Dr. Robert Cantu says it is not just the number of concussions an athlete suffers that are important in determining a course of treatment, but the severity, how close together they occured in time, and how severe the blow that caused the concussion. "There is no magic number" of concussions disqualifying an athlete from further play that season or is considered career-ending, Dr. Cantu explains. Individualized management is required which takes into account the totality of circumstances.
It is critically important, Dr. Cantu says, to document the number of times an athlete has experienced any post-concussion signs or symptoms not just how many concussions the athlete himself recognizes that he has sustained. This is particularly true for football players, where, Dr. Cantu says, between 60% and 80% of concussions may go unrecognized because of the episodic nature of the action and the fact that the players' helmets may mask symptoms.
While research suggests that those with prior concussions do not necessarily suffer more neurocognitive impairment following a re-injury, they have been found to be at increased risk for subsequent concussion and more likely to develop persistent post-concussion signs or symptoms, including depression, that require careful management.
Indeed, concussions suffered by athletes with a history of prior concussions, especially where concussions occur with progressively less impact force, are considered "complex" concussions warranting an interdisciplinary approach to management under the Prague concussion guidelines and, in some cases, may warrant disqualification for the rest of the season or even end an athlete's career in the sport.
The importance of finding out about concussion history is underscored by studies showing that a significant percentage of athletes, especially in contact sports like football, suffer multiple concussions over the course of their athletic career:
16.8% of high school athletes suffering a concussion had previously suffered a sport-related concussion, either that season or in a previous season;
More than 20% of concussions in boys’ and girls’ soccer and basketball were recurrent concussions.
Once an athlete has suffered an initial concussion, his or her chances of a second one are 3 to 6 times greater than an athlete who has never sustained a concussion
A third of high school players in one recent survey reported two or more concussions in a season.
High school athletes who suffer 3 or more concussions are at increased risk of experiencing loss of consciousness (8-fold greater risk), anterograde amnesia (reduced ability to form new memories after a brain injury) (5.5-fold greater risk), and confusion (5.1-fold greater risk) after a subsequent concussion.
- Children who are seen in a hospital emergency room for a head injury (concussion, skull fracture or intracranial injury) are more than twice as likely to sustain a subsequent head injury of similar type within 6 months as are children seeking care for an injury not related to the head, regardless of their age.