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).
Ice hockey
The most dangerous result of a head injury in hockey can be classified as a concussion. Most concussions occur during player-to-player contact rather than when a player is checked into the boards. Checks to the head have accounted for nearly 50% of concussions that players in the National Hockey League have suffered. Concussions that players suffer may go unreported because there is no obvious physical signs if a player is not knocked unconscious. This can prove to be dangerous if a player decides to return to play without receiving proper medical attention. Studies show that ice hockey causes 44.3% of all traumatic brain injuries among Canadian children. In severe cases, the traumatic brain injuries are capable of resulting in death. Occurrences of death from these injuries are rare.