@article{ref1,
title="What definition is used to describe second impact syndrome in sports? A systematic and critical review",
journal="Current sports medicine reports",
year="2017",
author="Stovitz, Steven D. and Weseman, Jonathan D. and Hooks, Matthew C. and Schmidt, Robert J. and Koffel, Jonathan B. and Patricios, Jon S.",
volume="16",
number="1",
pages="50-55",
abstract="Concern about what has been termed, &quot;second impact syndrome&quot; (SIS) is a major factor determining return-to-play decisions after concussion. However, definitions of SIS vary. We used Scopus to conduct a systematic review and categorize the definitions used to describe SIS. Of the 91 sources identified, 79 (87%) clearly specified that SIS involved either cerebral edema or death after a concussion when a prior concussion had not resolved. Twelve articles (13%) could be interpreted as merely the events of two consecutive concussions. Among the articles that listed mortality rates, nearly all (33/35, 94%) said the rate of death was &quot;high&quot; (e.g., 50% to 100%). Our review found that most articles define SIS as a syndrome requiring catastrophic brain injury after consecutive concussive episodes. Given that it is unclear how common it is to have a second concussion while not fully recovered from a first concussion, the actual mortality rate of SIS is unknown.<p /> <p>Language: en</p>",
language="en",
issn="1537-890X",
doi="10.1249/JSR.0000000000000326",
url="http://dx.doi.org/10.1249/JSR.0000000000000326"
}