Post-concussion syndrome
Though no universally accepted definition of postconcussive syndrome exists, most of the literature defines the syndrome as the development of at least 3 of the following symptoms: headache, dizziness, fatigue, irritability, impaired memory and concentration, insomnia, and lowered tolerance for noise and light. One complication in diagnosis is that symptoms of PCS also occur in people who have no history of head injury, but who have other medical and psychological complaints. In one study 64% of people with TBI, 11% of those with brain injuries, and 7% of those with other injuries met the DSM-IV criteria for post-concussion syndrome. Many of these PCS sufferers were misdiagnosed as having other unrelated conditions due to commonality of symptoms. (see diagnosis, below).
Second-impact syndrome
In 2002, a high-school football player from Texas named Will Benson suffered two concussions within two weeks; he collapsed shortly after the second one and died six days later as the result. He is thought to have died from SIS. Will's Bill, a law for which the father of the player had advocated after his son's death, was passed in Texas in June 2007. The law mandates basic emergency and safety training for sports officials in high schools, including education about second-impact syndrome, with a special focus on concussion symptoms.