Summary: American Medical Society for Sports Medicine Position Statement: Concussion in Sport. (Abridged Version - DM)
DEFINITION: Concussion is defined as a traumatically induced transient disturbance of brain function and involves a complex pathophysiological process. Concussion is a subset of mild traumatic brain injury (MTBI) which is generally self-limited and at the less-severe end of the brain injury spectrum.
PATHOPHYSIOLOGY: Animal and human studies support the concept of postconcussive vulnerability, showing that a second blow before the brain has recovered results in worsening metabolic changes within the cell.
INCIDENCE: It is estimated that as many as 3.8 million concussions occur in the USA per year during competitive sports and recreation activities; however, as many as 50% of the concussions may go unreported.
RISK FACTORS FOR SPORT-RELATED CONCUSSION: A history of concussion is associated with a higher risk of sustaining another concussion. A greater number, severity and duration of symptons after a concussion are predictors of a prolonged recovery. In sports with similar playing rules, the reported incidence of concussion is higher in female athletes than in male athletes. Certain sports, positions and individual playing styles have a greater risk of concussion.
DIAGNOSIS OF CONCUSSION: Concussion remains a clinical diagnosis ideally made by a healthcare provider familiar with the athlete and knowledgeable in the reognition and evaluation of concussion. Graded sympton chceklists provide an objective tool for assessing a variety of symptons related to concussions, while also tracking the severity of those symptons over serial evaluations. Standardized assessment tools provide a helpful structure for the evaluation of concussion, although limited validation of these assessment tools is available.
SIDELINE EVALUATION AND MANAGEMENT: Any athlete suspected of having a concussion should be stopped from playing and assessed by a licensed healthcare provider trained in the evaluation and management of concussions. Recognition and initial assessment of a concussion should be guided by a symptoms checklist, cognitive evaluation (including orientation, past and immediate memory, new learing and concentration), balance tests and further neurological physical examination. While standardized sideline tests are a useful framework for examination,... Their practical usefulness with or without an individual baseline test is also largely unknown.
NEUROPSYCHOLOGICAL TESTING: Neuropsychological (NP) test are an objective measure of brain-behavior relationships and are more sensitive for subtle cognitive impairment than clinical exam. Most concussions can be managed appropriately without the use of NP testing. Computerized neuropsychological (CNP) testing should be interpreted by healthcare professionals trained an familiar with the type of test and the individual test limitations, including a knowledgeable assessment of the reliable change index, baseline variability and false-positive and false-negative rates. The ideal timing, frequency and type of NP testing have not been determined. It is unknown if use of NP testing in the management of sports concussion helps prevent recurrent concussion, catastrophic injury or long-term complications.
RETURN TO PLAY: Concussion symptoms should be resolved before returning to exercise. A RTP progression involves a gradual, step-wise increase in physical demands, sports-specific activities and the risk for contact. If symptons occur with activity, the progression should be halted and restarted at the preceding sympton-free step.
LONG-TERM EFFECTS: There is an increasing concern that head impact exposure and recurrent concussions contribute to long-term neurological sequelae. Some studies have suggested an association between prior concussions and chronic cognitive dysfunction. Large-scale epideiological studies are needed to more clearly define risk factors and causation of any long-term neurological impairment.