, and neither is subject to any copyright restriction. The authors request, however, that the document and/or the SCAT2 card be distributed in their full and complete format. The following focus questions formed the foundation for the Zurich concussion consensus statement: Acute Simple Concussion Which symptom scale and which sideline assessment tool is best for diagnosis and/or follow up? How extensive should the cognitive assessment be in elite athletes? How extensive should clinical and neuropsychological (NP) testing be at non-elite level? Who should do/interpret the cognitive assessment? Is there a gender difference in concussion incidence and outcomes? Return to Play (RTP) Issues Is provocative exercise testing useful in guiding RTP? What is the best RTP strategy for elite athletes? What is the best RTP strategy for non-elite athletes? Is protective equipment (eg, mouthguards and helmets) useful in reducing concussion incidence and/or severity? Complex Concussion and Long-term Issues Is the Simple versus Complex classification a valid and useful differentiation? Are there specific patient populations at risk of long-term problems? Is there a role for additional tests (eg, structural and/or functional MR Imaging, balance testing, biomarkers)? Should athletes with persistent symptoms be screened for depression/anxiety? Paediatric Concussion Which symptoms scale is appropriate for this age group? Which tests are useful and how often should baseline testing be performed in this age group? What is the most appropriate RTP guideline for elite and non-elite child and adolescent athletes? Future Directions What is the best method of knowledge transfer and education? Is there evidence that new and novel injury prevention strategies work (eg, changes to rules of the game, fair play strategies, etc.)? The Zurich document additionally examines the management issues raised in the previous Prague and Vienna documents and applies the consensus questions to these areas. SPECIFIC RESEARCH QUESTIONS AND CONSENSUS DISCUSSION 1. CONCUSSION 1.1 Definition of Concussion Panel discussion regarding the definition of concussion and its separation from mild traumatic brain injury (mTBI) was held. Although there was acknowledgement that the terms refer to different injury constructs and should not be used interchangeably, it was not felt that the panel would define mTBI for the purpose of this document. There was unanimous agreement, however, that concussion is defined as follows: Concussion is defined as a complex pathophysiological process affecting the brain, induced by traumatic 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: Concussion may be caused either by a direct blow to the head, face, neck or elsewhere on the body with an ‘‘impulsive’’ force transmitted to the head. Concussion typically results in the rapid onset of short-lived impairment of neurologic function that resolves spontaneously. Concussion may result in neuropathological changes, but the acute clinical symptoms largely reflect a functional disturbance rather than a structural injury. Concussion results in a graded set of clinical symptoms that may or may not involve loss of consciousness. Resolution of the clinical and cognitive symptoms typically follows a sequential course; however, it is important to note that, in a small percentage of cases, post-concussive symptoms may be prolonged. No abnormality on standard structural neuroimaging studies is seen in concussion. 1.2 Classification of Concussion There was unanimous agreement to abandon the Simple vs. Complex terminology that had been proposed in the Prague agreement statement, as th