American Medical Society for Sports Medicine position statement: concussion in sport.

PURPOSE OF THE STATEMENT: To provide an evidence-based, best practises summary to assist physicians with the evaluation and management of sports concussion. To establish the level of evidence, knowledge gaps and areas requiring additional research. 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. 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. Experimental evidence suggests the concussed brain is less responsive to usual neural activation and when premature cognitive or physical activity occurs before complete recovery the brain may be vulnerable to prolonged dysfunction. INCIDENCE: It is estimated that as many as 3.8 million concussions occur in the USA per year during attention-deficit disorders (ADD/ADHD) and migraine headaches complicate checklists provide an objective tool for assessing a variety of symptoms related to concussions, while also tracking the severity of those symptoms over serial evaluations. Standardised assessment tools provide a helpful structure for the evaluation of concussion, although limited validation of these assessment tools is available. SIDELINE Additional research is needed to validate current assessment tools, delineate the role of NP testing and improve identification of those at risk of prolonged post-concussive symptoms or other long-term complications. Evolving technologies for the diagnosis of concussion, such as newer neuroimaging techniques or biological markers, may provide new insights into the evaluation and management of sports concussion.