Post-concussion syndrome
Post-concussion syndrome, also known as postconcussive syndrome or PCS, is a set of symptoms that may continue for weeks, months, or a year or more after a concussion – a mild form of traumatic brain injury (TBI). The rates of PCS vary, but most studies report that about 15% of individuals with a history of a single concussion develop persistent symptoms associated with the injury. A diagnosis may be made when symptoms resulting from concussion last for more than three months after the injury. Loss of consciousness is not required for a diagnosis of concussion or post-concussion syndrome.
Second-impact syndrome
Second-impact syndrome shares all the risk factors of concussion; that is, those who are at increased risk for concussion are also at higher risk for SIS. Thus, people who participate in sports such as boxing, soccer, American football, baseball, rugby, basketball, ice hockey, pro wrestling, and skiing (especially Alpine) are at increased risk. The condition most commonly occurs in American football.