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April 16, 1997

Sports-Related Recurrent Brain Injuries— United States

JAMA. 1997;277(15):1190-1191. doi:10.1001/jama.1997.03540390020009

AN ESTIMATED 300000 sports-related traumatic brain injuries (TBIs) of mild to moderate severity,1 most of which can be classified as concussions (i.e., conditions of temporarily altered mental status as a result of head trauma), occur in the United States each year. The proportion of these concussions that are repeat injuries is unknown; however, there is an increased risk for subsequent TBI among persons who have had at least one previous TBI.2,3 Repeated mild brain injuries occurring over an extended period (i.e., months or years) can result in cumulative neurologic and cognitive deficits,4,5 but repeated mild brain injuries occurring within a short period (i.e., hours, days, or weeks) can be catastrophic or fatal. The latter phenomenon, termed "second impact syndrome," has been reported more frequently since it was first characterized in 1984.6-8This report describes two cases of second impact syndrome and presents recommendations developed