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.
Concussions in American football
On September 30, 2014, researchers with Boston University announced that in autopsies of 79 brains of former NFL players, 76 had tested positive for CTE. As of January 2017, that number had grown to 90 out of 94. A study published in "The Journal of the American Medical Association" in July 2017 showed that 110 of 111 former NFL players whose brains were examined were found to have suffered from CTE.